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48.\"
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50.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
51.\" entries marked with X<> in POD. Of course, you'll have to process the
52.\" output yourself in some meaningful fashion.
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129.\" ========================================================================
130.\"
131.IX Title "GENPKEY 1"
132.TH GENPKEY 1 "2018-08-14" "1.0.2p" "OpenSSL"
133.\" For nroff, turn off justification. Always turn off hyphenation; it makes
134.\" way too many mistakes in technical documents.
135.if n .ad l
136.nh
137.SH "NAME"
138openssl\-genpkey,
139genpkey \- generate a private key
140.SH "SYNOPSIS"
141.IX Header "SYNOPSIS"
142\&\fBopenssl\fR \fBgenpkey\fR
143[\fB\-out filename\fR]
144[\fB\-outform PEM|DER\fR]
145[\fB\-pass arg\fR]
146[\fB\-\f(BIcipher\fB\fR]
147[\fB\-engine id\fR]
148[\fB\-paramfile file\fR]
149[\fB\-algorithm alg\fR]
150[\fB\-pkeyopt opt:value\fR]
151[\fB\-genparam\fR]
152[\fB\-text\fR]
153.SH "DESCRIPTION"
154.IX Header "DESCRIPTION"
155The \fBgenpkey\fR command generates a private key.
156.SH "OPTIONS"
157.IX Header "OPTIONS"
158.IP "\fB\-out filename\fR" 4
159.IX Item "-out filename"
160the output filename. If this argument is not specified then standard output is
161used.
162.IP "\fB\-outform DER|PEM\fR" 4
163.IX Item "-outform DER|PEM"
164This specifies the output format \s-1DER\s0 or \s-1PEM.\s0 The default format is \s-1PEM.\s0
165.IP "\fB\-pass arg\fR" 4
166.IX Item "-pass arg"
167The output file password source. For more information about the format of \fBarg\fR
168see the \fB\s-1PASS PHRASE ARGUMENTS\s0\fR section in \fIopenssl\fR\|(1).
169.IP "\fB\-\f(BIcipher\fB\fR" 4
170.IX Item "-cipher"
171This option encrypts the private key with the supplied cipher. Any algorithm
172name accepted by \fIEVP_get_cipherbyname()\fR is acceptable such as \fBdes3\fR.
173.IP "\fB\-engine id\fR" 4
174.IX Item "-engine id"
175Specifying an engine (by its unique \fBid\fR string) will cause \fBgenpkey\fR
176to attempt to obtain a functional reference to the specified engine,
177thus initialising it if needed. The engine will then be set as the default
178for all available algorithms. If used this option should precede all other
179options.
180.IP "\fB\-algorithm alg\fR" 4
181.IX Item "-algorithm alg"
182Public key algorithm to use such as \s-1RSA, DSA\s0 or \s-1DH.\s0 If used this option must
183precede any \fB\-pkeyopt\fR options. The options \fB\-paramfile\fR and \fB\-algorithm\fR
184are mutually exclusive. Engines may add algorithms in addition to the standard
185built-in ones.
186.Sp
187Valid built-in algorithm names for private key generation are \s-1RSA\s0 and \s-1EC.\s0
188.Sp
189Valid built-in algorithm names for parameter generation (see the \fB\-genparam\fR
190option) are \s-1DH, DSA\s0 and \s-1EC.\s0
191.Sp
192Note that the algorithm name X9.42 \s-1DH\s0 may be used as a synonym for the \s-1DH\s0
193algorithm. These are identical and do not indicate the type of parameters that
194will be generated. Use the \fBdh_paramgen_type\fR option to indicate whether PKCS#3
195or X9.42 \s-1DH\s0 parameters are required. See \*(L"\s-1DH\s0 Parameter Generation Options\*(R"
196below for more details.
