Expand PMF_FN_* macros.

[netbsd-mini2440.git] / dist / ntp / util / ntp-keygen.c

/*      $NetBSD: ntp-keygen.c,v 1.11 2007/08/18 05:48:46 kardel Exp $   */

/*
 * Program to generate cryptographic keys for NTP clients and servers
 *
 * This program generates files "ntpkey_<type>_<hostname>.<filestamp>",
 * where <type> is the file type, <hostname> is the generating host and
 * <filestamp> is the NTP seconds in decimal format. The NTP programs
 * expect generic names such as "ntpkey_<type>_whimsy.udel.edu" with the
 * association maintained by soft links.
 *
 * Files are prefixed with a header giving the name and date of creation
 * followed by a type-specific descriptive label and PEM-encoded data
 * string compatible with programs of the OpenSSL library.
 *
 * Note that private keys can be password encrypted as per OpenSSL
 * conventions.
 *
 * The file types include
 *
 * ntpkey_MD5key_<hostname>.<filestamp>
 *      MD5 (128-bit) keys used to compute message digests in symmetric
 *      key cryptography
 *
 * ntpkey_RSAkey_<hostname>.<filestamp>
 * ntpkey_host_<hostname> (RSA) link
 *      RSA private/public host key pair used for public key signatures
 *      and data encryption
 *
 * ntpkey_DSAkey_<hostname>.<filestamp>
 * ntpkey_sign_<hostname> (RSA or DSA) link
 *      DSA private/public sign key pair used for public key signatures,
 *      but not data encryption
 *
 * ntpkey_IFFpar_<hostname>.<filestamp>
 * ntpkey_iff_<hostname> (IFF server/client) link
 * ntpkey_iffkey_<hostname> (IFF client) link
 *      Schnorr (IFF) server/client identity parameters
 *
 * ntpkey_IFFkey_<hostname>.<filestamp>
 *      Schnorr (IFF) client identity parameters
 *
 * ntpkey_GQpar_<hostname>.<filestamp>,
 * ntpkey_gq_<hostname> (GQ) link
 *      Guillou-Quisquater (GQ) identity parameters
 *
 * ntpkey_MVpar_<hostname>.<filestamp>,
 *      Mu-Varadharajan (MV) server identity parameters 
 *
 * ntpkey_MVkeyX_<hostname>.<filestamp>,
 * ntpkey_mv_<hostname> (MV server) link
 * ntpkey_mvkey_<hostname> (MV client) link
 *      Mu-Varadharajan (MV) client identity parameters
 *
 * ntpkey_XXXcert_<hostname>.<filestamp>
 * ntpkey_cert_<hostname> (RSA or DSA) link
 *      X509v3 certificate using RSA or DSA public keys and signatures.
 *      XXX is a code identifying the message digest and signature
 *      encryption algorithm
 *
 * Available digest/signature schemes
 *
 * RSA: RSA-MD2, RSA-MD5, RSA-SHA, RSA-SHA1, RSA-MDC2, EVP-RIPEMD160
 * DSA: DSA-SHA, DSA-SHA1
 *
 * Note: Once in a while because of some statistical fluke this program
 * fails to generate and verify some cryptographic data, as indicated by
 * exit status -1. In this case simply run the program again. If the
 * program does complete with return code 0, the data are correct as
 * verified.
 *
 * These cryptographic routines are characterized by the prime modulus
 * size in bits. The default value of 512 bits is a compromise between
 * cryptographic strength and computing time and is ordinarily
 * considered adequate for this application. The routines have been
 * tested with sizes of 256, 512, 1024 and 2048 bits. Not all message
 * digest and signature encryption schemes work with sizes less than 512
 * bits. The computing time for sizes greater than 2048 bits is
 * prohibitive on all but the fastest processors. An UltraSPARC Blade
 * 1000 took something over nine minutes to generate and verify the
 * values with size 2048. An old SPARC IPC would take a week.
 *
 * The OpenSSL library used by this program expects a random seed file.
 * As described in the OpenSSL documentation, the file name defaults to
 * first the RANDFILE environment variable in the user's home directory
 * and then .rnd in the user's home directory.
 */
#ifdef HAVE_CONFIG_H
# include <config.h>
#endif
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/time.h>
#if HAVE_SYS_TYPES_H
# include <sys/types.h>
#endif
#include "ntp_types.h"
#include "ntp_random.h"
#include "l_stdlib.h"

#include "ntp-keygen-opts.h"

#ifdef SYS_WINNT
extern  int     ntp_getopt      P((int, char **, const char *));
#define getopt ntp_getopt
#define optarg ntp_optarg
#endif

#ifdef OPENSSL
#include "openssl/bn.h"
#include "openssl/evp.h"
#include "openssl/err.h"
#include "openssl/rand.h"
#include "openssl/pem.h"
#include "openssl/x509v3.h"
#include <openssl/objects.h>
#endif /* OPENSSL */

/*
 * Cryptodefines
 */
#define MD5KEYS         16      /* number of MD5 keys generated */
#define JAN_1970        ULONG_CONST(2208988800) /* NTP seconds */
#define YEAR            ((long)60*60*24*365) /* one year in seconds */
#define MAXFILENAME     256     /* max file name length */
#define MAXHOSTNAME     256     /* max host name length */
#ifdef OPENSSL
#define PLEN            512     /* default prime modulus size (bits) */

/*
 * Strings used in X509v3 extension fields
 */
#define KEY_USAGE               "digitalSignature,keyCertSign"
#define BASIC_CONSTRAINTS       "critical,CA:TRUE"
#define EXT_KEY_PRIVATE         "private"
#define EXT_KEY_TRUST           "trustRoot"
#endif /* OPENSSL */

/*
 * Prototypes
 */
FILE    *fheader        P((const char *, const char *));
void    fslink          P((const char *, const char *));
int     gen_md5         P((char *));
#ifdef OPENSSL
EVP_PKEY *gen_rsa       P((char *));
EVP_PKEY *gen_dsa       P((char *));
EVP_PKEY *gen_iff       P((char *));
EVP_PKEY *gen_gqpar     P((char *));
EVP_PKEY *gen_gqkey     P((char *, EVP_PKEY *));
EVP_PKEY *gen_mv        P((char *));
int     x509            P((EVP_PKEY *, const EVP_MD *, char *, char *));
void    cb              P((int, int, void *));
EVP_PKEY *genkey        P((char *, char *));
u_long  asn2ntp         P((ASN1_TIME *));
#endif /* OPENSSL */

/*
 * Program variables
 */
extern char *optarg;            /* command line argument */
int     debug = 0;              /* debug, not de bug */
int     rval;                   /* return status */
#ifdef OPENSSL
u_int   modulus = PLEN;         /* prime modulus size (bits) */
#endif
int     nkeys = 0;              /* MV keys */
time_t  epoch;                  /* Unix epoch (seconds) since 1970 */
char    *hostname;              /* host name (subject name) */
char    *trustname;             /* trusted host name (issuer name) */
char    filename[MAXFILENAME + 1]; /* file name */
char    *passwd1 = NULL;        /* input private key password */
char    *passwd2 = NULL;        /* output private key password */
#ifdef OPENSSL
long    d0, d1, d2, d3;         /* callback counters */
#endif /* OPENSSL */

#ifdef SYS_WINNT
BOOL init_randfile();

/*
 * Don't try to follow symbolic links
 */
int
readlink(char * link, char * file, int len) {
        return (-1);
}
/*
 * Don't try to create a symbolic link for now.
 * Just move the file to the name you need.
 */
int
symlink(char *filename, char *linkname) {
        DeleteFile(linkname);
        MoveFile(filename, linkname);
        return 0;
}
void
InitWin32Sockets() {
        WORD wVersionRequested;
        WSADATA wsaData;
        wVersionRequested = MAKEWORD(2,0);
        if (WSAStartup(wVersionRequested, &wsaData))
        {
                fprintf(stderr, "No useable winsock.dll");
                exit(1);
        }
}
#endif /* SYS_WINNT */

