doc/man3/PEM_read_bio_PrivateKey.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 pem_password_cb,
   6 PEM_read_bio_PrivateKey_ex, PEM_read_bio_PrivateKey,
   7 PEM_read_PrivateKey_ex, PEM_read_PrivateKey,
   8 PEM_write_bio_PrivateKey_ex, PEM_write_bio_PrivateKey,
   9 PEM_write_bio_PrivateKey_traditional,
  10 PEM_write_PrivateKey_ex, PEM_write_PrivateKey,
  11 PEM_write_bio_PKCS8PrivateKey, PEM_write_PKCS8PrivateKey,
  12 PEM_write_bio_PKCS8PrivateKey_nid, PEM_write_PKCS8PrivateKey_nid,
  13 PEM_read_bio_PUBKEY_ex, PEM_read_bio_PUBKEY,
  14 PEM_read_PUBKEY_ex, PEM_read_PUBKEY,
  15 PEM_write_bio_PUBKEY_ex, PEM_write_bio_PUBKEY,
  16 PEM_write_PUBKEY_ex, PEM_write_PUBKEY,
  17 PEM_read_bio_RSAPrivateKey, PEM_read_RSAPrivateKey,
  18 PEM_write_bio_RSAPrivateKey, PEM_write_RSAPrivateKey,
  19 PEM_read_bio_RSAPublicKey, PEM_read_RSAPublicKey, PEM_write_bio_RSAPublicKey,
  20 PEM_write_RSAPublicKey, PEM_read_bio_RSA_PUBKEY, PEM_read_RSA_PUBKEY,
  21 PEM_write_bio_RSA_PUBKEY, PEM_write_RSA_PUBKEY, PEM_read_bio_DSAPrivateKey,
  22 PEM_read_DSAPrivateKey, PEM_write_bio_DSAPrivateKey, PEM_write_DSAPrivateKey,
  23 PEM_read_bio_DSA_PUBKEY, PEM_read_DSA_PUBKEY, PEM_write_bio_DSA_PUBKEY,
  24 PEM_write_DSA_PUBKEY, PEM_read_bio_Parameters_ex, PEM_read_bio_Parameters,
  25 PEM_write_bio_Parameters, PEM_read_bio_DSAparams, PEM_read_DSAparams,
  26 PEM_write_bio_DSAparams, PEM_write_DSAparams, PEM_read_bio_DHparams,
  27 PEM_read_DHparams, PEM_write_bio_DHparams, PEM_write_DHparams,
  28 PEM_read_bio_X509, PEM_read_X509, PEM_write_bio_X509, PEM_write_X509,
  29 PEM_read_bio_X509_AUX, PEM_read_X509_AUX, PEM_write_bio_X509_AUX,
  30 PEM_write_X509_AUX, PEM_read_bio_X509_REQ, PEM_read_X509_REQ,
  31 PEM_write_bio_X509_REQ, PEM_write_X509_REQ, PEM_write_bio_X509_REQ_NEW,
  32 PEM_write_X509_REQ_NEW, PEM_read_bio_X509_CRL, PEM_read_X509_CRL,
  33 PEM_write_bio_X509_CRL, PEM_write_X509_CRL, PEM_read_bio_PKCS7, PEM_read_PKCS7,
  34 PEM_write_bio_PKCS7, PEM_write_PKCS7 - PEM routines
  35
  36 =head1 SYNOPSIS
  37
  38  #include <openssl/pem.h>
  39
  40  typedef int pem_password_cb(char *buf, int size, int rwflag, void *u);
  41
  42  EVP_PKEY *PEM_read_bio_PrivateKey_ex(BIO *bp, EVP_PKEY **x,
  43                                       pem_password_cb *cb, void *u,
  44                                       OSSL_LIB_CTX *libctx, const char *propq);
  45  EVP_PKEY *PEM_read_bio_PrivateKey(BIO *bp, EVP_PKEY **x,
  46                                    pem_password_cb *cb, void *u);
  47  EVP_PKEY *PEM_read_PrivateKey_ex(FILE *fp, EVP_PKEY **x, pem_password_cb *cb,
  48                                   void *u, OSSL_LIB_CTX *libctx,
  49                                   const char *propq);
  50  EVP_PKEY *PEM_read_PrivateKey(FILE *fp, EVP_PKEY **x,
  51                                pem_password_cb *cb, void *u);
  52  int PEM_write_bio_PrivateKey_ex(BIO *bp, const EVP_PKEY *x,
  53                                  const EVP_CIPHER *enc,
  54                                  unsigned char *kstr, int klen,
  55                                  pem_password_cb *cb, void *u,
  56                                  OSSL_LIB_CTX *libctx, const char *propq);
  57  int PEM_write_bio_PrivateKey(BIO *bp, const EVP_PKEY *x, const EVP_CIPHER *enc,
