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135 .\" ========================================================================
138 .TH pem 3 "2015-06-12" "1.0.1n" "OpenSSL"
139 .\" For nroff, turn off justification. Always turn off hyphenation; it makes
140 .\" way too many mistakes in technical documents.
144 PEM, PEM_read_bio_PrivateKey, PEM_read_PrivateKey, PEM_write_bio_PrivateKey,
145 PEM_write_PrivateKey, PEM_write_bio_PKCS8PrivateKey, PEM_write_PKCS8PrivateKey,
146 PEM_write_bio_PKCS8PrivateKey_nid, PEM_write_PKCS8PrivateKey_nid,
147 PEM_read_bio_PUBKEY, PEM_read_PUBKEY, PEM_write_bio_PUBKEY, PEM_write_PUBKEY,
148 PEM_read_bio_RSAPrivateKey, PEM_read_RSAPrivateKey,
149 PEM_write_bio_RSAPrivateKey, PEM_write_RSAPrivateKey,
150 PEM_read_bio_RSAPublicKey, PEM_read_RSAPublicKey, PEM_write_bio_RSAPublicKey,
151 PEM_write_RSAPublicKey, PEM_read_bio_RSA_PUBKEY, PEM_read_RSA_PUBKEY,
152 PEM_write_bio_RSA_PUBKEY, PEM_write_RSA_PUBKEY, PEM_read_bio_DSAPrivateKey,
153 PEM_read_DSAPrivateKey, PEM_write_bio_DSAPrivateKey, PEM_write_DSAPrivateKey,
154 PEM_read_bio_DSA_PUBKEY, PEM_read_DSA_PUBKEY, PEM_write_bio_DSA_PUBKEY,
155 PEM_write_DSA_PUBKEY, PEM_read_bio_DSAparams, PEM_read_DSAparams,
156 PEM_write_bio_DSAparams, PEM_write_DSAparams, PEM_read_bio_DHparams,
157 PEM_read_DHparams, PEM_write_bio_DHparams, PEM_write_DHparams,
158 PEM_read_bio_X509, PEM_read_X509, PEM_write_bio_X509, PEM_write_X509,
159 PEM_read_bio_X509_AUX, PEM_read_X509_AUX, PEM_write_bio_X509_AUX,
160 PEM_write_X509_AUX, PEM_read_bio_X509_REQ, PEM_read_X509_REQ,
161 PEM_write_bio_X509_REQ, PEM_write_X509_REQ, PEM_write_bio_X509_REQ_NEW,
162 PEM_write_X509_REQ_NEW, PEM_read_bio_X509_CRL, PEM_read_X509_CRL,
163 PEM_write_bio_X509_CRL, PEM_write_X509_CRL, PEM_read_bio_PKCS7, PEM_read_PKCS7,
164 PEM_write_bio_PKCS7, PEM_write_PKCS7, PEM_read_bio_NETSCAPE_CERT_SEQUENCE,
165 PEM_read_NETSCAPE_CERT_SEQUENCE, PEM_write_bio_NETSCAPE_CERT_SEQUENCE,
166 PEM_write_NETSCAPE_CERT_SEQUENCE \- PEM routines
170 .IX Header "SYNOPSIS"
172 \& #include <openssl/pem.h>
174 \& EVP_PKEY *PEM_read_bio_PrivateKey(BIO *bp, EVP_PKEY **x,
175 \& pem_password_cb *cb, void *u);
177 \& EVP_PKEY *PEM_read_PrivateKey(FILE *fp, EVP_PKEY **x,
178 \& pem_password_cb *cb, void *u);
180 \& int PEM_write_bio_PrivateKey(BIO *bp, EVP_PKEY *x, const EVP_CIPHER *enc,
181 \& unsigned char *kstr, int klen,
182 \& pem_password_cb *cb, void *u);
184 \& int PEM_write_PrivateKey(FILE *fp, EVP_PKEY *x, const EVP_CIPHER *enc,
185 \& unsigned char *kstr, int klen,
186 \& pem_password_cb *cb, void *u);
188 \& int PEM_write_bio_PKCS8PrivateKey(BIO *bp, EVP_PKEY *x, const EVP_CIPHER *enc,
189 \& char *kstr, int klen,
190 \& pem_password_cb *cb, void *u);
192 \& int PEM_write_PKCS8PrivateKey(FILE *fp, EVP_PKEY *x, const EVP_CIPHER *enc,