/*
 * Main program
 */
int
main(
        int     argc,           /* command line options */
        char    **argv
        )
{
        struct timeval tv;      /* initialization vector */
        int     md5key = 0;     /* generate MD5 keys */
#ifdef OPENSSL
        X509    *cert = NULL;   /* X509 certificate */
        EVP_PKEY *pkey_host = NULL; /* host key */
        EVP_PKEY *pkey_sign = NULL; /* sign key */
        EVP_PKEY *pkey_iff = NULL; /* IFF parameters */
        EVP_PKEY *pkey_gq = NULL; /* GQ parameters */
        EVP_PKEY *pkey_mv = NULL; /* MV parameters */
        int     hostkey = 0;    /* generate RSA keys */
        int     iffkey = 0;     /* generate IFF parameters */
        int     gqpar = 0;      /* generate GQ parameters */
        int     gqkey = 0;      /* update GQ keys */
        int     mvpar = 0;      /* generate MV parameters */
        int     mvkey = 0;      /* update MV keys */
        char    *sign = NULL;   /* sign key */
        EVP_PKEY *pkey = NULL;  /* temp key */
        const EVP_MD *ectx;     /* EVP digest */
        char    pathbuf[MAXFILENAME + 1];
        const char *scheme = NULL; /* digest/signature scheme */
        char    *exten = NULL;  /* private extension */
        char    *grpkey = NULL; /* identity extension */
        int     nid;            /* X509 digest/signature scheme */
        FILE    *fstr = NULL;   /* file handle */
        u_int   temp;
#define iffsw   HAVE_OPT(ID_KEY)
#endif /* OPENSSL */
        char    hostbuf[MAXHOSTNAME + 1];

#ifdef SYS_WINNT
        /* Initialize before OpenSSL checks */
        InitWin32Sockets();
        if(!init_randfile())
                fprintf(stderr, "Unable to initialize .rnd file\n");
#endif

#ifdef OPENSSL
        /*
         * OpenSSL version numbers: MNNFFPPS: major minor fix patch status
         * We match major, minor, fix and status (not patch)
         */
        if ((SSLeay() ^ OPENSSL_VERSION_NUMBER) & ~0xff0L) {
                fprintf(stderr,
                    "OpenSSL version mismatch. Built against %lx, you have %lx\n",
                    (long)OPENSSL_VERSION_NUMBER, SSLeay());
                return (-1);

        } else {
                fprintf(stderr,
                    "Using OpenSSL version %lx\n", SSLeay());
        }
#endif /* OPENSSL */

        /*
         * Process options, initialize host name and timestamp.
         */
        gethostname(hostbuf, MAXHOSTNAME);
        hostname = hostbuf;
#ifdef OPENSSL
        trustname = hostbuf;
        passwd1 = hostbuf;
#endif
#ifndef SYS_WINNT
        gettimeofday(&tv, 0);
#else
        gettimeofday(&tv);
#endif
        epoch = tv.tv_sec;
        rval = 0;

        {
                int optct = optionProcess(&ntp_keygenOptions, argc, argv);
                argc -= optct;
                argv += optct;
        }

#ifdef OPENSSL
        if (HAVE_OPT( CERTIFICATE ))
            scheme = OPT_ARG( CERTIFICATE );
#endif

        debug = DESC(DEBUG_LEVEL).optOccCt;

#ifdef OPENSSL
        if (HAVE_OPT( GQ_PARAMS ))
            gqpar++;

        if (HAVE_OPT( GQ_KEYS ))
            gqkey++;

        if (HAVE_OPT( HOST_KEY ))
            hostkey++;

        if (HAVE_OPT( IFFKEY ))
            iffkey++;

        if (HAVE_OPT( ISSUER_NAME ))
                trustname = (char *)OPT_ARG( ISSUER_NAME );
#endif

        if (HAVE_OPT( MD5KEY ))
            md5key++;

#ifdef OPENSSL
        if (HAVE_OPT( MODULUS ))
            modulus = OPT_VALUE_MODULUS;

        if (HAVE_OPT( PVT_CERT ))
            exten = EXT_KEY_PRIVATE;

        if (HAVE_OPT( PVT_PASSWD ))
                passwd2 = (char *)OPT_ARG( PVT_PASSWD );

        if (HAVE_OPT( GET_PVT_PASSWD ))
                passwd1 = (char *)OPT_ARG( GET_PVT_PASSWD );

        if (HAVE_OPT( SIGN_KEY ))
                sign = (char *)OPT_ARG( SIGN_KEY );

        if (HAVE_OPT( SUBJECT_NAME ))
                hostname = (char *)OPT_ARG( SUBJECT_NAME );

        if (HAVE_OPT( TRUSTED_CERT ))
            exten = EXT_KEY_TRUST;

        if (HAVE_OPT( MV_PARAMS )) {
                mvpar++;
                nkeys = OPT_VALUE_MV_PARAMS;
        }

        if (HAVE_OPT( MV_KEYS )) {
                mvkey++;
                nkeys = OPT_VALUE_MV_KEYS;
        }
#endif

        if (passwd1 != NULL && passwd2 == NULL)
                passwd2 = passwd1;
#ifdef OPENSSL
        /*
         * Seed random number generator and grow weeds.
         */
        ERR_load_crypto_strings();
        OpenSSL_add_all_algorithms();
        if (RAND_file_name(pathbuf, MAXFILENAME) == NULL) {
                fprintf(stderr, "RAND_file_name %s\n",
                    ERR_error_string(ERR_get_error(), NULL));
                return (-1);
        }
        temp = RAND_load_file(pathbuf, -1);
        if (temp == 0) {
                fprintf(stderr,
                    "RAND_load_file %s not found or empty\n", pathbuf);
                return (-1);
        }
        fprintf(stderr,
            "Random seed file %s %u bytes\n", pathbuf, temp);
        RAND_add(&epoch, sizeof(epoch), 4.0);
#endif

        /*
         * Generate new parameters and keys as requested. These replace
         * any values already generated.
         */
        if (md5key)
                gen_md5("MD5");
#ifdef OPENSSL
        if (hostkey)
                pkey_host = genkey("RSA", "host");
        if (sign != NULL)
                pkey_sign = genkey(sign, "sign");
        if (iffkey)
                pkey_iff = gen_iff("iff");
        if (gqpar)
                pkey_gq = gen_gqpar("gq");
        if (mvpar)
                pkey_mv = gen_mv("mv");

        /*
         * If there is no new host key, look for an existing one. If not
         * found, create it.
         */
        while (pkey_host == NULL && rval == 0 && !HAVE_OPT(ID_KEY)) {
                sprintf(filename, "ntpkey_host_%s", hostname);
                if ((fstr = fopen(filename, "r")) != NULL) {
                        pkey_host = PEM_read_PrivateKey(fstr, NULL,
                            NULL, passwd1);
                        fclose(fstr);
                        readlink(filename, filename,  sizeof(filename));
                        if (pkey_host == NULL) {
                                fprintf(stderr, "Host key\n%s\n",
                                    ERR_error_string(ERR_get_error(),
                                    NULL));
                                rval = -1;
                        } else {
                                fprintf(stderr,
                                    "Using host key %s\n", filename);
                        }
                        break;

                } else if ((pkey_host = genkey("RSA", "host")) ==
                    NULL) {
                        rval = -1;
                        break;
                }
        }

        /*
         * If there is no new sign key, look for an existing one. If not
         * found, use the host key instead.
         */
        pkey = pkey_sign;
        while (pkey_sign == NULL && rval == 0 && !HAVE_OPT(ID_KEY)) {
                sprintf(filename, "ntpkey_sign_%s", hostname);
                if ((fstr = fopen(filename, "r")) != NULL) {
                        pkey_sign = PEM_read_PrivateKey(fstr, NULL,
                            NULL, passwd1);
                        fclose(fstr);
                        readlink(filename, filename, sizeof(filename));
                        if (pkey_sign == NULL) {
                                fprintf(stderr, "Sign key\n%s\n",
                                    ERR_error_string(ERR_get_error(),
                                    NULL));
                                rval = -1;
                        } else {
                                fprintf(stderr, "Using sign key %s\n",
                                    filename);
                        }
                        break;
                } else {
                        pkey = pkey_host;
                        fprintf(stderr, "Using host key as sign key\n");
                        break;
                }
        }

        /*
         * If there is no new IFF file, look for an existing one.
         */
        if (pkey_iff == NULL && rval == 0) {
                sprintf(filename, "ntpkey_iff_%s", hostname);
                if ((fstr = fopen(filename, "r")) != NULL) {
                        pkey_iff = PEM_read_PrivateKey(fstr, NULL,
                            NULL, passwd1);
                        fclose(fstr);
                        readlink(filename, filename, sizeof(filename));
                        if (pkey_iff == NULL) {
                                fprintf(stderr, "IFF parameters\n%s\n",
                                    ERR_error_string(ERR_get_error(),
                                    NULL));
                                rval = -1;
                        } else {
                                fprintf(stderr,
                                    "Using IFF parameters %s\n",
                                    filename);
                        }
                }
        }

        /*
         * If there is no new GQ file, look for an existing one.
         */
        if (pkey_gq == NULL && rval == 0 && !HAVE_OPT(ID_KEY)) {
                sprintf(filename, "ntpkey_gq_%s", hostname);
                if ((fstr = fopen(filename, "r")) != NULL) {
                        pkey_gq = PEM_read_PrivateKey(fstr, NULL, NULL,
                            passwd1);
                        fclose(fstr);
                        readlink(filename, filename, sizeof(filename));
                        if (pkey_gq == NULL) {
                                fprintf(stderr, "GQ parameters\n%s\n",
                                    ERR_error_string(ERR_get_error(),
                                    NULL));
                                rval = -1;
                        } else {
                                fprintf(stderr,
                                    "Using GQ parameters %s\n",
                                    filename);
                        }
                }
        }