  58                               unsigned char *kstr, int klen,
  59                               pem_password_cb *cb, void *u);
  60  int PEM_write_bio_PrivateKey_traditional(BIO *bp, EVP_PKEY *x,
  61                                           const EVP_CIPHER *enc,
  62                                           unsigned char *kstr, int klen,
  63                                           pem_password_cb *cb, void *u);
  64  int PEM_write_PrivateKey_ex(FILE *fp, EVP_PKEY *x, const EVP_CIPHER *enc,
  65                              unsigned char *kstr, int klen,
  66                              pem_password_cb *cb, void *u,
  67                              OSSL_LIB_CTX *libctx, const char *propq);
  68  int PEM_write_PrivateKey(FILE *fp, EVP_PKEY *x, const EVP_CIPHER *enc,
  69                           unsigned char *kstr, int klen,
  70                           pem_password_cb *cb, void *u);
  71  int PEM_write_bio_PKCS8PrivateKey(BIO *bp, EVP_PKEY *x, const EVP_CIPHER *enc,
  72                                    char *kstr, int klen,
  73                                    pem_password_cb *cb, void *u);
  74  int PEM_write_PKCS8PrivateKey(FILE *fp, EVP_PKEY *x, const EVP_CIPHER *enc,
  75                                char *kstr, int klen,
  76                                pem_password_cb *cb, void *u);
  77  int PEM_write_bio_PKCS8PrivateKey_nid(BIO *bp, const EVP_PKEY *x, int nid,
  78                                        char *kstr, int klen,
  79                                        pem_password_cb *cb, void *u);
  80  int PEM_write_PKCS8PrivateKey_nid(FILE *fp, const EVP_PKEY *x, int nid,
  81                                    char *kstr, int klen,
  82                                    pem_password_cb *cb, void *u);
  83
  84  EVP_PKEY *PEM_read_bio_PUBKEY_ex(BIO *bp, EVP_PKEY **x,
  85                                   pem_password_cb *cb, void *u,
  86                                   OSSL_LIB_CTX *libctx, const char *propq);
  87  EVP_PKEY *PEM_read_bio_PUBKEY(BIO *bp, EVP_PKEY **x,
  88                                pem_password_cb *cb, void *u);
  89  EVP_PKEY *PEM_read_PUBKEY_ex(FILE *fp, EVP_PKEY **x,
  90                               pem_password_cb *cb, void *u,
  91                               OSSL_LIB_CTX *libctx, const char *propq);
  92  EVP_PKEY *PEM_read_PUBKEY(FILE *fp, EVP_PKEY **x,
  93                            pem_password_cb *cb, void *u);
  94  int PEM_write_bio_PUBKEY_ex(BIO *bp, EVP_PKEY *x,
  95                              OSSL_LIB_CTX *libctx, const char *propq);
  96  int PEM_write_bio_PUBKEY(BIO *bp, EVP_PKEY *x);
  97  int PEM_write_PUBKEY_ex(FILE *fp, EVP_PKEY *x,
  98                          OSSL_LIB_CTX *libctx, const char *propq);
  99  int PEM_write_PUBKEY(FILE *fp, EVP_PKEY *x);
 100
 101  EVP_PKEY *PEM_read_bio_Parameters_ex(BIO *bp, EVP_PKEY **x,
 102                                       OSSL_LIB_CTX *libctx, const char *propq);
 103  EVP_PKEY *PEM_read_bio_Parameters(BIO *bp, EVP_PKEY **x);
 104  int PEM_write_bio_Parameters(BIO *bp, const EVP_PKEY *x);
 105
 106  X509 *PEM_read_bio_X509(BIO *bp, X509 **x, pem_password_cb *cb, void *u);
 107  X509 *PEM_read_X509(FILE *fp, X509 **x, pem_password_cb *cb, void *u);
 108  int PEM_write_bio_X509(BIO *bp, X509 *x);