193 \& char *kstr, int klen,
194 \& pem_password_cb *cb, void *u);
196 \& int PEM_write_bio_PKCS8PrivateKey_nid(BIO *bp, EVP_PKEY *x, int nid,
197 \& char *kstr, int klen,
198 \& pem_password_cb *cb, void *u);
200 \& int PEM_write_PKCS8PrivateKey_nid(FILE *fp, EVP_PKEY *x, int nid,
201 \& char *kstr, int klen,
202 \& pem_password_cb *cb, void *u);
204 \& EVP_PKEY *PEM_read_bio_PUBKEY(BIO *bp, EVP_PKEY **x,
205 \& pem_password_cb *cb, void *u);
207 \& EVP_PKEY *PEM_read_PUBKEY(FILE *fp, EVP_PKEY **x,
208 \& pem_password_cb *cb, void *u);
210 \& int PEM_write_bio_PUBKEY(BIO *bp, EVP_PKEY *x);
211 \& int PEM_write_PUBKEY(FILE *fp, EVP_PKEY *x);
213 \& RSA *PEM_read_bio_RSAPrivateKey(BIO *bp, RSA **x,
214 \& pem_password_cb *cb, void *u);
216 \& RSA *PEM_read_RSAPrivateKey(FILE *fp, RSA **x,
217 \& pem_password_cb *cb, void *u);
219 \& int PEM_write_bio_RSAPrivateKey(BIO *bp, RSA *x, const EVP_CIPHER *enc,
220 \& unsigned char *kstr, int klen,
221 \& pem_password_cb *cb, void *u);
223 \& int PEM_write_RSAPrivateKey(FILE *fp, RSA *x, const EVP_CIPHER *enc,
224 \& unsigned char *kstr, int klen,
225 \& pem_password_cb *cb, void *u);
227 \& RSA *PEM_read_bio_RSAPublicKey(BIO *bp, RSA **x,
228 \& pem_password_cb *cb, void *u);
230 \& RSA *PEM_read_RSAPublicKey(FILE *fp, RSA **x,
231 \& pem_password_cb *cb, void *u);
233 \& int PEM_write_bio_RSAPublicKey(BIO *bp, RSA *x);
235 \& int PEM_write_RSAPublicKey(FILE *fp, RSA *x);
237 \& RSA *PEM_read_bio_RSA_PUBKEY(BIO *bp, RSA **x,
238 \& pem_password_cb *cb, void *u);
240 \& RSA *PEM_read_RSA_PUBKEY(FILE *fp, RSA **x,
241 \& pem_password_cb *cb, void *u);
243 \& int PEM_write_bio_RSA_PUBKEY(BIO *bp, RSA *x);
245 \& int PEM_write_RSA_PUBKEY(FILE *fp, RSA *x);
247 \& DSA *PEM_read_bio_DSAPrivateKey(BIO *bp, DSA **x,
248 \& pem_password_cb *cb, void *u);
250 \& DSA *PEM_read_DSAPrivateKey(FILE *fp, DSA **x,
251 \& pem_password_cb *cb, void *u);
253 \& int PEM_write_bio_DSAPrivateKey(BIO *bp, DSA *x, const EVP_CIPHER *enc,
254 \& unsigned char *kstr, int klen,
255 \& pem_password_cb *cb, void *u);
257 \& int PEM_write_DSAPrivateKey(FILE *fp, DSA *x, const EVP_CIPHER *enc,
258 \& unsigned char *kstr, int klen,
259 \& pem_password_cb *cb, void *u);
261 \& DSA *PEM_read_bio_DSA_PUBKEY(BIO *bp, DSA **x,
262 \& pem_password_cb *cb, void *u);
264 \& DSA *PEM_read_DSA_PUBKEY(FILE *fp, DSA **x,
265 \& pem_password_cb *cb, void *u);
267 \& int PEM_write_bio_DSA_PUBKEY(BIO *bp, DSA *x);
269 \& int PEM_write_DSA_PUBKEY(FILE *fp, DSA *x);
271 \& DSA *PEM_read_bio_DSAparams(BIO *bp, DSA **x, pem_password_cb *cb, void *u);
273 \& DSA *PEM_read_DSAparams(FILE *fp, DSA **x, pem_password_cb *cb, void *u);
275 \& int PEM_write_bio_DSAparams(BIO *bp, DSA *x);
277 \& int PEM_write_DSAparams(FILE *fp, DSA *x);