        /*
         * If there is a GQ parameter file, create GQ private/public
         * keys and extract the public key for the certificate.
         */
        if (pkey_gq != NULL && rval == 0) {
                gen_gqkey("gq", pkey_gq);
                grpkey = BN_bn2hex(pkey_gq->pkey.rsa->q);
        }

        /*
         * Generate a X509v3 certificate.
         */
        while (scheme == NULL && rval == 0 && !HAVE_OPT(ID_KEY)) {
                sprintf(filename, "ntpkey_cert_%s", hostname);
                if ((fstr = fopen(filename, "r")) != NULL) {
                        cert = PEM_read_X509(fstr, NULL, NULL, NULL);
                        fclose(fstr);
                        readlink(filename, filename, sizeof(filename));
                        if (cert == NULL) {
                                fprintf(stderr, "Cert \n%s\n",
                                    ERR_error_string(ERR_get_error(),
                                    NULL));
                                rval = -1;
                        } else {
                                nid = OBJ_obj2nid(
                                 cert->cert_info->signature->algorithm);
                                scheme = OBJ_nid2sn(nid);
                                fprintf(stderr,
                                    "Using scheme %s from %s\n", scheme,
                                     filename);
                                break;
                        }
                }
                scheme = "RSA-MD5";
        }
        if (pkey != NULL && rval == 0 && !HAVE_OPT(ID_KEY)) {
                ectx = EVP_get_digestbyname(scheme);
                if (ectx == NULL) {
                        fprintf(stderr,
                            "Invalid digest/signature combination %s\n",
                            scheme);
                        rval = -1;
                } else {
                        x509(pkey, ectx, grpkey, exten);
                }
        }

        /*
         * Write the IFF client parameters and keys as a DSA private key
         * encoded in PEM. Note the private key is obscured.
         */
        if (pkey_iff != NULL && rval == 0 && HAVE_OPT(ID_KEY)) {
                DSA     *dsa;
                char    *sptr;
                char    *tld;

                sptr = strrchr(filename, '.');
                tld = malloc(strlen(sptr));     /* we have an extra byte ... */
                strcpy(tld, 1+sptr);            /* ... see? */
                sprintf(filename, "ntpkey_IFFkey_%s.%s", trustname,
                    tld);
                free(tld);
                fprintf(stderr, "Writing new IFF key %s\n", filename);
                fprintf(stdout, "# %s\n# %s", filename, ctime(&epoch));
                dsa = pkey_iff->pkey.dsa;
                BN_copy(dsa->priv_key, BN_value_one());
                pkey = EVP_PKEY_new();
                EVP_PKEY_assign_DSA(pkey, dsa);
                PEM_write_PrivateKey(stdout, pkey, passwd2 ?
                    EVP_des_cbc() : NULL, NULL, 0, NULL, passwd2);
                fclose(stdout);
                if (debug)
                        DSA_print_fp(stdout, dsa, 0);
        }

        /*
         * Return the marbles.
         */
        if (grpkey != NULL)
                OPENSSL_free(grpkey);
        if (pkey_host != NULL)
                EVP_PKEY_free(pkey_host);
        if (pkey_sign != NULL)
                EVP_PKEY_free(pkey_sign);
        if (pkey_iff != NULL)
                EVP_PKEY_free(pkey_iff);
        if (pkey_gq != NULL)
                EVP_PKEY_free(pkey_gq);
        if (pkey_mv != NULL)
                EVP_PKEY_free(pkey_mv);
#endif /* OPENSSL */
        return (rval);
}


#if 0
/*
 * Generate random MD5 key with password.
 */
int
gen_md5(
        char    *id             /* file name id */
        )
{
        BIGNUM  *key;
        BIGNUM  *keyid;
        FILE    *str;
        u_char  bin[16];

        fprintf(stderr, "Generating MD5 keys...\n");
        str = fheader("MD5key", hostname);
        keyid = BN_new(); key = BN_new();
        BN_rand(keyid, 16, -1, 0);
        BN_rand(key, 128, -1, 0);
        BN_bn2bin(key, bin);
        PEM_write_fp(str, MD5, NULL, bin);
        fclose(str);
        fslink(id, hostname);
        return (1);
}


#else
/*
 * Generate semi-random MD5 keys compatible with NTPv3 and NTPv4
 */
int
gen_md5(
        char    *id             /* file name id */
        )
{
        u_char  md5key[16];     /* MD5 key */
        FILE    *str;
        u_int   temp = 0;       /* Initialize to prevent warnings during compile */
        int     i, j;

        fprintf(stderr, "Generating MD5 keys...\n");
        str = fheader("MD5key", hostname);
        ntp_srandom(epoch);
        for (i = 1; i <= MD5KEYS; i++) {
                for (j = 0; j < 16; j++) {
                        while (1) {
                                temp = ntp_random() & 0xff;
                                if (temp == '#')
                                        continue;
                                if (temp > 0x20 && temp < 0x7f)
                                        break;
                        }
                        md5key[j] = (u_char)temp;
                }
                md5key[15] = '\0';
                fprintf(str, "%2d MD5 %16s      # MD5 key\n", i,
                    md5key);
        }
        fclose(str);
        fslink(id, hostname);
        return (1);
}
#endif /* OPENSSL */


#ifdef OPENSSL
/*
 * Generate RSA public/private key pair
 */
EVP_PKEY *                      /* public/private key pair */
gen_rsa(
        char    *id             /* file name id */
        )
{
        EVP_PKEY *pkey;         /* private key */
        RSA     *rsa;           /* RSA parameters and key pair */
        FILE    *str;

        fprintf(stderr, "Generating RSA keys (%d bits)...\n", modulus);
        rsa = RSA_generate_key(modulus, 3, cb, "RSA");
        fprintf(stderr, "\n");
        if (rsa == NULL) {
                fprintf(stderr, "RSA generate keys fails\n%s\n",
                    ERR_error_string(ERR_get_error(), NULL));
                rval = -1;
                return (NULL);
        }

        /*
         * For signature encryption it is not necessary that the RSA
         * parameters be strictly groomed and once in a while the
         * modulus turns out to be non-prime. Just for grins, we check
         * the primality.
         */
        if (!RSA_check_key(rsa)) {
                fprintf(stderr, "Invalid RSA key\n%s\n",
                    ERR_error_string(ERR_get_error(), NULL));
                RSA_free(rsa);
                rval = -1;
                return (NULL);
        }

        /*
         * Write the RSA parameters and keys as a RSA private key
         * encoded in PEM.
         */
        str = fheader("RSAkey", hostname);
        pkey = EVP_PKEY_new();
        EVP_PKEY_assign_RSA(pkey, rsa);
        PEM_write_PrivateKey(str, pkey, passwd2 ? EVP_des_cbc() : NULL,
            NULL, 0, NULL, passwd2);
        fclose(str);
        if (debug)
                RSA_print_fp(stdout, rsa, 0);
        fslink(id, hostname);
        return (pkey);
}

 
/*
 * Generate DSA public/private key pair
 */
EVP_PKEY *                      /* public/private key pair */
gen_dsa(
        char    *id             /* file name id */
        )
{
        EVP_PKEY *pkey;         /* private key */
        DSA     *dsa;           /* DSA parameters */
        u_char  seed[20];       /* seed for parameters */
        FILE    *str;

        /*
         * Generate DSA parameters.
         */
        fprintf(stderr,
            "Generating DSA parameters (%d bits)...\n", modulus);
        RAND_bytes(seed, sizeof(seed));
        dsa = DSA_generate_parameters(modulus, seed, sizeof(seed), NULL,
            NULL, cb, "DSA");
        fprintf(stderr, "\n");
        if (dsa == NULL) {
                fprintf(stderr, "DSA generate parameters fails\n%s\n",
                    ERR_error_string(ERR_get_error(), NULL));
                rval = -1;
                return (NULL);
        }

        /*
         * Generate DSA keys.
         */
        fprintf(stderr, "Generating DSA keys (%d bits)...\n", modulus);
        if (!DSA_generate_key(dsa)) {
                fprintf(stderr, "DSA generate keys fails\n%s\n",
                    ERR_error_string(ERR_get_error(), NULL));
                DSA_free(dsa);
                rval = -1;
                return (NULL);
        }