 109  int PEM_write_X509(FILE *fp, X509 *x);
 110
 111  X509 *PEM_read_bio_X509_AUX(BIO *bp, X509 **x, pem_password_cb *cb, void *u);
 112  X509 *PEM_read_X509_AUX(FILE *fp, X509 **x, pem_password_cb *cb, void *u);
 113  int PEM_write_bio_X509_AUX(BIO *bp, X509 *x);
 114  int PEM_write_X509_AUX(FILE *fp, X509 *x);
 115
 116  X509_REQ *PEM_read_bio_X509_REQ(BIO *bp, X509_REQ **x,
 117                                  pem_password_cb *cb, void *u);
 118  X509_REQ *PEM_read_X509_REQ(FILE *fp, X509_REQ **x,
 119                              pem_password_cb *cb, void *u);
 120  int PEM_write_bio_X509_REQ(BIO *bp, X509_REQ *x);
 121  int PEM_write_X509_REQ(FILE *fp, X509_REQ *x);
 122  int PEM_write_bio_X509_REQ_NEW(BIO *bp, X509_REQ *x);
 123  int PEM_write_X509_REQ_NEW(FILE *fp, X509_REQ *x);
 124
 125  X509_CRL *PEM_read_bio_X509_CRL(BIO *bp, X509_CRL **x,
 126                                  pem_password_cb *cb, void *u);
 127  X509_CRL *PEM_read_X509_CRL(FILE *fp, X509_CRL **x,
 128                              pem_password_cb *cb, void *u);
 129  int PEM_write_bio_X509_CRL(BIO *bp, X509_CRL *x);
 130  int PEM_write_X509_CRL(FILE *fp, X509_CRL *x);
 131
 132  PKCS7 *PEM_read_bio_PKCS7(BIO *bp, PKCS7 **x, pem_password_cb *cb, void *u);
 133  PKCS7 *PEM_read_PKCS7(FILE *fp, PKCS7 **x, pem_password_cb *cb, void *u);
 134  int PEM_write_bio_PKCS7(BIO *bp, PKCS7 *x);
 135  int PEM_write_PKCS7(FILE *fp, PKCS7 *x);
 136
 137 The following functions have been deprecated since OpenSSL 3.0, and can be
 138 hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
 139 see L<openssl_user_macros(7)>:
 140
 141  RSA *PEM_read_bio_RSAPrivateKey(BIO *bp, RSA **x,
 142                                  pem_password_cb *cb, void *u);
 143  RSA *PEM_read_RSAPrivateKey(FILE *fp, RSA **x,
 144                              pem_password_cb *cb, void *u);
 145  int PEM_write_bio_RSAPrivateKey(BIO *bp, RSA *x, const EVP_CIPHER *enc,
 146                                  unsigned char *kstr, int klen,
 147                                  pem_password_cb *cb, void *u);
 148  int PEM_write_RSAPrivateKey(FILE *fp, RSA *x, const EVP_CIPHER *enc,
 149                              unsigned char *kstr, int klen,
 150                              pem_password_cb *cb, void *u);
 151
 152  RSA *PEM_read_bio_RSAPublicKey(BIO *bp, RSA **x,
 153                                 pem_password_cb *cb, void *u);
 154  RSA *PEM_read_RSAPublicKey(FILE *fp, RSA **x,
 155                             pem_password_cb *cb, void *u);
 156  int PEM_write_bio_RSAPublicKey(BIO *bp, RSA *x);
 157  int PEM_write_RSAPublicKey(FILE *fp, RSA *x);
 158
 159  RSA *PEM_read_bio_RSA_PUBKEY(BIO *bp, RSA **x,
 160                               pem_password_cb *cb, void *u);
 161  RSA *PEM_read_RSA_PUBKEY(FILE *fp, RSA **x,
 162                           pem_password_cb *cb, void *u);
 163  int PEM_write_bio_RSA_PUBKEY(BIO *bp, RSA *x);
 164  int PEM_write_RSA_PUBKEY(FILE *fp, RSA *x);
 165
 166  DSA *PEM_read_bio_DSAPrivateKey(BIO *bp, DSA **x,
 167                                  pem_password_cb *cb, void *u);
 168  DSA *PEM_read_DSAPrivateKey(FILE *fp, DSA **x,
 169                              pem_password_cb *cb, void *u);
 170  int PEM_write_bio_DSAPrivateKey(BIO *bp, DSA *x, const EVP_CIPHER *enc,
