doc/man1/openssl-genpkey.pod.in

   1 =pod
   2
   3 =begin comment
   4 {- join("\n", @autowarntext) -}
   5
   6 =end comment
   7
   8 =head1 NAME
   9
  10 openssl-genpkey - generate a private key
  11
  12 =head1 SYNOPSIS
  13
  14 B<openssl> B<genpkey>
  15 [B<-help>]
  16 [B<-out> I<filename>]
  17 [B<-outform> B<DER>|B<PEM>]
  18 [B<-pass> I<arg>]
  19 [B<-I<cipher>>]
  20 [B<-paramfile> I<file>]
  21 [B<-algorithm> I<alg>]
  22 [B<-pkeyopt> I<opt>:I<value>]
  23 [B<-genparam>]
  24 [B<-text>]
  25 {- $OpenSSL::safe::opt_engine_synopsis -}{- $OpenSSL::safe::opt_provider_synopsis -}
  26 {- $OpenSSL::safe::opt_config_synopsis -}
  27
  28 =for openssl ifdef engine
  29
  30 =head1 DESCRIPTION
  31
  32 This command generates a private key.
  33
  34 =head1 OPTIONS
  35
  36 =over 4
  37
  38 =item B<-help>
  39
  40 Print out a usage message.
  41
  42 =item B<-out> I<filename>
  43
  44 Output the key to the specified file. If this argument is not specified then
  45 standard output is used.
  46
  47 =item B<-outform> B<DER>|B<PEM>
  48
  49 The output format, except when B<-genparam> is given; the default is B<PEM>.
  50 See L<openssl-format-options(1)> for details.
  51
  52 When B<-genparam> is given, B<-outform> is ignored.
  53
  54 =item B<-pass> I<arg>
  55
  56 The output file password source. For more information about the format of I<arg>
  57 see L<openssl-passphrase-options(1)>.
  58
  59 =item B<-I<cipher>>
  60
  61 This option encrypts the private key with the supplied cipher. Any algorithm
  62 name accepted by EVP_get_cipherbyname() is acceptable such as B<des3>.
  63
  64 =item B<-algorithm> I<alg>
  65
  66 Public key algorithm to use such as RSA, DSA or DH. If used this option must
  67 precede any B<-pkeyopt> options. The options B<-paramfile> and B<-algorithm>
  68 are mutually exclusive. Engines may add algorithms in addition to the standard
  69 built-in ones.
  70
  71 Valid built-in algorithm names for private key generation are RSA, RSA-PSS, EC,
  72 X25519, X448, ED25519 and ED448.
  73
  74 Valid built-in algorithm names for parameter generation (see the B<-genparam>
  75 option) are DH, DSA and EC.
  76
  77 Note that the algorithm name X9.42 DH may be used as a synonym for the DH
  78 algorithm. These are identical and do not indicate the type of parameters that
  79 will be generated. Use the B<dh_paramgen_type> option to indicate whether PKCS#3
  80 or X9.42 DH parameters are required. See L</DH Parameter Generation Options>
  81 below for more details.
  82
  83 =item B<-pkeyopt> I<opt>:I<value>
  84
  85 Set the public key algorithm option I<opt> to I<value>. The precise set of
  86 options supported depends on the public key algorithm used and its
  87 implementation. See L</KEY GENERATION OPTIONS> and
  88 L</PARAMETER GENERATION OPTIONS> below for more details.
  89
  90 =item B<-genparam>
  91
  92 Generate a set of parameters instead of a private key. If used this option must
  93 precede any B<-algorithm>, B<-paramfile> or B<-pkeyopt> options.
  94
  95 =item B<-paramfile> I<filename>
  96
  97 Some public key algorithms generate a private key based on a set of parameters.
  98 They can be supplied using this option. If this option is used the public key
  99 algorithm used is determined by the parameters. If used this option must
 100 precede any B<-pkeyopt> options. The options B<-paramfile> and B<-algorithm>
 101 are mutually exclusive.
 102
 103 =item B<-text>
 104
 105 Print an (unencrypted) text representation of private and public keys and
 106 parameters along with the PEM or DER structure.
 107
 108 {- $OpenSSL::safe::opt_engine_item -}
 109
 110 {- $OpenSSL::safe::opt_provider_item -}
 111
 112 {- $OpenSSL::safe::opt_config_item -}
 113
 114 =back
 115
 116 =head1 KEY GENERATION OPTIONS
 117
 118 The options supported by each algorithm and indeed each implementation of an
 119 algorithm can vary. The options for the OpenSSL implementations are detailed
 120 below. There are no key generation options defined for the X25519, X448, ED25519
 121 or ED448 algorithms.