        /*
         * Write the DSA parameters and keys as a DSA private key
         * encoded in PEM.
         */
        str = fheader("DSAkey", hostname);
        pkey = EVP_PKEY_new();
        EVP_PKEY_assign_DSA(pkey, dsa);
        PEM_write_PrivateKey(str, pkey, passwd2 ? EVP_des_cbc() : NULL,
            NULL, 0, NULL, passwd2);
        fclose(str);
        if (debug)
                DSA_print_fp(stdout, dsa, 0);
        fslink(id, hostname);
        return (pkey);
}


/*
 * Generate Schnorr (IFF) parameters and keys
 *
 * The Schnorr (IFF)identity scheme is intended for use when
 * certificates are generated by some other trusted certificate
 * authority and the parameters cannot be conveyed in the certificate
 * itself. For this purpose, new generations of IFF values must be
 * securely transmitted to all members of the group before use. There
 * are two kinds of files: server/client files that include private and
 * public parameters and client files that include only public
 * parameters. The scheme is self contained and independent of new
 * generations of host keys, sign keys and certificates.
 *
 * The IFF values hide in a DSA cuckoo structure which uses the same
 * parameters. The values are used by an identity scheme based on DSA
 * cryptography and described in Stimson p. 285. The p is a 512-bit
 * prime, g a generator of Zp* and q a 160-bit prime that divides p - 1
 * and is a qth root of 1 mod p; that is, g^q = 1 mod p. The TA rolls a
 * private random group key b (0 < b < q), then computes public
 * v = g^(q - a). All values except the group key are known to all group
 * members; the group key is known to the group servers, but not the
 * group clients. Alice challenges Bob to confirm identity using the
 * protocol described below.
 */
EVP_PKEY *                      /* DSA cuckoo nest */
gen_iff(
        char    *id             /* file name id */
        )
{
        EVP_PKEY *pkey;         /* private key */
        DSA     *dsa;           /* DSA parameters */
        u_char  seed[20];       /* seed for parameters */
        BN_CTX  *ctx;           /* BN working space */
        BIGNUM  *b, *r, *k, *u, *v, *w; /* BN temp */
        FILE    *str;
        u_int   temp;

        /*
         * Generate DSA parameters for use as IFF parameters.
         */
        fprintf(stderr, "Generating IFF parameters (%d bits)...\n",
            modulus);
        RAND_bytes(seed, sizeof(seed));
        dsa = DSA_generate_parameters(modulus, seed, sizeof(seed), NULL,
            NULL, cb, "IFF");
        fprintf(stderr, "\n");
        if (dsa == NULL) {
                fprintf(stderr, "DSA generate parameters fails\n%s\n",
                    ERR_error_string(ERR_get_error(), NULL));
                rval = -1;
                return (NULL);;
        }

        /*
         * Generate the private and public keys. The DSA parameters and
         * these keys are distributed to all members of the group.
         */
        fprintf(stderr, "Generating IFF keys (%d bits)...\n", modulus);
        b = BN_new(); r = BN_new(); k = BN_new();
        u = BN_new(); v = BN_new(); w = BN_new(); ctx = BN_CTX_new();
        BN_rand(b, BN_num_bits(dsa->q), -1, 0); /* a */
        BN_mod(b, b, dsa->q, ctx);
        BN_sub(v, dsa->q, b);
        BN_mod_exp(v, dsa->g, v, dsa->p, ctx); /* g^(q - b) mod p */
        BN_mod_exp(u, dsa->g, b, dsa->p, ctx);  /* g^b mod p */
        BN_mod_mul(u, u, v, dsa->p, ctx);
        temp = BN_is_one(u);
        fprintf(stderr,
            "Confirm g^(q - b) g^b = 1 mod p: %s\n", temp == 1 ?
            "yes" : "no");
        if (!temp) {
                BN_free(b); BN_free(r); BN_free(k);
                BN_free(u); BN_free(v); BN_free(w); BN_CTX_free(ctx);
                rval = -1;
                return (NULL);
        }
        dsa->priv_key = BN_dup(b);              /* private key */
        dsa->pub_key = BN_dup(v);               /* public key */

        /*
         * Here is a trial round of the protocol. First, Alice rolls
         * random r (0 < r < q) and sends it to Bob. She needs only
         * modulus q.
         */
        BN_rand(r, BN_num_bits(dsa->q), -1, 0); /* r */
        BN_mod(r, r, dsa->q, ctx);

        /*
         * Bob rolls random k (0 < k < q), computes y = k + b r mod q
         * and x = g^k mod p, then sends (y, x) to Alice. He needs
         * moduli p, q and the group key b.
         */
        BN_rand(k, BN_num_bits(dsa->q), -1, 0); /* k, 0 < k < q  */
        BN_mod(k, k, dsa->q, ctx);
        BN_mod_mul(v, dsa->priv_key, r, dsa->q, ctx); /* b r mod q */
        BN_add(v, v, k);
        BN_mod(v, v, dsa->q, ctx);              /* y = k + b r mod q */
        BN_mod_exp(u, dsa->g, k, dsa->p, ctx);  /* x = g^k mod p */

        /*
         * Alice computes g^y v^r and verifies the result is equal to x.
         * She needs modulus p, generator g, and the public key v, as
         * well as her original r.
         */
        BN_mod_exp(v, dsa->g, v, dsa->p, ctx); /* g^y mod p */
        BN_mod_exp(w, dsa->pub_key, r, dsa->p, ctx); /* v^r */
        BN_mod_mul(v, w, v, dsa->p, ctx);       /* product mod p */
        temp = BN_cmp(u, v);
        fprintf(stderr,
            "Confirm g^k = g^(k + b r) g^(q - b) r: %s\n", temp ==
            0 ? "yes" : "no");
        BN_free(b); BN_free(r); BN_free(k);
        BN_free(u); BN_free(v); BN_free(w); BN_CTX_free(ctx);
        if (temp != 0) {
                DSA_free(dsa);
                rval = -1;
                return (NULL);
        }

        /*
         * Write the IFF server parameters and keys as a DSA private key
         * encoded in PEM.
         *
         * p    modulus p
         * q    modulus q
         * g    generator g
         * priv_key b
         * public_key v
         */
        str = fheader("IFFpar", trustname);
        pkey = EVP_PKEY_new();
        EVP_PKEY_assign_DSA(pkey, dsa);
        PEM_write_PrivateKey(str, pkey, passwd2 ? EVP_des_cbc() : NULL,
            NULL, 0, NULL, passwd2);
        fclose(str);
        if (debug)
                DSA_print_fp(stdout, dsa, 0);
        fslink(id, trustname);
        return (pkey);
}


/*
 * Generate Guillou-Quisquater (GQ) parameters and keys
 *
 * The Guillou-Quisquater (GQ) identity scheme is intended for use when
 * the parameters, keys and certificates are generated by this program.
 * The scheme uses a certificate extension field do convey the public
 * key of a particular group identified by a group key known only to
 * members of the group. The scheme is self contained and independent of
 * new generations of host keys and sign keys.
 *
 * The GQ parameters hide in a RSA cuckoo structure which uses the same
 * parameters. The values are used by an identity scheme based on RSA
 * cryptography and described in Stimson p. 300 (with errors). The 512-
 * bit public modulus is n = p q, where p and q are secret large primes.
 * The TA rolls private random group key b as RSA exponent. These values
 * are known to all group members.
 *
 * When rolling new certificates, a member recomputes the private and
 * public keys. The private key u is a random roll, while the public key
 * is the inverse obscured by the group key v = (u^-1)^b. These values
 * replace the private and public keys normally generated by the RSA
 * scheme. Alice challenges Bob to confirm identity using the protocol
 * described below.
 */
EVP_PKEY *                      /* RSA cuckoo nest */
gen_gqpar(
        char    *id             /* file name id */
        )
{
        EVP_PKEY *pkey;         /* private key */
        RSA     *rsa;           /* GQ parameters */
        BN_CTX  *ctx;           /* BN working space */
        FILE    *str;

        /*
         * Generate RSA parameters for use as GQ parameters.
         */
        fprintf(stderr,
            "Generating GQ parameters (%d bits)...\n", modulus);
        rsa = RSA_generate_key(modulus, 3, cb, "GQ");
        fprintf(stderr, "\n");
        if (rsa == NULL) {
                fprintf(stderr, "RSA generate keys fails\n%s\n",
                    ERR_error_string(ERR_get_error(), NULL));
                rval = -1;
                return (NULL);
        }

        /*
         * Generate the group key b, which is saved in the e member of
         * the RSA structure. These values are distributed to all
         * members of the group, but shielded from all other groups. We
         * don't use all the parameters, but set the unused ones to a
         * small number to minimize the file size.
         */
        ctx = BN_CTX_new();
        BN_rand(rsa->e, BN_num_bits(rsa->n), -1, 0); /* b */
        BN_mod(rsa->e, rsa->e, rsa->n, ctx);
        BN_copy(rsa->d, BN_value_one());
        BN_copy(rsa->p, BN_value_one());
        BN_copy(rsa->q, BN_value_one());
        BN_copy(rsa->dmp1, BN_value_one());
        BN_copy(rsa->dmq1, BN_value_one());
        BN_copy(rsa->iqmp, BN_value_one());