 171                                  unsigned char *kstr, int klen,
 172                                  pem_password_cb *cb, void *u);
 173  int PEM_write_DSAPrivateKey(FILE *fp, DSA *x, const EVP_CIPHER *enc,
 174                              unsigned char *kstr, int klen,
 175                              pem_password_cb *cb, void *u);
 176
 177  DSA *PEM_read_bio_DSA_PUBKEY(BIO *bp, DSA **x,
 178                               pem_password_cb *cb, void *u);
 179  DSA *PEM_read_DSA_PUBKEY(FILE *fp, DSA **x,
 180                           pem_password_cb *cb, void *u);
 181  int PEM_write_bio_DSA_PUBKEY(BIO *bp, DSA *x);
 182  int PEM_write_DSA_PUBKEY(FILE *fp, DSA *x);
 183  DSA *PEM_read_bio_DSAparams(BIO *bp, DSA **x, pem_password_cb *cb, void *u);
 184  DSA *PEM_read_DSAparams(FILE *fp, DSA **x, pem_password_cb *cb, void *u);
 185  int PEM_write_bio_DSAparams(BIO *bp, DSA *x);
 186  int PEM_write_DSAparams(FILE *fp, DSA *x);
 187
 188  DH *PEM_read_bio_DHparams(BIO *bp, DH **x, pem_password_cb *cb, void *u);
 189  DH *PEM_read_DHparams(FILE *fp, DH **x, pem_password_cb *cb, void *u);
 190  int PEM_write_bio_DHparams(BIO *bp, DH *x);
 191  int PEM_write_DHparams(FILE *fp, DH *x);
 192
 193 =head1 DESCRIPTION
 194
 195 All of the functions described on this page that have a I<TYPE> of B<DH>, B<DSA>
 196 and B<RSA> are deprecated. Applications should use L<OSSL_ENCODER_to_bio(3)> and
 197 L<OSSL_DECODER_from_bio(3)> instead.
 198
 199 The PEM functions read or write structures in PEM format. In
 200 this sense PEM format is simply base64 encoded data surrounded
 201 by header lines.
 202
 203 For more details about the meaning of arguments see the
 204 B<PEM FUNCTION ARGUMENTS> section.
 205
 206 Each operation has four functions associated with it. For
 207 brevity the term "B<I<TYPE>> functions" will be used below to collectively
 208 refer to the B<PEM_read_bio_I<TYPE>>(), B<PEM_read_I<TYPE>>(),
 209 B<PEM_write_bio_I<TYPE>>(), and B<PEM_write_I<TYPE>>() functions.
 210
 211 Some operations have additional variants that take a library context I<libctx>
 212 and a property query string I<propq>. The B<X509>, B<X509_REQ> and B<X509_CRL>
 213 objects may have an associated library context or property query string but
 214 there are no variants of these functions that take a library context or property
 215 query string parameter. In this case it is possible to set the appropriate
 216 library context or property query string by creating an empty B<X509>,
 217 B<X509_REQ> or B<X509_CRL> object using L<X509_new_ex(3)>, L<X509_REQ_new_ex(3)>
 218 or L<X509_CRL_new_ex(3)> respectively. Then pass the empty object as a parameter
 219 to the relevant PEM function. See the L</EXAMPLES> section below.
 220
 221 The B<PrivateKey> functions read or write a private key in PEM format using
 222 an EVP_PKEY structure. The write routines use PKCS#8 private key format and are
 223 equivalent to PEM_write_bio_PKCS8PrivateKey(). The read functions transparently
 224 handle traditional and PKCS#8 format encrypted and unencrypted keys.
 225
 226 PEM_write_bio_PrivateKey_traditional() writes out a private key in the
 227 "traditional" format with a simple private key marker and should only
 228 be used for compatibility with legacy programs.
