1=pod 2 3=head1 NAME 4 5genpkey - generate a private key 6 7=head1 SYNOPSIS 8 9B<openssl> B<genpkey> 10[B<-out filename>] 11[B<-outform PEM|DER>] 12[B<-pass arg>] 13[B<-cipher>] 14[B<-engine id>] 15[B<-paramfile file>] 16[B<-algorithm alg>] 17[B<-pkeyopt opt:value>] 18[B<-genparam>] 19[B<-text>] 20 21=head1 DESCRIPTION 22 23The B<genpkey> command generates a private key. 24 25=head1 OPTIONS 26 27=over 4 28 29=item B<-out filename> 30 31the output filename. If this argument is not specified then standard output is 32used. 33 34=item B<-outform DER|PEM> 35 36This specifies the output format DER or PEM. 37 38=item B<-pass arg> 39 40the output file password source. For more information about the format of B<arg> 41see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>. 42 43=item B<-cipher> 44 45This option encrypts the private key with the supplied cipher. Any algorithm 46name accepted by EVP_get_cipherbyname() is acceptable such as B<des3>. 47 48=item B<-engine id> 49 50specifying an engine (by its unique B<id> string) will cause B<genpkey> 51to attempt to obtain a functional reference to the specified engine, 52thus initialising it if needed. The engine will then be set as the default 53for all available algorithms. If used this option should precede all other 54options. 55 56=item B<-algorithm alg> 57 58public key algorithm to use such as RSA, DSA or DH. If used this option must 59precede any B<-pkeyopt> options. The options B<-paramfile> and B<-algorithm> 60are mutually exclusive. 61 62=item B<-pkeyopt opt:value> 63 64set the public key algorithm option B<opt> to B<value>. The precise set of 65options supported depends on the public key algorithm used and its 66implementation. See B<KEY GENERATION OPTIONS> below for more details. 67 68=item B<-genparam> 69 70generate a set of parameters instead of a private key. If used this option must 71precede and B<-algorithm>, B<-paramfile> or B<-pkeyopt> options. 72 73=item B<-paramfile filename> 74 75Some public key algorithms generate a private key based on a set of parameters. 76They can be supplied using this option. If this option is used the public key 77algorithm used is determined by the parameters. If used this option must 78precede and B<-pkeyopt> options. The options B<-paramfile> and B<-algorithm> 79are mutually exclusive. 80 81=item B<-text> 82 83Print an (unencrypted) text representation of private and public keys and 84parameters along with the PEM or DER structure. 85 86=back 87 88=head1 KEY GENERATION OPTIONS 89 90The options supported by each algorith and indeed each implementation of an 91algorithm can vary. The options for the OpenSSL implementations are detailed 92below. 93 94=head1 RSA KEY GENERATION OPTIONS 95 96=over 4 97 98=item B<rsa_keygen_bits:numbits> 99 100The number of bits in the generated key. If not specified 1024 is used. 101 102=item B<rsa_keygen_pubexp:value> 103 104The RSA public exponent value. This can be a large decimal or 105hexadecimal value if preceded by B<0x>. Default value is 65537. 106 107=back 108 109=head1 DSA PARAMETER GENERATION OPTIONS 110 111=over 4 112 113=item B<dsa_paramgen_bits:numbits> 114 115The number of bits in the generated parameters. If not specified 1024 is used. 116 117=back 118 119=head1 DH PARAMETER GENERATION OPTIONS 120 121=over 4 122 123=item B<dh_paramgen_prime_len:numbits> 124 125The number of bits in the prime parameter B<p>. 126 127=item B<dh_paramgen_generator:value> 128 129The value to use for the generator B<g>. 130 131=item B<dh_rfc5114:num> 132 133If this option is set then the appropriate RFC5114 parameters are used 134instead of generating new parameters. The value B<num> can take the 135values 1, 2 or 3 corresponding to RFC5114 DH parameters consisting of 1361024 bit group with 160 bit subgroup, 2048 bit group with 224 bit subgroup 137and 2048 bit group with 256 bit subgroup as mentioned in RFC5114 sections 1382.1, 2.2 and 2.3 respectively. 139 140=back 141 142=head1 EC PARAMETER GENERATION OPTIONS 143 144=over 4 145 146=item B<ec_paramgen_curve:curve> 147 148the EC curve to use. 149 150=back 151 152=head1 GOST2001 KEY GENERATION AND PARAMETER OPTIONS 153 154Gost 2001 support is not enabled by default. To enable this algorithm, 155one should load the ccgost engine in the OpenSSL configuration file. 156See README.gost file in the engines/ccgost directiry of the source 157distribution for more details. 158 159Use of a parameter file for the GOST R 34.10 algorithm is optional. 160Parameters can be specified during key generation directly as well as 161during generation of parameter file. 162 163=over 4 164 165=item B<paramset:name> 166 167Specifies GOST R 34.10-2001 parameter set according to RFC 4357. 168Parameter set can be specified using abbreviated name, object short name or 169numeric OID. Following parameter sets are supported: 170 171 paramset OID Usage 172 A 1.2.643.2.2.35.1 Signature 173 B 1.2.643.2.2.35.2 Signature 174 C 1.2.643.2.2.35.3 Signature 175 XA 1.2.643.2.2.36.0 Key exchange 176 XB 1.2.643.2.2.36.1 Key exchange 177 test 1.2.643.2.2.35.0 Test purposes 178 179=back 180 181 182 183=head1 NOTES 184 185The use of the genpkey program is encouraged over the algorithm specific 186utilities because additional algorithm options and ENGINE provided algorithms 187can be used. 188 189=head1 EXAMPLES 190 191Generate an RSA private key using default parameters: 192 193 openssl genpkey -algorithm RSA -out key.pem 194 195Encrypt output private key using 128 bit AES and the passphrase "hello": 196 197 openssl genpkey -algorithm RSA -out key.pem -aes-128-cbc -pass pass:hello 198 199Generate a 2048 bit RSA key using 3 as the public exponent: 200 201 openssl genpkey -algorithm RSA -out key.pem -pkeyopt rsa_keygen_bits:2048 \ 202 -pkeyopt rsa_keygen_pubexp:3 203 204Generate 1024 bit DSA parameters: 205 206 openssl genpkey -genparam -algorithm DSA -out dsap.pem \ 207 -pkeyopt dsa_paramgen_bits:1024 208 209Generate DSA key from parameters: 210 211 openssl genpkey -paramfile dsap.pem -out dsakey.pem 212 213Generate 1024 bit DH parameters: 214 215 openssl genpkey -genparam -algorithm DH -out dhp.pem \ 216 -pkeyopt dh_paramgen_prime_len:1024 217 218Output RFC5114 2048 bit DH parameters with 224 bit subgroup: 219 220 openssl genpkey -genparam -algorithm DH -out dhp.pem -pkeyopt dh_rfc5114:2 221 222Generate DH key from parameters: 223 224 openssl genpkey -paramfile dhp.pem -out dhkey.pem 225 226 227=cut 228 229