        /*
         * Write the GQ parameters as a RSA private key encoded in PEM.
         * The public and private keys are filled in later.
         *
         * n    modulus n
         * e    group key b
         * (remaining values are not used)
         */
        str = fheader("GQpar", trustname);
        pkey = EVP_PKEY_new();
        EVP_PKEY_assign_RSA(pkey, rsa);
        PEM_write_PrivateKey(str, pkey, passwd2 ? EVP_des_cbc() : NULL,
            NULL, 0, NULL, passwd2);
        fclose(str);
        if (debug)
                RSA_print_fp(stdout, rsa, 0);
        fslink(id, trustname);
        return (pkey);
}


/*
 * Update Guillou-Quisquater (GQ) parameters
 */
EVP_PKEY *                      /* RSA cuckoo nest */
gen_gqkey(
        char    *id,            /* file name id */
        EVP_PKEY *gqpar         /* GQ parameters */
        )
{
        EVP_PKEY *pkey;         /* private key */
        RSA     *rsa;           /* RSA parameters */
        BN_CTX  *ctx;           /* BN working space */
        BIGNUM  *u, *v, *g, *k, *r, *y; /* BN temps */
        FILE    *str;
        u_int   temp;

        /*
         * Generate GQ keys. Note that the group key b is the e member
         * of
         * the GQ parameters.
         */
        fprintf(stderr, "Updating GQ keys (%d bits)...\n", modulus);
        ctx = BN_CTX_new(); u = BN_new(); v = BN_new();
        g = BN_new(); k = BN_new(); r = BN_new(); y = BN_new();

        /*
         * When generating his certificate, Bob rolls random private key
         * u. 
         */
        rsa = gqpar->pkey.rsa;
        BN_rand(u, BN_num_bits(rsa->n), -1, 0); /* u */
        BN_mod(u, u, rsa->n, ctx);
        BN_mod_inverse(v, u, rsa->n, ctx);      /* u^-1 mod n */
        BN_mod_mul(k, v, u, rsa->n, ctx);

        /*
         * Bob computes public key v = (u^-1)^b, which is saved in an
         * extension field on his certificate. We check that u^b v =
         * 1 mod n.
         */
        BN_mod_exp(v, v, rsa->e, rsa->n, ctx);
        BN_mod_exp(g, u, rsa->e, rsa->n, ctx); /* u^b */
        BN_mod_mul(g, g, v, rsa->n, ctx); /* u^b (u^-1)^b */
        temp = BN_is_one(g);
        fprintf(stderr,
            "Confirm u^b (u^-1)^b = 1 mod n: %s\n", temp ? "yes" :
            "no");
        if (!temp) {
                BN_free(u); BN_free(v);
                BN_free(g); BN_free(k); BN_free(r); BN_free(y);
                BN_CTX_free(ctx);
                RSA_free(rsa);
                rval = -1;
                return (NULL);
        }
        BN_copy(rsa->p, u);                     /* private key */
        BN_copy(rsa->q, v);                     /* public key */

        /*
         * Here is a trial run of the protocol. First, Alice rolls
         * random r (0 < r < n) and sends it to Bob. She needs only
         * modulus n from the parameters.
         */
        BN_rand(r, BN_num_bits(rsa->n), -1, 0); /* r */
        BN_mod(r, r, rsa->n, ctx);

        /*
         * Bob rolls random k (0 < k < n), computes y = k u^r mod n and
         * g = k^b mod n, then sends (y, g) to Alice. He needs modulus n
         * from the parameters and his private key u. 
         */
        BN_rand(k, BN_num_bits(rsa->n), -1, 0); /* k */
        BN_mod(k, k, rsa->n, ctx);
        BN_mod_exp(y, rsa->p, r, rsa->n, ctx);  /* u^r mod n */
        BN_mod_mul(y, k, y, rsa->n, ctx);       /* y = k u^r mod n */
        BN_mod_exp(g, k, rsa->e, rsa->n, ctx); /* g = k^b mod n */

        /*
         * Alice computes v^r y^b mod n and verifies the result is equal
         * to g. She needs modulus n, generator g and group key b from
         * the parameters and Bob's public key v = (u^-1)^b from his
         * certificate.
         */
        BN_mod_exp(v, rsa->q, r, rsa->n, ctx);  /* v^r mod n */
        BN_mod_exp(y, y, rsa->e, rsa->n, ctx); /* y^b mod n */
        BN_mod_mul(y, v, y, rsa->n, ctx);       /* v^r y^b mod n */
        temp = BN_cmp(y, g);
        fprintf(stderr, "Confirm g^k = v^r y^b mod n: %s\n", temp == 0 ?
            "yes" : "no");
        BN_CTX_free(ctx); BN_free(u); BN_free(v);
        BN_free(g); BN_free(k); BN_free(r); BN_free(y);
        if (temp != 0) {
                RSA_free(rsa);
                rval = -1;
                return (NULL);
        }

        /*
         * Write the GQ parameters and keys as a RSA private key encoded
         * in PEM.
         *
         * n    modulus n
         * e    group key b
         * p    private key u
         * q    public key (u^-1)^b
         * (remaining values are not used)
         */
        str = fheader("GQpar", trustname);
        pkey = EVP_PKEY_new();
        EVP_PKEY_assign_RSA(pkey, rsa);
        PEM_write_PrivateKey(str, pkey, passwd2 ? EVP_des_cbc() : NULL,
            NULL, 0, NULL, passwd2);
        fclose(str);
        if (debug)
                RSA_print_fp(stdout, rsa, 0);
        fslink(id, trustname);
        return (pkey);
}


/*
 * Generate Mu-Varadharajan (MV) parameters and keys
 *
 * The Mu-Varadharajan (MV) cryptosystem is useful when servers
 * broadcast messages to clients, but clients never send messages to
 * servers. There is one encryption key for the server and a separate
 * decryption key for each client. It operates something like a
 * pay-per-view satellite broadcasting system where the session key is
 * encrypted by the broadcaster and the decryption keys are held in a
 * tamperproof set-top box. We don't use it this way, but read on.
 *
 * The MV parameters and private encryption key hide in a DSA cuckoo
 * structure which uses the same parameters, but generated in a
 * different way. The values are used in an encryption scheme similar to
 * El Gamal cryptography and a polynomial formed from the expansion of
 * product terms (x - x[j]), as described in Mu, Y., and V.
 * Varadharajan: Robust and Secure Broadcasting, Proc. Indocrypt 2001,
 * 223-231. The paper has significant errors and serious omissions.
 *
 * Let q be the product of n distinct primes s'[j] (j = 1...n), where
 * each s'[j] has m significant bits. Let p be a prime p = 2 * q + 1, so
 * that q and each s'[j] divide p - 1 and p has M = n * m + 1
 * significant bits. Let g be a generator of Zp; that is, gcd(g, p - 1)
 * = 1 and g^q = 1 mod p. We do modular arithmetic over Zq and then
 * project into Zp* as exponents of g. Sometimes we have to compute an
 * inverse b^-1 of random b in Zq, but for that purpose we require
 * gcd(b, q) = 1. We expect M to be in the 500-bit range and n
 * relatively small, like 30. Associated with each s'[j] is an element
 * s[j] such that s[j] s'[j] = s'[j] mod q. We find s[j] as the quotient
 * (q + s'[j]) / s'[j]. These are the parameters of the scheme and they
 * are expensive to compute.
 *
 * We set up an instance of the scheme as follows. A set of random
 * values x[j] mod q (j = 1...n), are generated as the zeros of a
 * polynomial of order n. The product terms (x - x[j]) are expanded to
 * form coefficients a[i] mod q (i = 0...n) in powers of x. These are
 * used as exponents of the generator g mod p to generate the private
 * encryption key A. The pair (gbar, ghat) of public server keys and the
 * pairs (xbar[j], xhat[j]) (j = 1...n) of private client keys are used
 * to construct the decryption keys. The devil is in the details.
 *
 * This routine generates a private encryption file including the
 * private encryption key E and public key (gbar, ghat). It then
 * generates decryption files including the private key (xbar[j],
 * xhat[j]) for each client. E is a permutation that encrypts a block
 * y = E x. The jth client computes the inverse permutation E^-1 =
 * gbar^xhat[j] ghat^xbar[j] and decrypts the block x = E^-1 y.
 *
 * The distinguishing characteristic of this scheme is the capability to
 * revoke keys. Included in the calculation of E, gbar and ghat is the
 * product s = prod(s'[j]) (j = 1...n) above. If the factor s'[j] is
 * subsequently removed from the product and E, gbar and ghat
 * recomputed, the jth client will no longer be able to compute E^-1 and
 * thus unable to decrypt the block.
 */
EVP_PKEY *                      /* DSA cuckoo nest */
gen_mv(
        char    *id             /* file name id */
        )
{
        EVP_PKEY *pkey, *pkey1; /* private key */
        DSA     *dsa;           /* DSA parameters */
        DSA     *sdsa;          /* DSA parameters */
        BN_CTX  *ctx;           /* BN working space */
        BIGNUM  **x;            /* polynomial zeros vector */
        BIGNUM  **a;            /* polynomial coefficient vector */
        BIGNUM  **g;            /* public key vector */
        BIGNUM  **s, **s1;      /* private enabling keys */
        BIGNUM  **xbar, **xhat; /* private keys vector */
        BIGNUM  *b;             /* group key */
        BIGNUM  *b1;            /* inverse group key */
        BIGNUM  *ss;            /* enabling key */
        BIGNUM  *biga;          /* master encryption key */
        BIGNUM  *bige;          /* session encryption key */
        BIGNUM  *gbar, *ghat;   /* public key */
        BIGNUM  *u, *v, *w;     /* BN scratch */
        int     i, j, n;
        FILE    *str;
        u_int   temp;
        char    ident[20];