 122
 123 =head2 RSA Key Generation Options
 124
 125 =over 4
 126
 127 =item B<rsa_keygen_bits:numbits>
 128
 129 The number of bits in the generated key. If not specified 2048 is used.
 130
 131 =item B<rsa_keygen_primes:numprimes>
 132
 133 The number of primes in the generated key. If not specified 2 is used.
 134
 135 =item B<rsa_keygen_pubexp:value>
 136
 137 The RSA public exponent value. This can be a large decimal or
 138 hexadecimal value if preceded by C<0x>. Default value is 65537.
 139
 140 =back
 141
 142 =head2 RSA-PSS Key Generation Options
 143
 144 Note: by default an B<RSA-PSS> key has no parameter restrictions.
 145
 146 =over 4
 147
 148 =item B<rsa_keygen_bits>:I<numbits>, B<rsa_keygen_primes>:I<numprimes>,
 149 B<rsa_keygen_pubexp>:I<value>
 150
 151 These options have the same meaning as the B<RSA> algorithm.
 152
 153 =item B<rsa_pss_keygen_md>:I<digest>
 154
 155 If set the key is restricted and can only use I<digest> for signing.
 156
 157 =item B<rsa_pss_keygen_mgf1_md>:I<digest>
 158
 159 If set the key is restricted and can only use I<digest> as it's MGF1
 160 parameter.
 161
 162 =item B<rsa_pss_keygen_saltlen>:I<len>
 163
 164 If set the key is restricted and I<len> specifies the minimum salt length.
 165
 166 =back
 167
 168 =head2 EC Key Generation Options
 169
 170 The EC key generation options can also be used for parameter generation.
 171
 172 =over 4
 173
 174 =item B<ec_paramgen_curve>:I<curve>
 175
 176 The EC curve to use. OpenSSL supports NIST curve names such as "P-256".
 177
 178 =item B<ec_param_enc>:I<encoding>
 179
 180 The encoding to use for parameters. The I<encoding> parameter must be either
 181 B<named_curve> or B<explicit>. The default value is B<named_curve>.
 182
 183 =back
 184
 185 =head1 PARAMETER GENERATION OPTIONS
 186
 187 The options supported by each algorithm and indeed each implementation of an
 188 algorithm can vary. The options for the OpenSSL implementations are detailed
 189 below.
 190
 191 =head2 DSA Parameter Generation Options
 192
 193 =over 4
 194
 195 =item B<dsa_paramgen_bits>:I<numbits>
 196
 197 The number of bits in the generated prime. If not specified 2048 is used.
 198
 199 =item B<dsa_paramgen_q_bits>:I<numbits>
 200
 201 =item B<qbits>:I<numbits>
 202
 203 The number of bits in the q parameter. Must be one of 160, 224 or 256. If not
 204 specified 224 is used.
 205
 206 =item B<dsa_paramgen_md>:I<digest>
 207
 208 =item B<digest>:I<digest>
 209
 210 The digest to use during parameter generation. Must be one of B<sha1>, B<sha224>
 211 or B<sha256>. If set, then the number of bits in B<q> will match the output size
 212 of the specified digest and the B<dsa_paramgen_q_bits> parameter will be
 213 ignored. If not set, then a digest will be used that gives an output matching
 214 the number of bits in B<q>, i.e. B<sha1> if q length is 160, B<sha224> if it 224
 215 or B<sha256> if it is 256.
 216
 217
 218 =item B<properties>:I<query>
 219
 220 The I<digest> property I<query> string to use when fetching a digest from a provider.
 221
 222 =item B<type>:I<type>
 223
 224 The type of generation to use. Set this to 1 to use legacy FIPS186-2 parameter
 225 generation. The default of 0 uses FIPS186-4 parameter generation.
 226
 227 =item B<gindex>:I<index>
 228
 229 The index to use for canonical generation and verification of the generator g.
 230 Set this to a positive value ranging from 0..255 to use this mode. Larger values
 231 will only use the bottom byte.
 232 This I<index> must then be reused during key validation to verify the value of g.
 233 If this value is not set then g is not verifiable. The default value is -1.
 234
 235 =item B<hexseed>:I<seed>
 236
 237 The seed I<seed> data to use instead of generating a random seed internally.
 238 This should be used for testing purposes only. This will either produced fixed
 239 values for the generated parameters OR it will fail if the seed did not
 240 generate valid primes.
 241
 242 =back
 243
 244 =head2 DH Parameter Generation Options
 245
 246 =over 4
 247
 248 =item B<dh_paramgen_prime_len>:I<numbits>
 249
 250 The number of bits in the prime parameter I<p>. The default is 2048.
 251
 252 =item B<dh_paramgen_subprime_len>:I<numbits>
 253
 254 The number of bits in the sub prime parameter I<q>. The default is 256 if the
 255 prime is at least 2048 bits long or 160 otherwise. Only relevant if used in
 256 conjunction with the B<dh_paramgen_type> option to generate X9.42 DH parameters.