 229
 230 PEM_write_bio_PKCS8PrivateKey() and PEM_write_PKCS8PrivateKey() write a private
 231 key in an EVP_PKEY structure in PKCS#8 EncryptedPrivateKeyInfo format using
 232 PKCS#5 v2.0 password based encryption algorithms. The I<cipher> argument
 233 specifies the encryption algorithm to use: unlike some other PEM routines the
 234 encryption is applied at the PKCS#8 level and not in the PEM headers. If
 235 I<cipher> is NULL then no encryption is used and a PKCS#8 PrivateKeyInfo
 236 structure is used instead.
 237
 238 PEM_write_bio_PKCS8PrivateKey_nid() and PEM_write_PKCS8PrivateKey_nid()
 239 also write out a private key as a PKCS#8 EncryptedPrivateKeyInfo however
 240 it uses PKCS#5 v1.5 or PKCS#12 encryption algorithms instead. The algorithm
 241 to use is specified in the I<nid> parameter and should be the NID of the
 242 corresponding OBJECT IDENTIFIER (see NOTES section).
 243
 244 The B<PUBKEY> functions process a public key using an EVP_PKEY
 245 structure. The public key is encoded as a SubjectPublicKeyInfo
 246 structure.
 247
 248 The B<RSAPrivateKey> functions process an RSA private key using an
 249 RSA structure. The write routines uses traditional format. The read
 250 routines handles the same formats as the B<PrivateKey>
 251 functions but an error occurs if the private key is not RSA.
 252
 253 The B<RSAPublicKey> functions process an RSA public key using an
 254 RSA structure. The public key is encoded using a PKCS#1 RSAPublicKey
 255 structure.
 256
 257 The B<RSA_PUBKEY> functions also process an RSA public key using
 258 an RSA structure. However, the public key is encoded using a
 259 SubjectPublicKeyInfo structure and an error occurs if the public
 260 key is not RSA.
 261
 262 The B<DSAPrivateKey> functions process a DSA private key using a
 263 DSA structure. The write routines uses traditional format. The read
 264 routines handles the same formats as the B<PrivateKey>
 265 functions but an error occurs if the private key is not DSA.
 266
 267 The B<DSA_PUBKEY> functions process a DSA public key using
 268 a DSA structure. The public key is encoded using a
 269 SubjectPublicKeyInfo structure and an error occurs if the public
 270 key is not DSA.
 271
 272 The B<Parameters> functions read or write key parameters in PEM format using
 273 an EVP_PKEY structure.  The encoding depends on the type of key; for DSA key
 274 parameters, it will be a Dss-Parms structure as defined in RFC2459, and for DH
 275 key parameters, it will be a PKCS#3 DHparameter structure.  I<These functions
 276 only exist for the B<BIO> type>.
 277
 278 The B<DSAparams> functions process DSA parameters using a DSA
 279 structure. The parameters are encoded using a Dss-Parms structure
 280 as defined in RFC2459.
 281
 282 The B<DHparams> functions process DH parameters using a DH
 283 structure. The parameters are encoded using a PKCS#3 DHparameter
 284 structure.
 285
 286 The B<X509> functions process an X509 certificate using an X509
 287 structure. They will also process a trusted X509 certificate but
 288 any trust settings are discarded.
 289
 290 The B<X509_AUX> functions process a trusted X509 certificate using
 291 an X509 structure.
 292
 293 The B<X509_REQ> and B<X509_REQ_NEW> functions process a PKCS#10
 294 certificate request using an X509_REQ structure. The B<X509_REQ>
 295 write functions use B<CERTIFICATE REQUEST> in the header whereas
 296 the B<X509_REQ_NEW> functions use B<NEW CERTIFICATE REQUEST>
 297 (as required by some CAs). The B<X509_REQ> read functions will
 298 handle either form so there are no B<X509_REQ_NEW> read functions.
 299
 300 The B<X509_CRL> functions process an X509 CRL using an X509_CRL
 301 structure.
 302
 303 The B<PKCS7> functions process a PKCS#7 ContentInfo using a PKCS7
 304 structure.