        /*
         * Generate MV parameters.
         *
         * The object is to generate a multiplicative group Zp* modulo a
         * prime p and a subset Zq mod q, where q is the product of n
         * distinct primes s'[j] (j = 1...n) and q divides p - 1. We
         * first generate n distinct primes, which may have to be
         * regenerated later. As a practical matter, it is tough to find
         * more than 31 distinct primes for modulus 512 or 61 primes for
         * modulus 1024. The latter can take several hundred iterations
         * and several minutes on a Sun Blade 1000.
         */
        n = nkeys;
        fprintf(stderr,
            "Generating MV parameters for %d keys (%d bits)...\n", n,
            modulus / n);
        ctx = BN_CTX_new(); u = BN_new(); v = BN_new(); w = BN_new();
        b = BN_new(); b1 = BN_new();
        dsa = DSA_new();
        dsa->p = BN_new();
        dsa->q = BN_new();
        dsa->g = BN_new();
        s = malloc((n + 1) * sizeof(BIGNUM));
        s1 = malloc((n + 1) * sizeof(BIGNUM));
        for (j = 1; j <= n; j++)
                s1[j] = BN_new();
        temp = 0;
        for (j = 1; j <= n; j++) {
                while (1) {
                        fprintf(stderr, "Birthdays %d\r", temp);
                        BN_generate_prime(s1[j], modulus / n, 0, NULL,
                            NULL, NULL, NULL);
                        for (i = 1; i < j; i++) {
                                if (BN_cmp(s1[i], s1[j]) == 0)
                                        break;
                        }
                        if (i == j)
                                break;
                        temp++;
                }
        }
        fprintf(stderr, "Birthday keys rejected %d\n", temp);

        /*
         * Compute the modulus q as the product of the primes. Compute
         * the modulus p as 2 * q + 1 and test p for primality. If p
         * is composite, replace one of the primes with a new distinct
         * one and try again. Note that q will hardly be a secret since
         * we have to reveal p to servers and clients. However,
         * factoring q to find the primes should be adequately hard, as
         * this is the same problem considered hard in RSA. Question: is
         * it as hard to find n small prime factors totalling n bits as
         * it is to find two large prime factors totalling n bits?
         * Remember, the bad guy doesn't know n.
         */
        temp = 0;
        while (1) {
                fprintf(stderr, "Duplicate keys rejected %d\r", ++temp);
                BN_one(dsa->q);
                for (j = 1; j <= n; j++)
                        BN_mul(dsa->q, dsa->q, s1[j], ctx);
                BN_copy(dsa->p, dsa->q);
                BN_add(dsa->p, dsa->p, dsa->p);
                BN_add_word(dsa->p, 1);
                if (BN_is_prime(dsa->p, BN_prime_checks, NULL, ctx,
                    NULL))
                        break;

                j = temp % n + 1;
                while (1) {
                        BN_generate_prime(u, modulus / n, 0, 0, NULL,
                            NULL, NULL);
                        for (i = 1; i <= n; i++) {
                                if (BN_cmp(u, s1[i]) == 0)
                                        break;
                        }
                        if (i > n)
                                break;
                }
                BN_copy(s1[j], u);
        }
        fprintf(stderr, "Duplicate keys rejected %d\n", temp);

        /*
         * Compute the generator g using a random roll such that
         * gcd(g, p - 1) = 1 and g^q = 1. This is a generator of p, not
         * q.
         */
        BN_copy(v, dsa->p);
        BN_sub_word(v, 1);
        while (1) {
                BN_rand(dsa->g, BN_num_bits(dsa->p) - 1, 0, 0);
                BN_mod(dsa->g, dsa->g, dsa->p, ctx);
                BN_gcd(u, dsa->g, v, ctx);
                if (!BN_is_one(u))
                        continue;

                BN_mod_exp(u, dsa->g, dsa->q, dsa->p, ctx);
                if (BN_is_one(u))
                        break;
        }

        /*
         * Compute s[j] such that s[j] * s'[j] = s'[j] for all j. The
         * easy way to do this is to compute q + s'[j] and divide the
         * result by s'[j]. Exercise for the student: prove the
         * remainder is always zero.
         */
        for (j = 1; j <= n; j++) {
                s[j] = BN_new();
                BN_add(s[j], dsa->q, s1[j]);
                BN_div(s[j], u, s[j], s1[j], ctx);
        }

        /*
         * Setup is now complete. Roll random polynomial roots x[j]
         * (0 < x[j] < q) for all j. While it may not be strictly
         * necessary, Make sure each root has no factors in common with
         * q.
         */
        fprintf(stderr,
            "Generating polynomial coefficients for %d roots (%d bits)\n",
            n, BN_num_bits(dsa->q)); 
        x = malloc((n + 1) * sizeof(BIGNUM));
        for (j = 1; j <= n; j++) {
                x[j] = BN_new();
                while (1) {
                        BN_rand(x[j], BN_num_bits(dsa->q), 0, 0);
                        BN_mod(x[j], x[j], dsa->q, ctx);
                        BN_gcd(u, x[j], dsa->q, ctx);
                        if (BN_is_one(u))
                                break;
                }
        }

        /*
         * Generate polynomial coefficients a[i] (i = 0...n) from the
         * expansion of root products (x - x[j]) mod q for all j. The
         * method is a present from Charlie Boncelet.
         */
        a = malloc((n + 1) * sizeof(BIGNUM));
        for (i = 0; i <= n; i++) {
                a[i] = BN_new();
                BN_one(a[i]);
        }
        for (j = 1; j <= n; j++) {
                BN_zero(w);
                for (i = 0; i < j; i++) {
                        BN_copy(u, dsa->q);
                        BN_mod_mul(v, a[i], x[j], dsa->q, ctx);
                        BN_sub(u, u, v);
                        BN_add(u, u, w);
                        BN_copy(w, a[i]);
                        BN_mod(a[i], u, dsa->q, ctx);
                }
        }

        /*
         * Generate g[i] = g^a[i] mod p for all i and the generator g.
         */
        fprintf(stderr, "Generating g[i] parameters\n");
        g = malloc((n + 1) * sizeof(BIGNUM));
        for (i = 0; i <= n; i++) {
                g[i] = BN_new();
                BN_mod_exp(g[i], dsa->g, a[i], dsa->p, ctx);
        }

        /*
         * Verify prod(g[i]^(a[i] x[j]^i)) = 1 for all i, j; otherwise,
         * exit. Note the a[i] x[j]^i exponent is computed mod q, but
         * the g[i] is computed mod p. also note the expression given in
         * the paper is incorrect.
         */
        temp = 1;
        for (j = 1; j <= n; j++) {
                BN_one(u);
                for (i = 0; i <= n; i++) {
                        BN_set_word(v, i);
                        BN_mod_exp(v, x[j], v, dsa->q, ctx);
                        BN_mod_mul(v, v, a[i], dsa->q, ctx);
                        BN_mod_exp(v, dsa->g, v, dsa->p, ctx);
                        BN_mod_mul(u, u, v, dsa->p, ctx);
                }
                if (!BN_is_one(u))
                        temp = 0;
        }
        fprintf(stderr,
            "Confirm prod(g[i]^(x[j]^i)) = 1 for all i, j: %s\n", temp ?
            "yes" : "no");
        if (!temp) {
                rval = -1;
                return (NULL);
        }