197.IP "\fB\-pkeyopt opt:value\fR" 4
198.IX Item "-pkeyopt opt:value"
199Set the public key algorithm option \fBopt\fR to \fBvalue\fR. The precise set of
200options supported depends on the public key algorithm used and its
201implementation. See \*(L"\s-1KEY GENERATION OPTIONS\*(R"\s0 and
202\&\*(L"\s-1PARAMETER GENERATION OPTIONS\*(R"\s0 below for more details.
203.IP "\fB\-genparam\fR" 4
204.IX Item "-genparam"
205Generate a set of parameters instead of a private key. If used this option must
206precede any \fB\-algorithm\fR, \fB\-paramfile\fR or \fB\-pkeyopt\fR options.
207.IP "\fB\-paramfile filename\fR" 4
208.IX Item "-paramfile filename"
209Some public key algorithms generate a private key based on a set of parameters.
210They can be supplied using this option. If this option is used the public key
211algorithm used is determined by the parameters. If used this option must
212precede and \fB\-pkeyopt\fR options. The options \fB\-paramfile\fR and \fB\-algorithm\fR
213are mutually exclusive.
214.IP "\fB\-text\fR" 4
215.IX Item "-text"
216Print an (unencrypted) text representation of private and public keys and
217parameters along with the \s-1PEM\s0 or \s-1DER\s0 structure.
218.SH "KEY GENERATION OPTIONS"
219.IX Header "KEY GENERATION OPTIONS"
220The options supported by each algorith and indeed each implementation of an
221algorithm can vary. The options for the OpenSSL implementations are detailed
222below.
223.SS "\s-1RSA\s0 Key Generation Options"
224.IX Subsection "RSA Key Generation Options"
225.IP "\fBrsa_keygen_bits:numbits\fR" 4
226.IX Item "rsa_keygen_bits:numbits"
227The number of bits in the generated key. If not specified 1024 is used.
228.IP "\fBrsa_keygen_pubexp:value\fR" 4
229.IX Item "rsa_keygen_pubexp:value"
230The \s-1RSA\s0 public exponent value. This can be a large decimal or
231hexadecimal value if preceded by \fB0x\fR. Default value is 65537.
232.SS "\s-1EC\s0 Key Generation Options"
233.IX Subsection "EC Key Generation Options"
234The \s-1EC\s0 key generation options can also be used for parameter generation.
235.IP "\fBec_paramgen_curve:curve\fR" 4
236.IX Item "ec_paramgen_curve:curve"
237The \s-1EC\s0 curve to use. OpenSSL supports \s-1NIST\s0 curve names such as \*(L"P\-256\*(R".
238.IP "\fBec_param_enc:encoding\fR" 4
239.IX Item "ec_param_enc:encoding"
240The encoding to use for parameters. The \*(L"encoding\*(R" parameter must be either
241\&\*(L"named_curve\*(R" or \*(L"explicit\*(R". The default value is \*(L"named_curve\*(R".
242.SH "PARAMETER GENERATION OPTIONS"
243.IX Header "PARAMETER GENERATION OPTIONS"
244The options supported by each algorithm and indeed each implementation of an
245algorithm can vary. The options for the OpenSSL implementations are detailed
246below.
247.SS "\s-1DSA\s0 Parameter Generation Options"
248.IX Subsection "DSA Parameter Generation Options"
249.IP "\fBdsa_paramgen_bits:numbits\fR" 4
250.IX Item "dsa_paramgen_bits:numbits"
251The number of bits in the generated prime. If not specified 1024 is used.
252.IP "\fBdsa_paramgen_q_bits:numbits\fR" 4
253.IX Item "dsa_paramgen_q_bits:numbits"
254The number of bits in the q parameter. Must be one of 160, 224 or 256. If not
255specified 160 is used.