279 \& DH *PEM_read_bio_DHparams(BIO *bp, DH **x, pem_password_cb *cb, void *u);
281 \& DH *PEM_read_DHparams(FILE *fp, DH **x, pem_password_cb *cb, void *u);
283 \& int PEM_write_bio_DHparams(BIO *bp, DH *x);
285 \& int PEM_write_DHparams(FILE *fp, DH *x);
287 \& X509 *PEM_read_bio_X509(BIO *bp, X509 **x, pem_password_cb *cb, void *u);
289 \& X509 *PEM_read_X509(FILE *fp, X509 **x, pem_password_cb *cb, void *u);
291 \& int PEM_write_bio_X509(BIO *bp, X509 *x);
293 \& int PEM_write_X509(FILE *fp, X509 *x);
295 \& X509 *PEM_read_bio_X509_AUX(BIO *bp, X509 **x, pem_password_cb *cb, void *u);
297 \& X509 *PEM_read_X509_AUX(FILE *fp, X509 **x, pem_password_cb *cb, void *u);
299 \& int PEM_write_bio_X509_AUX(BIO *bp, X509 *x);
301 \& int PEM_write_X509_AUX(FILE *fp, X509 *x);
303 \& X509_REQ *PEM_read_bio_X509_REQ(BIO *bp, X509_REQ **x,
304 \& pem_password_cb *cb, void *u);
306 \& X509_REQ *PEM_read_X509_REQ(FILE *fp, X509_REQ **x,
307 \& pem_password_cb *cb, void *u);
309 \& int PEM_write_bio_X509_REQ(BIO *bp, X509_REQ *x);
311 \& int PEM_write_X509_REQ(FILE *fp, X509_REQ *x);
313 \& int PEM_write_bio_X509_REQ_NEW(BIO *bp, X509_REQ *x);
315 \& int PEM_write_X509_REQ_NEW(FILE *fp, X509_REQ *x);
317 \& X509_CRL *PEM_read_bio_X509_CRL(BIO *bp, X509_CRL **x,
318 \& pem_password_cb *cb, void *u);
319 \& X509_CRL *PEM_read_X509_CRL(FILE *fp, X509_CRL **x,
320 \& pem_password_cb *cb, void *u);
321 \& int PEM_write_bio_X509_CRL(BIO *bp, X509_CRL *x);
322 \& int PEM_write_X509_CRL(FILE *fp, X509_CRL *x);
324 \& PKCS7 *PEM_read_bio_PKCS7(BIO *bp, PKCS7 **x, pem_password_cb *cb, void *u);
326 \& PKCS7 *PEM_read_PKCS7(FILE *fp, PKCS7 **x, pem_password_cb *cb, void *u);
328 \& int PEM_write_bio_PKCS7(BIO *bp, PKCS7 *x);
330 \& int PEM_write_PKCS7(FILE *fp, PKCS7 *x);
332 \& NETSCAPE_CERT_SEQUENCE *PEM_read_bio_NETSCAPE_CERT_SEQUENCE(BIO *bp,
333 \& NETSCAPE_CERT_SEQUENCE **x,
334 \& pem_password_cb *cb, void *u);
336 \& NETSCAPE_CERT_SEQUENCE *PEM_read_NETSCAPE_CERT_SEQUENCE(FILE *fp,
337 \& NETSCAPE_CERT_SEQUENCE **x,
338 \& pem_password_cb *cb, void *u);
340 \& int PEM_write_bio_NETSCAPE_CERT_SEQUENCE(BIO *bp, NETSCAPE_CERT_SEQUENCE *x);
342 \& int PEM_write_NETSCAPE_CERT_SEQUENCE(FILE *fp, NETSCAPE_CERT_SEQUENCE *x);
345 .IX Header "DESCRIPTION"
346 The \s-1PEM\s0 functions read or write structures in \s-1PEM\s0 format. In
347 this sense \s-1PEM\s0 format is simply base64 encoded data surrounded
350 For more details about the meaning of arguments see the
351 \&\fB\s-1PEM FUNCTION ARGUMENTS\s0\fR section.
353 Each operation has four functions associated with it. For
354 clarity the term "\fBfoobar\fR functions" will be used to collectively
355 refer to the \fIPEM_read_bio_foobar()\fR, \fIPEM_read_foobar()\fR,
356 \&\fIPEM_write_bio_foobar()\fR and \fIPEM_write_foobar()\fR functions.