        /*
         * Make private encryption key A. Keep it around for awhile,
         * since it is expensive to compute.
         */
        biga = BN_new();
        BN_one(biga);
        for (j = 1; j <= n; j++) {
                for (i = 0; i < n; i++) {
                        BN_set_word(v, i);
                        BN_mod_exp(v, x[j], v, dsa->q, ctx);
                        BN_mod_exp(v, g[i], v, dsa->p, ctx);
                        BN_mod_mul(biga, biga, v, dsa->p, ctx);
                }
        }

        /*
         * Roll private random group key b mod q (0 < b < q), where
         * gcd(b, q) = 1 to guarantee b^1 exists, then compute b^-1
         * mod q. If b is changed, the client keys must be recomputed.
         */
        while (1) {
                BN_rand(b, BN_num_bits(dsa->q), 0, 0);
                BN_mod(b, b, dsa->q, ctx);
                BN_gcd(u, b, dsa->q, ctx);
                if (BN_is_one(u))
                        break;
        }
        BN_mod_inverse(b1, b, dsa->q, ctx);

        /*
         * Make private client keys (xbar[j], xhat[j]) for all j. Note
         * that the keys for the jth client involve s[j], but not s'[j]
         * or the product s = prod(s'[j]) mod q, which is the enabling
         * key.
         */
        xbar = malloc((n + 1) * sizeof(BIGNUM));
        xhat = malloc((n + 1) * sizeof(BIGNUM));
        for (j = 1; j <= n; j++) {
                xbar[j] = BN_new(); xhat[j] = BN_new();
                BN_zero(xbar[j]);
                BN_set_word(v, n);
                for (i = 1; i <= n; i++) {
                        if (i == j)
                                continue;
                        BN_mod_exp(u, x[i], v, dsa->q, ctx);
                        BN_add(xbar[j], xbar[j], u);
                }
                BN_mod_mul(xbar[j], xbar[j], b1, dsa->q, ctx);
                BN_mod_exp(xhat[j], x[j], v, dsa->q, ctx);
                BN_mod_mul(xhat[j], xhat[j], s[j], dsa->q, ctx);
        }

        /*
         * The enabling key is initially q by construction. We can
         * revoke client j by dividing q by s'[j]. The quotient becomes
         * the enabling key s. Note we always have to revoke one key;
         * otherwise, the plaintext and cryptotext would be identical.
         */
        ss = BN_new();
        BN_copy(ss, dsa->q);
        BN_div(ss, u, dsa->q, s1[n], ctx);

        /*
         * Make private server encryption key E = A^s and public server
         * keys gbar = g^s mod p and ghat = g^(s b) mod p. The (gbar,
         * ghat) is the public key provided to the server, which uses it
         * to compute the session encryption key and public key included
         * in its messages. These values must be regenerated if the
         * enabling key is changed.
         */
        bige = BN_new(); gbar = BN_new(); ghat = BN_new();
        BN_mod_exp(bige, biga, ss, dsa->p, ctx);
        BN_mod_exp(gbar, dsa->g, ss, dsa->p, ctx);
        BN_mod_mul(v, ss, b, dsa->q, ctx);
        BN_mod_exp(ghat, dsa->g, v, dsa->p, ctx);

        /*
         * We produce the key media in three steps. The first step is to
         * generate the private values that do not depend on the
         * enabling key. These include the server values p, q, g, b, A
         * and the client values s'[j], xbar[j] and xhat[j] for each j.
         * The p, xbar[j] and xhat[j] values are encoded in private
         * files which are distributed to respective clients. The p, q,
         * g, A and s'[j] values (will be) written to a secret file to
         * be read back later.
         *
         * The secret file (will be) read back at some later time to
         * enable/disable individual keys and generate/regenerate the
         * enabling key s. The p, q, E, gbar and ghat values are written
         * to a secret file to be read back later by the server.
         *
         * The server reads the secret file and rolls the session key
         * k, which is used only once, then computes E^k, gbar^k and
         * ghat^k. The E^k is the session encryption key. The encrypted
         * data, gbar^k and ghat^k are transmtted to clients in an
         * extension field. The client receives the message and computes
         * x = (gbar^k)^xbar[j] (ghat^k)^xhat[j], finds the session
         * encryption key E^k as the inverse x^-1 and decrypts the data.
         */
        BN_copy(dsa->g, bige);
        dsa->priv_key = BN_dup(gbar);
        dsa->pub_key = BN_dup(ghat);

        /*
         * Write the MV server parameters and keys as a DSA private key
         * encoded in PEM.
         *
         * p    modulus p
         * q    modulus q (used only to generate k)
         * g    E mod p
         * priv_key gbar mod p
         * pub_key ghat mod p
         */
        str = fheader("MVpar", trustname);
        pkey = EVP_PKEY_new();
        EVP_PKEY_assign_DSA(pkey, dsa);
        PEM_write_PrivateKey(str, pkey, passwd2 ? EVP_des_cbc() : NULL,
            NULL, 0, NULL, passwd2);
        fclose(str);
        if (debug)
                DSA_print_fp(stdout, dsa, 0);
        fslink(id, trustname);

        /*
         * Write the parameters and private key (xbar[j], xhat[j]) for
         * all j as a DSA private key encoded in PEM. It is used only by
         * the designated recipient(s) who pay a suitably outrageous fee
         * for its use.
         */
        sdsa = DSA_new();
        sdsa->p = BN_dup(dsa->p);
        sdsa->q = BN_dup(BN_value_one());
        sdsa->g = BN_dup(BN_value_one());
        sdsa->priv_key = BN_new();
        sdsa->pub_key = BN_new();
        for (j = 1; j <= n; j++) {
                BN_copy(sdsa->priv_key, xbar[j]);
                BN_copy(sdsa->pub_key, xhat[j]);
                BN_mod_exp(v, dsa->priv_key, sdsa->pub_key, dsa->p,
                    ctx);
                BN_mod_exp(u, dsa->pub_key, sdsa->priv_key, dsa->p,
                    ctx);
                BN_mod_mul(u, u, v, dsa->p, ctx);
                BN_mod_mul(u, u, dsa->g, dsa->p, ctx);
                BN_free(xbar[j]); BN_free(xhat[j]);
                BN_free(x[j]); BN_free(s[j]); BN_free(s1[j]);
                if (!BN_is_one(u)) {
                        fprintf(stderr, "Revoke key %d\n", j);
                        continue;
                }

                /*
                 * Write the client parameters as a DSA private key
                 * encoded in PEM. We don't make links for these.
                 *
                 * p    modulus p
                 * priv_key xbar[j] mod q
                 * pub_key xhat[j] mod q
                 * (remaining values are not used)
                 */
                sprintf(ident, "MVkey%d", j);
                str = fheader(ident, trustname);
                pkey1 = EVP_PKEY_new();
                EVP_PKEY_set1_DSA(pkey1, sdsa);
                PEM_write_PrivateKey(str, pkey1, passwd2 ?
                    EVP_des_cbc() : NULL, NULL, 0, NULL, passwd2);
                fclose(str);
                fprintf(stderr, "ntpkey_%s_%s.%lld\n", ident, trustname,
                    (long long)epoch + JAN_1970);
                if (debug)
                        DSA_print_fp(stdout, sdsa, 0);
                EVP_PKEY_free(pkey1);
        }

        /*
         * Free the countries.
         */
        for (i = 0; i <= n; i++) {
                BN_free(a[i]);
                BN_free(g[i]);
        }
        BN_free(u); BN_free(v); BN_free(w); BN_CTX_free(ctx);
        BN_free(b); BN_free(b1); BN_free(biga); BN_free(bige);
        BN_free(ss); BN_free(gbar); BN_free(ghat);
        DSA_free(sdsa);

        /*
         * Free the world.
         */
        free(x); free(a); free(g); free(s); free(s1);
        free(xbar); free(xhat);
        return (pkey);
}


/*
 * Generate X509v3 scertificate.
 *
 * The certificate consists of the version number, serial number,
 * validity interval, issuer name, subject name and public key. For a
 * self-signed certificate, the issuer name is the same as the subject
 * name and these items are signed using the subject private key. The
 * validity interval extends from the current time to the same time one
 * year hence. For NTP purposes, it is convenient to use the NTP seconds
 * of the current time as the serial number.
 */
int
x509    (
        EVP_PKEY *pkey,         /* generic signature algorithm */
        const EVP_MD *md,       /* generic digest algorithm */
        char    *gqpub,         /* identity extension (hex string) */
        char    *exten          /* private cert extension */
        )
{
        X509    *cert;          /* X509 certificate */
        X509_NAME *subj;        /* distinguished (common) name */
        X509_EXTENSION *ex;     /* X509v3 extension */
        FILE    *str;           /* file handle */
        ASN1_INTEGER *serial;   /* serial number */
        const char *id;         /* digest/signature scheme name */
        char    pathbuf[MAXFILENAME + 1];