256.IP "\fBdsa_paramgen_md:digest\fR" 4
257.IX Item "dsa_paramgen_md:digest"
258The digest to use during parameter generation. Must be one of \fBsha1\fR, \fBsha224\fR
259or \fBsha256\fR. If set, then the number of bits in \fBq\fR will match the output size
260of the specified digest and the \fBdsa_paramgen_q_bits\fR parameter will be
261ignored. If not set, then a digest will be used that gives an output matching
262the number of bits in \fBq\fR, i.e. \fBsha1\fR if q length is 160, \fBsha224\fR if it 224
263or \fBsha256\fR if it is 256.
264.SS "\s-1DH\s0 Parameter Generation Options"
265.IX Subsection "DH Parameter Generation Options"
266.IP "\fBdh_paramgen_prime_len:numbits\fR" 4
267.IX Item "dh_paramgen_prime_len:numbits"
268The number of bits in the prime parameter \fBp\fR. The default is 1024.
269.IP "\fBdh_paramgen_subprime_len:numbits\fR" 4
270.IX Item "dh_paramgen_subprime_len:numbits"
271The number of bits in the sub prime parameter \fBq\fR. The default is 256 if the
272prime is at least 2048 bits long or 160 otherwise. Only relevant if used in
273conjunction with the \fBdh_paramgen_type\fR option to generate X9.42 \s-1DH\s0 parameters.
274.IP "\fBdh_paramgen_generator:value\fR" 4
275.IX Item "dh_paramgen_generator:value"
276The value to use for the generator \fBg\fR. The default is 2.
277.IP "\fBdh_paramgen_type:value\fR" 4
278.IX Item "dh_paramgen_type:value"
279The type of \s-1DH\s0 parameters to generate. Use 0 for PKCS#3 \s-1DH\s0 and 1 for X9.42 \s-1DH.\s0
280The default is 0.
281.IP "\fBdh_rfc5114:num\fR" 4
282.IX Item "dh_rfc5114:num"
283If this option is set, then the appropriate \s-1RFC5114\s0 parameters are used
284instead of generating new parameters. The value \fBnum\fR can take the
285values 1, 2 or 3 corresponding to \s-1RFC5114 DH\s0 parameters consisting of
2861024 bit group with 160 bit subgroup, 2048 bit group with 224 bit subgroup
287and 2048 bit group with 256 bit subgroup as mentioned in \s-1RFC5114\s0 sections
2882.1, 2.2 and 2.3 respectively. If present this overrides all other \s-1DH\s0 parameter
289options.
290.SS "\s-1EC\s0 Parameter Generation Options"
291.IX Subsection "EC Parameter Generation Options"
292The \s-1EC\s0 parameter generation options are the same as for key generation. See
293\&\*(L"\s-1EC\s0 Key Generation Options\*(R" above.
294.SH "GOST2001 KEY GENERATION AND PARAMETER OPTIONS"
295.IX Header "GOST2001 KEY GENERATION AND PARAMETER OPTIONS"
296Gost 2001 support is not enabled by default. To enable this algorithm,
297one should load the ccgost engine in the OpenSSL configuration file.
298See \s-1README\s0.gost file in the engines/ccgost directiry of the source
299distribution for more details.
300.PP
301Use of a parameter file for the \s-1GOST R 34.10\s0 algorithm is optional.
302Parameters can be specified during key generation directly as well as
303during generation of parameter file.
304.IP "\fBparamset:name\fR" 4
305.IX Item "paramset:name"
306Specifies \s-1GOST R 34.10\-2001\s0 parameter set according to \s-1RFC 4357.\s0
307Parameter set can be specified using abbreviated name, object short name or
308numeric \s-1OID.\s0 Following parameter sets are supported:
309.Sp
310.Vb 7
311\& paramset OID Usage
312\& A 1.2.643.2.2.35.1 Signature
313\& B 1.2.643.2.2.35.2 Signature
314\& C 1.2.643.2.2.35.3 Signature
315\& XA 1.2.643.2.2.36.0 Key exchange
316\& XB 1.2.643.2.2.36.1 Key exchange
317\& test 1.2.643.2.2.35.0 Test purposes
318.Ve
319.SH "NOTES"
320.IX Header "NOTES"
321The use of the genpkey program is encouraged over the algorithm specific
322utilities because additional algorithm options and \s-1ENGINE\s0 provided algorithms
323can be used.