358 The \fBPrivateKey\fR functions read or write a private key in
359 \&\s-1PEM\s0 format using an \s-1EVP_PKEY\s0 structure. The write routines use
360 \&\*(L"traditional\*(R" private key format and can handle both \s-1RSA\s0 and \s-1DSA\s0
361 private keys. The read functions can additionally transparently
362 handle PKCS#8 format encrypted and unencrypted keys too.
364 \&\fIPEM_write_bio_PKCS8PrivateKey()\fR and \fIPEM_write_PKCS8PrivateKey()\fR
365 write a private key in an \s-1EVP_PKEY\s0 structure in PKCS#8
366 EncryptedPrivateKeyInfo format using PKCS#5 v2.0 password based encryption
367 algorithms. The \fBcipher\fR argument specifies the encryption algorithm to
368 use: unlike all other \s-1PEM\s0 routines the encryption is applied at the
369 PKCS#8 level and not in the \s-1PEM\s0 headers. If \fBcipher\fR is \s-1NULL\s0 then no
370 encryption is used and a PKCS#8 PrivateKeyInfo structure is used instead.
372 \&\fIPEM_write_bio_PKCS8PrivateKey_nid()\fR and \fIPEM_write_PKCS8PrivateKey_nid()\fR
373 also write out a private key as a PKCS#8 EncryptedPrivateKeyInfo however
374 it uses PKCS#5 v1.5 or PKCS#12 encryption algorithms instead. The algorithm
375 to use is specified in the \fBnid\fR parameter and should be the \s-1NID\s0 of the
376 corresponding \s-1OBJECT IDENTIFIER \s0(see \s-1NOTES\s0 section).
378 The \fB\s-1PUBKEY\s0\fR functions process a public key using an \s-1EVP_PKEY\s0
379 structure. The public key is encoded as a SubjectPublicKeyInfo
382 The \fBRSAPrivateKey\fR functions process an \s-1RSA\s0 private key using an
383 \&\s-1RSA\s0 structure. It handles the same formats as the \fBPrivateKey\fR
384 functions but an error occurs if the private key is not \s-1RSA.\s0
386 The \fBRSAPublicKey\fR functions process an \s-1RSA\s0 public key using an
387 \&\s-1RSA\s0 structure. The public key is encoded using a PKCS#1 RSAPublicKey
390 The \fB\s-1RSA_PUBKEY\s0\fR functions also process an \s-1RSA\s0 public key using
391 an \s-1RSA\s0 structure. However the public key is encoded using a
392 SubjectPublicKeyInfo structure and an error occurs if the public
393 key is not \s-1RSA.\s0
395 The \fBDSAPrivateKey\fR functions process a \s-1DSA\s0 private key using a
396 \&\s-1DSA\s0 structure. It handles the same formats as the \fBPrivateKey\fR
397 functions but an error occurs if the private key is not \s-1DSA.\s0
399 The \fB\s-1DSA_PUBKEY\s0\fR functions process a \s-1DSA\s0 public key using
400 a \s-1DSA\s0 structure. The public key is encoded using a
401 SubjectPublicKeyInfo structure and an error occurs if the public
402 key is not \s-1DSA.\s0
404 The \fBDSAparams\fR functions process \s-1DSA\s0 parameters using a \s-1DSA\s0
405 structure. The parameters are encoded using a Dss-Parms structure
406 as defined in \s-1RFC2459.\s0
408 The \fBDHparams\fR functions process \s-1DH\s0 parameters using a \s-1DH\s0
409 structure. The parameters are encoded using a PKCS#3 DHparameter
412 The \fBX509\fR functions process an X509 certificate using an X509
413 structure. They will also process a trusted X509 certificate but
414 any trust settings are discarded.
416 The \fBX509_AUX\fR functions process a trusted X509 certificate using
419 The \fBX509_REQ\fR and \fBX509_REQ_NEW\fR functions process a PKCS#10
420 certificate request using an X509_REQ structure. The \fBX509_REQ\fR
421 write functions use \fB\s-1CERTIFICATE REQUEST\s0\fR in the header whereas
422 the \fBX509_REQ_NEW\fR functions use \fB\s-1NEW CERTIFICATE REQUEST\s0\fR
423 (as required by some CAs). The \fBX509_REQ\fR read functions will
424 handle either form so there are no \fBX509_REQ_NEW\fR read functions.
