release/src/router/nettle/examples/rsa-session.h

   1 /* Session key definitions for the rsa-encrypt and rsa-decrypt programs.
   2  */
   3
   4 #ifndef NETTLE_EXAMPLES_RSA_SESSION_H_INCLUDED
   5 #define NETTLE_EXAMPLES_RSA_SESSION_H_INCLUDED
   6
   7 #include "aes.h"
   8 #include "cbc.h"
   9 #include "hmac.h"
  10
  11 #define RSA_VERSION 1
  12
  13 /* Encryption program using the following file format:
  14
  15      uint32_t version = 1;
  16      uint32_t nsize;
  17      uint8_t x[nsize];
  18      uint8_t encrypted[n];
  19      uint8_t hmac[SHA1_DIGEST_SIZE];
  20
  21    where x is the data
  22
  23      uint32_t version = 1;
  24      uint8_t aes_key[AES_KEY_SIZE];
  25      uint8_t iv[AES_BLOCK_SIZE];
  26      uint8_t hmac_key[SHA1_DIGEST_SIZE];
  27
  28    of size (4 + AES_KEY_SIZE + AES_BLOCK_SIZE + SHA1_DIGEST_SIZE) = 72
  29    bytes, encrypted using rsa-pkcs1.
  30
  31    The cleartext input is encrypted using aes-cbc. The final block is
  32    padded as
  33
  34      | data | random octets | padding length |
  35
  36    where the last octet is the padding length, a number between 1 and
  37    AES_BLOCK_SIZE (inclusive).
  38 */
  39
  40 struct rsa_session
  41 {
  42   struct CBC_CTX(struct aes_ctx, AES_BLOCK_SIZE) aes;
  43   struct hmac_sha1_ctx hmac;
  44   struct yarrow256_ctx yarrow;
  45 };
  46
  47 struct rsa_session_info
  48 {
  49   /* Version followed by aes key, iv and mac key */
  50   uint8_t key[4 + AES_KEY_SIZE + AES_BLOCK_SIZE + SHA1_DIGEST_SIZE];
  51 };
  52
  53 #define SESSION_VERSION(s) ((s)->key)
  54 #define SESSION_AES_KEY(s) ((s)->key + 4)
  55 #define SESSION_IV(s) ((s)->key + 4 + AES_KEY_SIZE)
  56 #define SESSION_HMAC_KEY(s) ((s)->key + 4 + AES_KEY_SIZE + AES_BLOCK_SIZE)
  57
  58 void
  59 rsa_session_set_encrypt_key(struct rsa_session *ctx,
  60                             const struct rsa_session_info *key);
  61
  62 void
  63 rsa_session_set_decrypt_key(struct rsa_session *ctx,
  64                             const struct rsa_session_info *key);
  65
  66 #endif /* NETTLE_EXAMPLES_RSA_SESSION_H_INCLUDED */