324.SH "EXAMPLES"
325.IX Header "EXAMPLES"
326Generate an \s-1RSA\s0 private key using default parameters:
327.PP
328.Vb 1
329\& openssl genpkey \-algorithm RSA \-out key.pem
330.Ve
331.PP
332Encrypt output private key using 128 bit \s-1AES\s0 and the passphrase \*(L"hello\*(R":
333.PP
334.Vb 1
335\& openssl genpkey \-algorithm RSA \-out key.pem \-aes\-128\-cbc \-pass pass:hello
336.Ve
337.PP
338Generate a 2048 bit \s-1RSA\s0 key using 3 as the public exponent:
339.PP
340.Vb 2
341\& openssl genpkey \-algorithm RSA \-out key.pem \-pkeyopt rsa_keygen_bits:2048 \e
342\& \-pkeyopt rsa_keygen_pubexp:3
343.Ve
344.PP
345Generate 2048 bit \s-1DSA\s0 parameters:
346.PP
347.Vb 2
348\& openssl genpkey \-genparam \-algorithm DSA \-out dsap.pem \e
349\& \-pkeyopt dsa_paramgen_bits:2048
350.Ve
351.PP
352Generate \s-1DSA\s0 key from parameters:
353.PP
354.Vb 1
355\& openssl genpkey \-paramfile dsap.pem \-out dsakey.pem
356.Ve
357.PP
358Generate 2048 bit \s-1DH\s0 parameters:
359.PP
360.Vb 2
361\& openssl genpkey \-genparam \-algorithm DH \-out dhp.pem \e
362\& \-pkeyopt dh_paramgen_prime_len:2048
363.Ve
364.PP
365Generate 2048 bit X9.42 \s-1DH\s0 parameters:
366.PP
367.Vb 3
368\& openssl genpkey \-genparam \-algorithm DH \-out dhpx.pem \e
369\& \-pkeyopt dh_paramgen_prime_len:2048 \e
370\& \-pkeyopt dh_paramgen_type:1
371.Ve
372.PP
373Output \s-1RFC5114 2048\s0 bit \s-1DH\s0 parameters with 224 bit subgroup:
374.PP
375.Vb 1
376\& openssl genpkey \-genparam \-algorithm DH \-out dhp.pem \-pkeyopt dh_rfc5114:2
377.Ve
378.PP
379Generate \s-1DH\s0 key from parameters:
380.PP
381.Vb 1
382\& openssl genpkey \-paramfile dhp.pem \-out dhkey.pem
383.Ve
384.PP
385Generate \s-1EC\s0 key directly:
386.PP
387.Vb 3
388\& openssl genpkey \-algorithm EC \-out eckey.pem \e
389\& \-pkeyopt ec_paramgen_curve:P\-384 \e
390\& \-pkeyopt ec_param_enc:named_curve
391.Ve
392.SH "HISTORY"
393.IX Header "HISTORY"
394The ability to use \s-1NIST\s0 curve names, and to generate an \s-1EC\s0 key directly,
395were added in OpenSSL 1.0.2.
2.\"
3.\" Standard preamble:
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18.\" Set up some character translations and predefined strings. \*(-- will
19.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
20.\" double quote, and \*(R" will give a right double quote. \*(C+ will
21.\" give a nicer C++. Capital omega is used to do unbreakable dashes and
22.\" therefore won't be available. \*(C` and \*(C' expand to `' in nroff,
23.\" nothing in troff, for use with C<>.
24.tr \(*W-
25.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
26.ie n \{\
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36.el\{\
37. ds -- \|\(em\|
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43'br\}
44.\"
45.\" Escape single quotes in literal strings from groff's Unicode transform.