 305
 306 =head1 PEM FUNCTION ARGUMENTS
 307
 308 The PEM functions have many common arguments.
 309
 310 The I<bp> BIO parameter (if present) specifies the BIO to read from
 311 or write to.
 312
 313 The I<fp> FILE parameter (if present) specifies the FILE pointer to
 314 read from or write to.
 315
 316 The PEM read functions all take an argument I<B<TYPE> **x> and return
 317 a I<B<TYPE> *> pointer. Where I<B<TYPE>> is whatever structure the function
 318 uses. If I<x> is NULL then the parameter is ignored. If I<x> is not
 319 NULL but I<*x> is NULL then the structure returned will be written
 320 to I<*x>. If neither I<x> nor I<*x> is NULL then an attempt is made
 321 to reuse the structure at I<*x> (but see BUGS and EXAMPLES sections).
 322 Irrespective of the value of I<x> a pointer to the structure is always
 323 returned (or NULL if an error occurred).
 324
 325 The PEM functions which write private keys take an I<enc> parameter
 326 which specifies the encryption algorithm to use, encryption is done
 327 at the PEM level. If this parameter is set to NULL then the private
 328 key is written in unencrypted form.
 329
 330 The I<cb> argument is the callback to use when querying for the pass
 331 phrase used for encrypted PEM structures (normally only private keys).
 332
 333 For the PEM write routines if the I<kstr> parameter is not NULL then
 334 I<klen> bytes at I<kstr> are used as the passphrase and I<cb> is
 335 ignored.
 336
 337 If the I<cb> parameters is set to NULL and the I<u> parameter is not
 338 NULL then the I<u> parameter is interpreted as a NUL terminated string
 339 to use as the passphrase. If both I<cb> and I<u> are NULL then the
 340 default callback routine is used which will typically prompt for the
 341 passphrase on the current terminal with echoing turned off.
 342
 343 The default passphrase callback is sometimes inappropriate (for example
 344 in a GUI application) so an alternative can be supplied. The callback
 345 routine has the following form:
 346
 347  int cb(char *buf, int size, int rwflag, void *u);
 348
 349 I<buf> is the buffer to write the passphrase to. I<size> is the maximum
 350 length of the passphrase (i.e. the size of buf). I<rwflag> is a flag
 351 which is set to 0 when reading and 1 when writing. A typical routine
 352 will ask the user to verify the passphrase (for example by prompting
 353 for it twice) if I<rwflag> is 1. The I<u> parameter has the same
 354 value as the I<u> parameter passed to the PEM routine. It allows
 355 arbitrary data to be passed to the callback by the application
 356 (for example a window handle in a GUI application). The callback
 357 I<must> return the number of characters in the passphrase or -1 if
 358 an error occurred. The passphrase can be arbitrary data; in the case where it
 359 is a string, it is not NUL terminated. See the L</EXAMPLES> section below.
 360
 361 Some implementations may need to use cryptographic algorithms during their
 362 operation. If this is the case and I<libctx> and I<propq> parameters have been
 363 passed then any algorithm fetches will use that library context and property
 364 query string. Otherwise the default library context and property query string
 365 will be used.
 366
 367 =head1 NOTES
 368
 369 The PEM reading functions will skip any extraneous content or PEM data of
 370 a different type than they expect. This allows for example having a certificate
 371 (or multiple certificates) and a key in the PEM format in a single file.
 372
 373 The old B<PrivateKey> write routines are retained for compatibility.
 374 New applications should write private keys using the
 375 PEM_write_bio_PKCS8PrivateKey() or PEM_write_PKCS8PrivateKey() routines
 376 because they are more secure (they use an iteration count of 2048 whereas
 377 the traditional routines use a count of 1) unless compatibility with older
 378 versions of OpenSSL is important.
 379
 380 The B<PrivateKey> read routines can be used in all applications because
 381 they handle all formats transparently.
 382
 383 A frequent cause of problems is attempting to use the PEM routines like
 384 this:
 385
 386  X509 *x;
 387
 388  PEM_read_bio_X509(bp, &x, 0, NULL);
 389
 390 this is a bug because an attempt will be made to reuse the data at I<x>
 391 which is an uninitialised pointer.
 392
 393 These functions make no assumption regarding the pass phrase received from the
 394 password callback.