 257
 258 =item B<dh_paramgen_generator>:I<value>
 259
 260 The value to use for the generator I<g>. The default is 2.
 261
 262 =item B<dh_paramgen_type>:I<value>
 263
 264 The type of DH parameters to generate. Use 0 for PKCS#3 DH and 1 for X9.42 DH.
 265 The default is 0.
 266
 267 =item B<dh_rfc5114>:I<num>
 268
 269 If this option is set, then the appropriate RFC5114 parameters are used
 270 instead of generating new parameters. The value I<num> can be one of
 271 1, 2 or 3 corresponding to RFC5114 DH parameters consisting of
 272 1024 bit group with 160 bit subgroup, 2048 bit group with 224 bit subgroup
 273 and 2048 bit group with 256 bit subgroup as mentioned in RFC5114 sections
 274 2.1, 2.2 and 2.3 respectively. If present this overrides all other DH parameter
 275 options.
 276
 277 =back
 278
 279 =head2 EC Parameter Generation Options
 280
 281 The EC parameter generation options are the same as for key generation. See
 282 L</EC Key Generation Options> above.
 283
 284 =head1 NOTES
 285
 286 The use of the genpkey program is encouraged over the algorithm specific
 287 utilities because additional algorithm options and ENGINE provided algorithms
 288 can be used.
 289
 290 =head1 EXAMPLES
 291
 292 Generate an RSA private key using default parameters:
 293
 294  openssl genpkey -algorithm RSA -out key.pem
 295
 296 Encrypt output private key using 128 bit AES and the passphrase "hello":
 297
 298  openssl genpkey -algorithm RSA -out key.pem -aes-128-cbc -pass pass:hello
 299
 300 Generate a 2048 bit RSA key using 3 as the public exponent:
 301
 302  openssl genpkey -algorithm RSA -out key.pem \
 303      -pkeyopt rsa_keygen_bits:2048 -pkeyopt rsa_keygen_pubexp:3
 304
 305 Generate 2048 bit DSA parameters that can be validated: The output values for
 306 gindex and seed are required for key validation purposes and are not saved to
 307 the output pem file).
 308
 309  openssl genpkey -genparam -algorithm DSA -out dsap.pem -pkeyopt pbits:2048 \
 310      -pkeyopt qbits:224 -pkeyopt digest:SHA256 -pkeyopt gindex:1 -text
 311
 312 Generate DSA key from parameters:
 313
 314  openssl genpkey -paramfile dsap.pem -out dsakey.pem
 315
 316 Generate 2048 bit DH parameters:
 317
 318  openssl genpkey -genparam -algorithm DH -out dhp.pem \
 319      -pkeyopt dh_paramgen_prime_len:2048
 320
 321 Generate 2048 bit X9.42 DH parameters:
 322
 323  openssl genpkey -genparam -algorithm DH -out dhpx.pem \
 324      -pkeyopt dh_paramgen_prime_len:2048 \
 325      -pkeyopt dh_paramgen_type:1
 326
 327 Output RFC5114 2048 bit DH parameters with 224 bit subgroup:
 328
 329  openssl genpkey -genparam -algorithm DH -out dhp.pem -pkeyopt dh_rfc5114:2
 330
 331 Generate DH key from parameters:
 332
 333  openssl genpkey -paramfile dhp.pem -out dhkey.pem
 334
 335 Generate EC parameters:
 336
 337  openssl genpkey -genparam -algorithm EC -out ecp.pem \
 338         -pkeyopt ec_paramgen_curve:secp384r1 \
 339         -pkeyopt ec_param_enc:named_curve
 340
 341 Generate EC key from parameters:
 342
 343  openssl genpkey -paramfile ecp.pem -out eckey.pem
 344
 345 Generate EC key directly:
 346
 347  openssl genpkey -algorithm EC -out eckey.pem \
 348         -pkeyopt ec_paramgen_curve:P-384 \
 349         -pkeyopt ec_param_enc:named_curve
 350
 351 Generate an X25519 private key:
 352
 353  openssl genpkey -algorithm X25519 -out xkey.pem
 354
 355 Generate an ED448 private key:
 356
 357  openssl genpkey -algorithm ED448 -out xkey.pem
 358
 359 =head1 HISTORY
 360
 361 The ability to use NIST curve names, and to generate an EC key directly,
 362 were added in OpenSSL 1.0.2.
 363 The ability to generate X25519 keys was added in OpenSSL 1.1.0.
 364 The ability to generate X448, ED25519 and ED448 keys was added in OpenSSL 1.1.1.
 365
 366 The B<-engine> option was deprecated in OpenSSL 3.0.
 367
 368 =head1 COPYRIGHT
 369
 370 Copyright 2006-2020 The OpenSSL Project Authors. All Rights Reserved.
 371
 372 Licensed under the Apache License 2.0 (the "License").  You may not use
 373 this file except in compliance with the License.  You can obtain a copy
 374 in the file LICENSE in the source distribution or at
 375 L<https://www.openssl.org/source/license.html>.
 376
 377 =cut