46.ie \n(.g .ds Aq \(aq
47.el .ds Aq '
48.\"
49.\" If the F register is >0, we'll generate index entries on stderr for
50.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
51.\" entries marked with X<> in POD. Of course, you'll have to process the
52.\" output yourself in some meaningful fashion.
53.\"
54.\" Avoid warning from groff about undefined register 'F'.
55.de IX
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57.if !\nF .nr F 0
58.if \nF>0 \{\
59. de IX
60. tm Index:\\$1\t\\n%\t"\\$2"
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63. nr % 0
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65. \}
66.\}
67.\"
68.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
69.\" Fear. Run. Save yourself. No user-serviceable parts.
70. \" fudge factors for nroff and troff
71.if n \{\
72. ds #H 0
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109.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
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129.\" ========================================================================
130.\"
131.IX Title "GENPKEY 1"
132.TH GENPKEY 1 "2018-08-14" "1.0.2p" "OpenSSL"
133.\" For nroff, turn off justification. Always turn off hyphenation; it makes
134.\" way too many mistakes in technical documents.
135.if n .ad l
136.nh
137.SH "NAME"
138openssl\-genpkey,
139genpkey \- generate a private key
140.SH "SYNOPSIS"
141.IX Header "SYNOPSIS"
142\&\fBopenssl\fR \fBgenpkey\fR
143[\fB\-out filename\fR]
144[\fB\-outform PEM|DER\fR]
145[\fB\-pass arg\fR]
146[\fB\-\f(BIcipher\fB\fR]
147[\fB\-engine id\fR]
148[\fB\-paramfile file\fR]
149[\fB\-algorithm alg\fR]
150[\fB\-pkeyopt opt:value\fR]
151[\fB\-genparam\fR]
152[\fB\-text\fR]
153.SH "DESCRIPTION"
154.IX Header "DESCRIPTION"
155The \fBgenpkey\fR command generates a private key.
156.SH "OPTIONS"
157.IX Header "OPTIONS"
158.IP "\fB\-out filename\fR" 4
159.IX Item "-out filename"
160the output filename. If this argument is not specified then standard output is
161used.
162.IP "\fB\-outform DER|PEM\fR" 4
163.IX Item "-outform DER|PEM"
164This specifies the output format \s-1DER\s0 or \s-1PEM.\s0 The default format is \s-1PEM.\s0
165.IP "\fB\-pass arg\fR" 4
166.IX Item "-pass arg"
167The output file password source. For more information about the format of \fBarg\fR
168see the \fB\s-1PASS PHRASE ARGUMENTS\s0\fR section in \fIopenssl\fR\|(1).
169.IP "\fB\-\f(BIcipher\fB\fR" 4
170.IX Item "-cipher"
171This option encrypts the private key with the supplied cipher. Any algorithm
172name accepted by \fIEVP_get_cipherbyname()\fR is acceptable such as \fBdes3\fR.
173.IP "\fB\-engine id\fR" 4
174.IX Item "-engine id"
175Specifying an engine (by its unique \fBid\fR string) will cause \fBgenpkey\fR
176to attempt to obtain a functional reference to the specified engine,
177thus initialising it if needed. The engine will then be set as the default
178for all available algorithms. If used this option should precede all other
179options.
180.IP "\fB\-algorithm alg\fR" 4
181.IX Item "-algorithm alg"
182Public key algorithm to use such as \s-1RSA, DSA\s0 or \s-1DH.\s0 If used this option must
183precede any \fB\-pkeyopt\fR options. The options \fB\-paramfile\fR and \fB\-algorithm\fR
184are mutually exclusive. Engines may add algorithms in addition to the standard
185built-in ones.