 395 It will simply be treated as a byte sequence.
 396
 397 =head1 PEM ENCRYPTION FORMAT
 398
 399 These old B<PrivateKey> routines use a non standard technique for encryption.
 400
 401 The private key (or other data) takes the following form:
 402
 403  -----BEGIN RSA PRIVATE KEY-----
 404  Proc-Type: 4,ENCRYPTED
 405  DEK-Info: DES-EDE3-CBC,3F17F5316E2BAC89
 406
 407  ...base64 encoded data...
 408  -----END RSA PRIVATE KEY-----
 409
 410 The line beginning with I<Proc-Type> contains the version and the
 411 protection on the encapsulated data. The line beginning I<DEK-Info>
 412 contains two comma separated values: the encryption algorithm name as
 413 used by EVP_get_cipherbyname() and an initialization vector used by the
 414 cipher encoded as a set of hexadecimal digits. After those two lines is
 415 the base64-encoded encrypted data.
 416
 417 The encryption key is derived using EVP_BytesToKey(). The cipher's
 418 initialization vector is passed to EVP_BytesToKey() as the I<salt>
 419 parameter. Internally, B<PKCS5_SALT_LEN> bytes of the salt are used
 420 (regardless of the size of the initialization vector). The user's
 421 password is passed to EVP_BytesToKey() using the I<data> and I<datal>
 422 parameters. Finally, the library uses an iteration count of 1 for
 423 EVP_BytesToKey().
 424
 425 The I<key> derived by EVP_BytesToKey() along with the original initialization
 426 vector is then used to decrypt the encrypted data. The I<iv> produced by
 427 EVP_BytesToKey() is not utilized or needed, and NULL should be passed to
 428 the function.
 429
 430 The pseudo code to derive the key would look similar to:
 431
 432  EVP_CIPHER* cipher = EVP_des_ede3_cbc();
 433  EVP_MD* md = EVP_md5();
 434
 435  unsigned int nkey = EVP_CIPHER_get_key_length(cipher);
 436  unsigned int niv = EVP_CIPHER_get_iv_length(cipher);
 437  unsigned char key[nkey];
 438  unsigned char iv[niv];
 439
 440  memcpy(iv, HexToBin("3F17F5316E2BAC89"), niv);
 441  rc = EVP_BytesToKey(cipher, md, iv /*salt*/, pword, plen, 1, key, NULL /*iv*/);
 442  if (rc != nkey)
 443      /* Error */
 444
 445  /* On success, use key and iv to initialize the cipher */
 446
 447 =head1 BUGS
 448
 449 The PEM read routines in some versions of OpenSSL will not correctly reuse
 450 an existing structure. Therefore, the following:
 451
 452  PEM_read_bio_X509(bp, &x, 0, NULL);
 453
 454 where I<x> already contains a valid certificate, may not work, whereas:
 455
 456  X509_free(x);
 457  x = PEM_read_bio_X509(bp, NULL, 0, NULL);
 458
 459 is guaranteed to work. It is always acceptable for I<x> to contain a newly
 460 allocated, empty B<X509> object (for example allocated via L<X509_new_ex(3)>).
 461
 462 =head1 RETURN VALUES
 463
 464 The read routines return either a pointer to the structure read or NULL
 465 if an error occurred.
 466
 467 The write routines return 1 for success or 0 for failure.
 468
 469 =head1 EXAMPLES
 470
 471 Although the PEM routines take several arguments in almost all applications
 472 most of them are set to 0 or NULL.