426 The \fBX509_CRL\fR functions process an X509 \s-1CRL\s0 using an X509_CRL
429 The \fB\s-1PKCS7\s0\fR functions process a PKCS#7 ContentInfo using a \s-1PKCS7\s0
432 The \fB\s-1NETSCAPE_CERT_SEQUENCE\s0\fR functions process a Netscape Certificate
433 Sequence using a \s-1NETSCAPE_CERT_SEQUENCE\s0 structure.
434 .SH "PEM FUNCTION ARGUMENTS"
435 .IX Header "PEM FUNCTION ARGUMENTS"
436 The \s-1PEM\s0 functions have many common arguments.
438 The \fBbp\fR \s-1BIO\s0 parameter (if present) specifies the \s-1BIO\s0 to read from
441 The \fBfp\fR \s-1FILE\s0 parameter (if present) specifies the \s-1FILE\s0 pointer to
442 read from or write to.
444 The \s-1PEM\s0 read functions all take an argument \fB\s-1TYPE\s0 **x\fR and return
445 a \fB\s-1TYPE\s0 *\fR pointer. Where \fB\s-1TYPE\s0\fR is whatever structure the function
446 uses. If \fBx\fR is \s-1NULL\s0 then the parameter is ignored. If \fBx\fR is not
447 \&\s-1NULL\s0 but \fB*x\fR is \s-1NULL\s0 then the structure returned will be written
448 to \fB*x\fR. If neither \fBx\fR nor \fB*x\fR is \s-1NULL\s0 then an attempt is made
449 to reuse the structure at \fB*x\fR (but see \s-1BUGS\s0 and \s-1EXAMPLES\s0 sections).
450 Irrespective of the value of \fBx\fR a pointer to the structure is always
451 returned (or \s-1NULL\s0 if an error occurred).
453 The \s-1PEM\s0 functions which write private keys take an \fBenc\fR parameter
454 which specifies the encryption algorithm to use, encryption is done
455 at the \s-1PEM\s0 level. If this parameter is set to \s-1NULL\s0 then the private
456 key is written in unencrypted form.
458 The \fBcb\fR argument is the callback to use when querying for the pass
459 phrase used for encrypted \s-1PEM\s0 structures (normally only private keys).
461 For the \s-1PEM\s0 write routines if the \fBkstr\fR parameter is not \s-1NULL\s0 then
462 \&\fBklen\fR bytes at \fBkstr\fR are used as the passphrase and \fBcb\fR is
465 If the \fBcb\fR parameters is set to \s-1NULL\s0 and the \fBu\fR parameter is not
466 \&\s-1NULL\s0 then the \fBu\fR parameter is interpreted as a null terminated string
467 to use as the passphrase. If both \fBcb\fR and \fBu\fR are \s-1NULL\s0 then the
468 default callback routine is used which will typically prompt for the
469 passphrase on the current terminal with echoing turned off.
471 The default passphrase callback is sometimes inappropriate (for example
472 in a \s-1GUI\s0 application) so an alternative can be supplied. The callback
473 routine has the following form:
476 \& int cb(char *buf, int size, int rwflag, void *u);
479 \&\fBbuf\fR is the buffer to write the passphrase to. \fBsize\fR is the maximum
480 length of the passphrase (i.e. the size of buf). \fBrwflag\fR is a flag
481 which is set to 0 when reading and 1 when writing. A typical routine
482 will ask the user to verify the passphrase (for example by prompting
483 for it twice) if \fBrwflag\fR is 1. The \fBu\fR parameter has the same
484 value as the \fBu\fR parameter passed to the \s-1PEM\s0 routine. It allows
485 arbitrary data to be passed to the callback by the application
486 (for example a window handle in a \s-1GUI\s0 application). The callback
487 \&\fBmust\fR return the number of characters in the passphrase or 0 if
490 .IX Header "EXAMPLES"
491 Although the \s-1PEM\s0 routines take several arguments in almost all applications
492 most of them are set to 0 or \s-1NULL.\s0
494 Read a certificate in \s-1PEM\s0 format from a \s-1BIO:\s0
498 \& x = PEM_read_bio_X509(bp, NULL, 0, NULL);
509 \& if (!PEM_read_bio_X509(bp, &x, 0, NULL))
515 Write a certificate to a \s-1BIO:\s0
518 \& if (!PEM_write_bio_X509(bp, x))