186.Sp
187Valid built-in algorithm names for private key generation are \s-1RSA\s0 and \s-1EC.\s0
188.Sp
189Valid built-in algorithm names for parameter generation (see the \fB\-genparam\fR
190option) are \s-1DH, DSA\s0 and \s-1EC.\s0
191.Sp
192Note that the algorithm name X9.42 \s-1DH\s0 may be used as a synonym for the \s-1DH\s0
193algorithm. These are identical and do not indicate the type of parameters that
194will be generated. Use the \fBdh_paramgen_type\fR option to indicate whether PKCS#3
195or X9.42 \s-1DH\s0 parameters are required. See \*(L"\s-1DH\s0 Parameter Generation Options\*(R"
196below for more details.
197.IP "\fB\-pkeyopt opt:value\fR" 4
198.IX Item "-pkeyopt opt:value"
199Set the public key algorithm option \fBopt\fR to \fBvalue\fR. The precise set of
200options supported depends on the public key algorithm used and its
201implementation. See \*(L"\s-1KEY GENERATION OPTIONS\*(R"\s0 and
202\&\*(L"\s-1PARAMETER GENERATION OPTIONS\*(R"\s0 below for more details.
203.IP "\fB\-genparam\fR" 4
204.IX Item "-genparam"
205Generate a set of parameters instead of a private key. If used this option must
206precede any \fB\-algorithm\fR, \fB\-paramfile\fR or \fB\-pkeyopt\fR options.
207.IP "\fB\-paramfile filename\fR" 4
208.IX Item "-paramfile filename"
209Some public key algorithms generate a private key based on a set of parameters.
210They can be supplied using this option. If this option is used the public key
211algorithm used is determined by the parameters. If used this option must
212precede and \fB\-pkeyopt\fR options. The options \fB\-paramfile\fR and \fB\-algorithm\fR
213are mutually exclusive.
214.IP "\fB\-text\fR" 4
215.IX Item "-text"
216Print an (unencrypted) text representation of private and public keys and
217parameters along with the \s-1PEM\s0 or \s-1DER\s0 structure.
218.SH "KEY GENERATION OPTIONS"
219.IX Header "KEY GENERATION OPTIONS"
220The options supported by each algorith and indeed each implementation of an
221algorithm can vary. The options for the OpenSSL implementations are detailed
222below.
223.SS "\s-1RSA\s0 Key Generation Options"
224.IX Subsection "RSA Key Generation Options"
225.IP "\fBrsa_keygen_bits:numbits\fR" 4
226.IX Item "rsa_keygen_bits:numbits"
227The number of bits in the generated key. If not specified 1024 is used.
228.IP "\fBrsa_keygen_pubexp:value\fR" 4
229.IX Item "rsa_keygen_pubexp:value"
230The \s-1RSA\s0 public exponent value. This can be a large decimal or
231hexadecimal value if preceded by \fB0x\fR. Default value is 65537.
232.SS "\s-1EC\s0 Key Generation Options"
233.IX Subsection "EC Key Generation Options"
234The \s-1EC\s0 key generation options can also be used for parameter generation.
235.IP "\fBec_paramgen_curve:curve\fR" 4
236.IX Item "ec_paramgen_curve:curve"
237The \s-1EC\s0 curve to use. OpenSSL supports \s-1NIST\s0 curve names such as \*(L"P\-256\*(R".
238.IP "\fBec_param_enc:encoding\fR" 4
239.IX Item "ec_param_enc:encoding"
240The encoding to use for parameters. The \*(L"encoding\*(R" parameter must be either
241\&\*(L"named_curve\*(R" or \*(L"explicit\*(R". The default value is \*(L"named_curve\*(R".
242.SH "PARAMETER GENERATION OPTIONS"
243.IX Header "PARAMETER GENERATION OPTIONS"
244The options supported by each algorithm and indeed each implementation of an
245algorithm can vary. The options for the OpenSSL implementations are detailed
246below.
247.SS "\s-1DSA\s0 Parameter Generation Options"
248.IX Subsection "DSA Parameter Generation Options"
249.IP "\fBdsa_paramgen_bits:numbits\fR" 4
250.IX Item "dsa_paramgen_bits:numbits"
251The number of bits in the generated prime. If not specified 1024 is used.