 473
 474 To read a certificate with a library context in PEM format from a BIO:
 475
 476  X509 *x = X509_new_ex(libctx, NULL);
 477
 478  if (x == NULL)
 479      /* Error */
 480
 481  if (PEM_read_bio_X509(bp, &x, 0, NULL) == NULL)
 482      /* Error */
 483
 484 Read a certificate in PEM format from a BIO:
 485
 486  X509 *x;
 487
 488  x = PEM_read_bio_X509(bp, NULL, 0, NULL);
 489  if (x == NULL)
 490      /* Error */
 491
 492 Alternative method:
 493
 494  X509 *x = NULL;
 495
 496  if (!PEM_read_bio_X509(bp, &x, 0, NULL))
 497      /* Error */
 498
 499 Write a certificate to a BIO:
 500
 501  if (!PEM_write_bio_X509(bp, x))
 502      /* Error */
 503
 504 Write a private key (using traditional format) to a BIO using
 505 triple DES encryption, the pass phrase is prompted for:
 506
 507  if (!PEM_write_bio_PrivateKey(bp, key, EVP_des_ede3_cbc(), NULL, 0, 0, NULL))
 508      /* Error */
 509
 510 Write a private key (using PKCS#8 format) to a BIO using triple
 511 DES encryption, using the pass phrase "hello":
 512
 513  if (!PEM_write_bio_PKCS8PrivateKey(bp, key, EVP_des_ede3_cbc(),
 514                                     NULL, 0, 0, "hello"))
 515      /* Error */
 516
 517 Read a private key from a BIO using a pass phrase callback:
 518
 519  key = PEM_read_bio_PrivateKey(bp, NULL, pass_cb, "My Private Key");
 520  if (key == NULL)
 521      /* Error */
 522
 523 Skeleton pass phrase callback:
 524
 525  int pass_cb(char *buf, int size, int rwflag, void *u)
 526  {
 527
 528      /* We'd probably do something else if 'rwflag' is 1 */
 529      printf("Enter pass phrase for \"%s\"\n", (char *)u);
 530
 531      /* get pass phrase, length 'len' into 'tmp' */
 532      char *tmp = "hello";
 533      if (tmp == NULL) /* An error occurred */
 534          return -1;
 535
 536      size_t len = strlen(tmp);
 537
 538      if (len > size)
 539          len = size;
 540      memcpy(buf, tmp, len);
 541      return len;
 542  }
 543
 544 =head1 SEE ALSO
 545
 546 L<EVP_EncryptInit(3)>, L<EVP_BytesToKey(3)>,
 547 L<passphrase-encoding(7)>
 548
 549 =head1 HISTORY
 550
 551 The old Netscape certificate sequences were no longer documented
 552 in OpenSSL 1.1.0; applications should use the PKCS7 standard instead
 553 as they will be formally deprecated in a future releases.
 554
 555 PEM_read_bio_PrivateKey_ex(), PEM_read_PrivateKey_ex(),
 556 PEM_read_bio_PUBKEY_ex(), PEM_read_PUBKEY_ex() and
 557 PEM_read_bio_Parameters_ex() were introduced in OpenSSL 3.0.
 558
 559 The functions PEM_read_bio_RSAPrivateKey(), PEM_read_RSAPrivateKey(),
 560 PEM_write_bio_RSAPrivateKey(), PEM_write_RSAPrivateKey(),
 561 PEM_read_bio_RSAPublicKey(), PEM_read_RSAPublicKey(),
 562 PEM_write_bio_RSAPublicKey(), PEM_write_RSAPublicKey(),
 563 PEM_read_bio_RSA_PUBKEY(), PEM_read_RSA_PUBKEY(),
 564 PEM_write_bio_RSA_PUBKEY(), PEM_write_RSA_PUBKEY(),
 565 PEM_read_bio_DSAPrivateKey(), PEM_read_DSAPrivateKey(),
 566 PEM_write_bio_DSAPrivateKey(), PEM_write_DSAPrivateKey(),
 567 PEM_read_bio_DSA_PUBKEY(), PEM_read_DSA_PUBKEY(),
 568 PEM_write_bio_DSA_PUBKEY(), PEM_write_DSA_PUBKEY();
 569 PEM_read_bio_DSAparams(), PEM_read_DSAparams(),
 570 PEM_write_bio_DSAparams(), PEM_write_DSAparams(),
 571 PEM_read_bio_DHparams(), PEM_read_DHparams(),
 572 PEM_write_bio_DHparams() and PEM_write_DHparams() were deprecated in 3.0.
 573
 574
 575 =head1 COPYRIGHT
 576
 577 Copyright 2001-2022 The OpenSSL Project Authors. All Rights Reserved.
 578
 579 Licensed under the Apache License 2.0 (the "License").  You may not use
 580 this file except in compliance with the License.  You can obtain a copy
 581 in the file LICENSE in the source distribution or at
 582 L<https://www.openssl.org/source/license.html>.
 583
 584 =cut