524 Write an unencrypted private key to a \s-1FILE\s0 pointer:
527 \& if (!PEM_write_PrivateKey(fp, key, NULL, NULL, 0, 0, NULL))
533 Write a private key (using traditional format) to a \s-1BIO\s0 using
534 triple \s-1DES\s0 encryption, the pass phrase is prompted for:
537 \& if (!PEM_write_bio_PrivateKey(bp, key, EVP_des_ede3_cbc(), NULL, 0, 0, NULL))
543 Write a private key (using PKCS#8 format) to a \s-1BIO\s0 using triple
544 \&\s-1DES\s0 encryption, using the pass phrase \*(L"hello\*(R":
547 \& if (!PEM_write_bio_PKCS8PrivateKey(bp, key, EVP_des_ede3_cbc(), NULL, 0, 0, "hello"))
553 Read a private key from a \s-1BIO\s0 using the pass phrase \*(L"hello\*(R":
556 \& key = PEM_read_bio_PrivateKey(bp, NULL, 0, "hello");
563 Read a private key from a \s-1BIO\s0 using a pass phrase callback:
566 \& key = PEM_read_bio_PrivateKey(bp, NULL, pass_cb, "My Private Key");
573 Skeleton pass phrase callback:
576 \& int pass_cb(char *buf, int size, int rwflag, void *u);
580 \& /* We\*(Aqd probably do something else if \*(Aqrwflag\*(Aq is 1 */
581 \& printf("Enter pass phrase for \e"%s\e"\en", u);
583 \& /* get pass phrase, length \*(Aqlen\*(Aq into \*(Aqtmp\*(Aq */
585 \& len = strlen(tmp);
587 \& if (len <= 0) return 0;
588 \& /* if too long, truncate */
589 \& if (len > size) len = size;
590 \& memcpy(buf, tmp, len);
596 The old \fBPrivateKey\fR write routines are retained for compatibility.
597 New applications should write private keys using the
598 \&\fIPEM_write_bio_PKCS8PrivateKey()\fR or \fIPEM_write_PKCS8PrivateKey()\fR routines
599 because they are more secure (they use an iteration count of 2048 whereas
600 the traditional routines use a count of 1) unless compatibility with older
601 versions of OpenSSL is important.
603 The \fBPrivateKey\fR read routines can be used in all applications because
604 they handle all formats transparently.
606 A frequent cause of problems is attempting to use the \s-1PEM\s0 routines like
611 \& PEM_read_bio_X509(bp, &x, 0, NULL);
614 this is a bug because an attempt will be made to reuse the data at \fBx\fR
615 which is an uninitialised pointer.
616 .SH "PEM ENCRYPTION FORMAT"
617 .IX Header "PEM ENCRYPTION FORMAT"
618 This old \fBPrivateKey\fR routines use a non standard technique for encryption.
620 The private key (or other data) takes the following form:
623 \& \-\-\-\-\-BEGIN RSA PRIVATE KEY\-\-\-\-\-
624 \& Proc\-Type: 4,ENCRYPTED
625 \& DEK\-Info: DES\-EDE3\-CBC,3F17F5316E2BAC89
627 \& ...base64 encoded data...
628 \& \-\-\-\-\-END RSA PRIVATE KEY\-\-\-\-\-
631 The line beginning DEK-Info contains two comma separated pieces of information:
632 the encryption algorithm name as used by \fIEVP_get_cipherbyname()\fR and an 8
633 byte \fBsalt\fR encoded as a set of hexadecimal digits.
635 After this is the base64 encoded encrypted data.
637 The encryption key is determined using \fIEVP_BytesToKey()\fR, using \fBsalt\fR and an
638 iteration count of 1. The \s-1IV\s0 used is the value of \fBsalt\fR and *not* the \s-1IV\s0
639 returned by \fIEVP_BytesToKey()\fR.
642 The \s-1PEM\s0 read routines in some versions of OpenSSL will not correctly reuse
643 an existing structure. Therefore the following:
646 \& PEM_read_bio_X509(bp, &x, 0, NULL);
649 where \fBx\fR already contains a valid certificate, may not work, whereas:
653 \& x = PEM_read_bio_X509(bp, NULL, 0, NULL);
656 is guaranteed to work.
658 .IX Header "RETURN CODES"
659 The read routines return either a pointer to the structure read or \s-1NULL\s0
660 if an error occurred.
662 The write routines return 1 for success or 0 for failure.
664 .IX Header "SEE ALSO"
665 \&\fIEVP_get_cipherbyname\fR\|(3), \fIEVP_BytesToKey\fR\|(3)