252.IP "\fBdsa_paramgen_q_bits:numbits\fR" 4
253.IX Item "dsa_paramgen_q_bits:numbits"
254The number of bits in the q parameter. Must be one of 160, 224 or 256. If not
255specified 160 is used.
256.IP "\fBdsa_paramgen_md:digest\fR" 4
257.IX Item "dsa_paramgen_md:digest"
258The digest to use during parameter generation. Must be one of \fBsha1\fR, \fBsha224\fR
259or \fBsha256\fR. If set, then the number of bits in \fBq\fR will match the output size
260of the specified digest and the \fBdsa_paramgen_q_bits\fR parameter will be
261ignored. If not set, then a digest will be used that gives an output matching
262the number of bits in \fBq\fR, i.e. \fBsha1\fR if q length is 160, \fBsha224\fR if it 224
263or \fBsha256\fR if it is 256.
264.SS "\s-1DH\s0 Parameter Generation Options"
265.IX Subsection "DH Parameter Generation Options"
266.IP "\fBdh_paramgen_prime_len:numbits\fR" 4
267.IX Item "dh_paramgen_prime_len:numbits"
268The number of bits in the prime parameter \fBp\fR. The default is 1024.
269.IP "\fBdh_paramgen_subprime_len:numbits\fR" 4
270.IX Item "dh_paramgen_subprime_len:numbits"
271The number of bits in the sub prime parameter \fBq\fR. The default is 256 if the
272prime is at least 2048 bits long or 160 otherwise. Only relevant if used in
273conjunction with the \fBdh_paramgen_type\fR option to generate X9.42 \s-1DH\s0 parameters.
274.IP "\fBdh_paramgen_generator:value\fR" 4
275.IX Item "dh_paramgen_generator:value"
276The value to use for the generator \fBg\fR. The default is 2.
277.IP "\fBdh_paramgen_type:value\fR" 4
278.IX Item "dh_paramgen_type:value"
279The type of \s-1DH\s0 parameters to generate. Use 0 for PKCS#3 \s-1DH\s0 and 1 for X9.42 \s-1DH.\s0
280The default is 0.
281.IP "\fBdh_rfc5114:num\fR" 4
282.IX Item "dh_rfc5114:num"
283If this option is set, then the appropriate \s-1RFC5114\s0 parameters are used
284instead of generating new parameters. The value \fBnum\fR can take the
285values 1, 2 or 3 corresponding to \s-1RFC5114 DH\s0 parameters consisting of
2861024 bit group with 160 bit subgroup, 2048 bit group with 224 bit subgroup
287and 2048 bit group with 256 bit subgroup as mentioned in \s-1RFC5114\s0 sections
2882.1, 2.2 and 2.3 respectively. If present this overrides all other \s-1DH\s0 parameter
289options.
290.SS "\s-1EC\s0 Parameter Generation Options"
291.IX Subsection "EC Parameter Generation Options"
292The \s-1EC\s0 parameter generation options are the same as for key generation. See
293\&\*(L"\s-1EC\s0 Key Generation Options\*(R" above.
294.SH "GOST2001 KEY GENERATION AND PARAMETER OPTIONS"
295.IX Header "GOST2001 KEY GENERATION AND PARAMETER OPTIONS"
296Gost 2001 support is not enabled by default. To enable this algorithm,
297one should load the ccgost engine in the OpenSSL configuration file.
298See \s-1README\s0.gost file in the engines/ccgost directiry of the source
299distribution for more details.
300.PP
301Use of a parameter file for the \s-1GOST R 34.10\s0 algorithm is optional.
302Parameters can be specified during key generation directly as well as
303during generation of parameter file.