        /*
         * Generate X509 self-signed certificate.
         *
         * Set the certificate serial to the NTP seconds for grins. Set
         * the version to 3. Set the subject name and issuer name to the
         * subject name in the request. Set the initial validity to the
         * current time and the final validity one year hence. 
         */
        id = OBJ_nid2sn(md->pkey_type);
        fprintf(stderr, "Generating certificate %s\n", id);
        cert = X509_new();
        X509_set_version(cert, 2L);
        serial = ASN1_INTEGER_new();
        ASN1_INTEGER_set(serial, epoch + JAN_1970);
        X509_set_serialNumber(cert, serial);
        ASN1_INTEGER_free(serial);
        X509_time_adj(X509_get_notBefore(cert), 0L, &epoch);
        X509_time_adj(X509_get_notAfter(cert), YEAR, &epoch);
        subj = X509_get_subject_name(cert);
        X509_NAME_add_entry_by_txt(subj, "commonName", MBSTRING_ASC,
            (unsigned char *) hostname, strlen(hostname), -1, 0);
        subj = X509_get_issuer_name(cert);
        X509_NAME_add_entry_by_txt(subj, "commonName", MBSTRING_ASC,
            (unsigned char *) trustname, strlen(trustname), -1, 0);
        if (!X509_set_pubkey(cert, pkey)) {
                fprintf(stderr, "Assign key fails\n%s\n",
                    ERR_error_string(ERR_get_error(), NULL));
                X509_free(cert);
                rval = -1;
                return (0);
        }

        /*
         * Add X509v3 extensions if present. These represent the minimum
         * set defined in RFC3280 less the certificate_policy extension,
         * which is seriously obfuscated in OpenSSL.
         */
        /*
         * The basic_constraints extension CA:TRUE allows servers to
         * sign client certficitates.
         */
        fprintf(stderr, "%s: %s\n", LN_basic_constraints,
            BASIC_CONSTRAINTS);
        ex = X509V3_EXT_conf_nid(NULL, NULL, NID_basic_constraints,
            BASIC_CONSTRAINTS);
        if (!X509_add_ext(cert, ex, -1)) {
                fprintf(stderr, "Add extension field fails\n%s\n",
                    ERR_error_string(ERR_get_error(), NULL));
                rval = -1;
                return (0);
        }
        X509_EXTENSION_free(ex);

        /*
         * The key_usage extension designates the purposes the key can
         * be used for.
         */
        fprintf(stderr, "%s: %s\n", LN_key_usage, KEY_USAGE);
        ex = X509V3_EXT_conf_nid(NULL, NULL, NID_key_usage, KEY_USAGE);
        if (!X509_add_ext(cert, ex, -1)) {
                fprintf(stderr, "Add extension field fails\n%s\n",
                    ERR_error_string(ERR_get_error(), NULL));
                rval = -1;
                return (0);
        }
        X509_EXTENSION_free(ex);
        /*
         * The subject_key_identifier is used for the GQ public key.
         * This should not be controversial.
         */
        if (gqpub != NULL) {
                fprintf(stderr, "%s\n", LN_subject_key_identifier);
                ex = X509V3_EXT_conf_nid(NULL, NULL,
                    NID_subject_key_identifier, gqpub);
                if (!X509_add_ext(cert, ex, -1)) {
                        fprintf(stderr,
                            "Add extension field fails\n%s\n",
                            ERR_error_string(ERR_get_error(), NULL));
                        rval = -1;
                        return (0);
                }
                X509_EXTENSION_free(ex);
        }

        /*
         * The extended key usage extension is used for special purpose
         * here. The semantics probably do not conform to the designer's
         * intent and will likely change in future.
         * 
         * "trustRoot" designates a root authority
         * "private" designates a private certificate
         */
        if (exten != NULL) {
                fprintf(stderr, "%s: %s\n", LN_ext_key_usage, exten);
                ex = X509V3_EXT_conf_nid(NULL, NULL,
                    NID_ext_key_usage, exten);
                if (!X509_add_ext(cert, ex, -1)) {
                        fprintf(stderr,
                            "Add extension field fails\n%s\n",
                            ERR_error_string(ERR_get_error(), NULL));
                        rval = -1;
                        return (0);
                }
                X509_EXTENSION_free(ex);
        }

        /*
         * Sign and verify.
         */
        X509_sign(cert, pkey, md);
        if (!X509_verify(cert, pkey)) {
                fprintf(stderr, "Verify %s certificate fails\n%s\n", id,
                    ERR_error_string(ERR_get_error(), NULL));
                X509_free(cert);
                rval = -1;
                return (0);
        }

        /*
         * Write the certificate encoded in PEM.
         */
        sprintf(pathbuf, "%scert", id);
        str = fheader(pathbuf, hostname);
        PEM_write_X509(str, cert);
        fclose(str);
        if (debug)
                X509_print_fp(stdout, cert);
        X509_free(cert);
        fslink("cert", hostname);
        return (1);
}

#if 0   /* asn2ntp is not used */
/*
 * asn2ntp - convert ASN1_TIME time structure to NTP time
 */
u_long
asn2ntp (
        ASN1_TIME *asn1time     /* pointer to ASN1_TIME structure */
        )
{
        char    *v;             /* pointer to ASN1_TIME string */
        struct  tm tm;          /* time decode structure time */

        /*
         * Extract time string YYMMDDHHMMSSZ from ASN.1 time structure.
         * Note that the YY, MM, DD fields start with one, the HH, MM,
         * SS fiels start with zero and the Z character should be 'Z'
         * for UTC. Also note that years less than 50 map to years
         * greater than 100. Dontcha love ASN.1?
         */
        if (asn1time->length > 13)
                return (-1);
        v = (char *)asn1time->data;
        tm.tm_year = (v[0] - '0') * 10 + v[1] - '0';
        if (tm.tm_year < 50)
                tm.tm_year += 100;
        tm.tm_mon = (v[2] - '0') * 10 + v[3] - '0' - 1;
        tm.tm_mday = (v[4] - '0') * 10 + v[5] - '0';
        tm.tm_hour = (v[6] - '0') * 10 + v[7] - '0';
        tm.tm_min = (v[8] - '0') * 10 + v[9] - '0';
        tm.tm_sec = (v[10] - '0') * 10 + v[11] - '0';
        tm.tm_wday = 0;
        tm.tm_yday = 0;
        tm.tm_isdst = 0;
        return (mktime(&tm) + JAN_1970);
}
#endif

/*
 * Callback routine
 */
void
cb      (
        int     n1,             /* arg 1 */
        int     n2,             /* arg 2 */
        void    *chr            /* arg 3 */
        )
{
        switch (n1) {
        case 0:
                d0++;
                fprintf(stderr, "%s %d %d %lu\r", (char *)chr, n1, n2,
                    d0);
                break;
        case 1:
                d1++;
                fprintf(stderr, "%s\t\t%d %d %lu\r", (char *)chr, n1,
                    n2, d1);
                break;
        case 2:
                d2++;
                fprintf(stderr, "%s\t\t\t\t%d %d %lu\r", (char *)chr,
                    n1, n2, d2);
                break;
        case 3:
                d3++;
                fprintf(stderr, "%s\t\t\t\t\t\t%d %d %lu\r",
                    (char *)chr, n1, n2, d3);
                break;
        }
}


/*
 * Generate key
 */
EVP_PKEY *                      /* public/private key pair */
genkey(
        char    *type,          /* key type (RSA or DSA) */
        char    *id             /* file name id */
        )
{
        if (type == NULL)
                return (NULL);
        if (strcmp(type, "RSA") == 0)
                return (gen_rsa(id));

        else if (strcmp(type, "DSA") == 0)
                return (gen_dsa(id));

        fprintf(stderr, "Invalid %s key type %s\n", id, type);
        rval = -1;
        return (NULL);
}
#endif /* OPENSSL */


/*
 * Generate file header
 */
FILE *
fheader (
        const char *id,         /* file name id */
        const char *name        /* owner name */
        )
{
        FILE    *str;           /* file handle */

        sprintf(filename, "ntpkey_%s_%s.%lld", id, name, (long long)epoch +
            JAN_1970);
        if ((str = fopen(filename, "w")) == NULL) {
                perror("Write");
                exit (-1);
        }
        fprintf(str, "# %s\n# %s", filename, ctime(&epoch));
        return (str);
}


/*
 * Generate symbolic links
 */
void
fslink(
        const char *id,         /* file name id */
        const char *name        /* owner name */
        )
{
        char    linkname[MAXFILENAME]; /* link name */
        int     temp;

        sprintf(linkname, "ntpkey_%s_%s", id, name);
        remove(linkname);
        temp = symlink(filename, linkname);
        if (temp < 0)
                perror(id);
        fprintf(stderr, "Generating new %s file and link\n", id);
        fprintf(stderr, "%s->%s\n", linkname, filename);
}