304.IP "\fBparamset:name\fR" 4
305.IX Item "paramset:name"
306Specifies \s-1GOST R 34.10\-2001\s0 parameter set according to \s-1RFC 4357.\s0
307Parameter set can be specified using abbreviated name, object short name or
308numeric \s-1OID.\s0 Following parameter sets are supported:
309.Sp
310.Vb 7
311\& paramset OID Usage
312\& A 1.2.643.2.2.35.1 Signature
313\& B 1.2.643.2.2.35.2 Signature
314\& C 1.2.643.2.2.35.3 Signature
315\& XA 1.2.643.2.2.36.0 Key exchange
316\& XB 1.2.643.2.2.36.1 Key exchange
317\& test 1.2.643.2.2.35.0 Test purposes
318.Ve
319.SH "NOTES"
320.IX Header "NOTES"
321The use of the genpkey program is encouraged over the algorithm specific
322utilities because additional algorithm options and \s-1ENGINE\s0 provided algorithms
323can be used.
324.SH "EXAMPLES"
325.IX Header "EXAMPLES"
326Generate an \s-1RSA\s0 private key using default parameters:
327.PP
328.Vb 1
329\& openssl genpkey \-algorithm RSA \-out key.pem
330.Ve
331.PP
332Encrypt output private key using 128 bit \s-1AES\s0 and the passphrase \*(L"hello\*(R":
333.PP
334.Vb 1
335\& openssl genpkey \-algorithm RSA \-out key.pem \-aes\-128\-cbc \-pass pass:hello
336.Ve
337.PP
338Generate a 2048 bit \s-1RSA\s0 key using 3 as the public exponent:
339.PP
340.Vb 2
341\& openssl genpkey \-algorithm RSA \-out key.pem \-pkeyopt rsa_keygen_bits:2048 \e
342\& \-pkeyopt rsa_keygen_pubexp:3
343.Ve
344.PP
345Generate 2048 bit \s-1DSA\s0 parameters:
346.PP
347.Vb 2
348\& openssl genpkey \-genparam \-algorithm DSA \-out dsap.pem \e
349\& \-pkeyopt dsa_paramgen_bits:2048
350.Ve
351.PP
352Generate \s-1DSA\s0 key from parameters:
353.PP
354.Vb 1
355\& openssl genpkey \-paramfile dsap.pem \-out dsakey.pem
356.Ve
357.PP
358Generate 2048 bit \s-1DH\s0 parameters:
359.PP
360.Vb 2
361\& openssl genpkey \-genparam \-algorithm DH \-out dhp.pem \e
362\& \-pkeyopt dh_paramgen_prime_len:2048
363.Ve
364.PP
365Generate 2048 bit X9.42 \s-1DH\s0 parameters:
366.PP
367.Vb 3
368\& openssl genpkey \-genparam \-algorithm DH \-out dhpx.pem \e
369\& \-pkeyopt dh_paramgen_prime_len:2048 \e
370\& \-pkeyopt dh_paramgen_type:1
371.Ve
372.PP
373Output \s-1RFC5114 2048\s0 bit \s-1DH\s0 parameters with 224 bit subgroup:
374.PP
375.Vb 1
376\& openssl genpkey \-genparam \-algorithm DH \-out dhp.pem \-pkeyopt dh_rfc5114:2
377.Ve
378.PP
379Generate \s-1DH\s0 key from parameters:
380.PP
381.Vb 1
382\& openssl genpkey \-paramfile dhp.pem \-out dhkey.pem
383.Ve
384.PP
385Generate \s-1EC\s0 key directly:
386.PP
387.Vb 3
388\& openssl genpkey \-algorithm EC \-out eckey.pem \e
389\& \-pkeyopt ec_paramgen_curve:P\-384 \e
390\& \-pkeyopt ec_param_enc:named_curve
391.Ve
392.SH "HISTORY"
393.IX Header "HISTORY"
394The ability to use \s-1NIST\s0 curve names, and to generate an \s-1EC\s0 key directly,
395were added in OpenSSL 1.0.2.