1GENPKEY(1) OpenSSL GENPKEY(1)
2
6 genpkey - generate a private key
7
9 openssl genpkey [-out filename] [-outform PEM|DER] [-pass arg]
10 [-cipher] [-engine id] [-paramfile file] [-algorithm alg] [-pkeyopt
11 opt:value] [-genparam] [-text]
12
14 The genpkey command generates a private key.
15
17 -out filename
18 the output filename. If this argument is not specified then
19 standard output is used.
20 -outform DER|PEM
22 This specifies the output format DER or PEM.
23 -pass arg
25 the output file password source. For more information about the
26 format of arg see the PASS PHRASE ARGUMENTS section in openssl(1).
27 -cipher
29 This option encrypts the private key with the supplied cipher. Any
30 algorithm name accepted by EVP_get_cipherbyname() is acceptable
31 such as des3.
32 -engine id
34 specifying an engine (by its unique id string) will cause genpkey
35 to attempt to obtain a functional reference to the specified
36 engine, thus initialising it if needed. The engine will then be set
37 as the default for all available algorithms. If used this option
38 should precede all other options.
39 -algorithm alg
41 public key algorithm to use such as RSA, DSA or DH. If used this
42 option must precede any -pkeyopt options. The options -paramfile
43 and -algorithm are mutually exclusive.
44 -pkeyopt opt:value
46 set the public key algorithm option opt to value. The precise set
47 of options supported depends on the public key algorithm used and
48 its implementation. See KEY GENERATION OPTIONS below for more
49 details.
50 -genparam
52 generate a set of parameters instead of a private key. If used this
53 option must precede and -algorithm, -paramfile or -pkeyopt options.
54 -paramfile filename
56 Some public key algorithms generate a private key based on a set of
57 parameters. They can be supplied using this option. If this option
58 is used the public key algorithm used is determined by the
59 parameters. If used this option must precede and -pkeyopt options.
60 The options -paramfile and -algorithm are mutually exclusive.
61 -text
63 Print an (unencrypted) text representation of private and public
64 keys and parameters along with the PEM or DER structure.
65
67 The options supported by each algorith and indeed each implementation
68 of an algorithm can vary. The options for the OpenSSL implementations
69 are detailed below.
70
72 rsa_keygen_bits:numbits
73 The number of bits in the generated key. If not specified 1024 is
74 used.
75 rsa_keygen_pubexp:value
77 The RSA public exponent value. This can be a large decimal or
78 hexadecimal value if preceded by 0x. Default value is 65537.
79
81 dsa_paramgen_bits:numbits
82 The number of bits in the generated parameters. If not specified
83 1024 is used.
84
86 dh_paramgen_prime_len:numbits
87 The number of bits in the prime parameter p.
88 dh_paramgen_generator:value
90 The value to use for the generator g.
91 dh_rfc5114:num
93 If this option is set then the appropriate RFC5114 parameters are
94 used instead of generating new parameters. The value num can take
95 the values 1, 2 or 3 corresponding to RFC5114 DH parameters
96 consisting of 1024 bit group with 160 bit subgroup, 2048 bit group
97 with 224 bit subgroup and 2048 bit group with 256 bit subgroup as
98 mentioned in RFC5114 sections 2.1, 2.2 and 2.3 respectively.
99
101 ec_paramgen_curve:curve
102 the EC curve to use.
103
105 Gost 2001 support is not enabled by default. To enable this algorithm,
106 one should load the ccgost engine in the OpenSSL configuration file.
107 See README.gost file in the engines/ccgost directiry of the source
108 distribution for more details.
109 Use of a parameter file for the GOST R 34.10 algorithm is optional.
111 Parameters can be specified during key generation directly as well as
112 during generation of parameter file.
113 paramset:name
115 Specifies GOST R 34.10-2001 parameter set according to RFC 4357.
116 Parameter set can be specified using abbreviated name, object short
117 name or numeric OID. Following parameter sets are supported:
118 paramset OID Usage
120 A 1.2.643.2.2.35.1 Signature
121 B 1.2.643.2.2.35.2 Signature
122 C 1.2.643.2.2.35.3 Signature
123 XA 1.2.643.2.2.36.0 Key exchange
124 XB 1.2.643.2.2.36.1 Key exchange
125 test 1.2.643.2.2.35.0 Test purposes
126
128 The use of the genpkey program is encouraged over the algorithm
129 specific utilities because additional algorithm options and ENGINE
130 provided algorithms can be used.
131
133 Generate an RSA private key using default parameters:
134 openssl genpkey -algorithm RSA -out key.pem
136 Encrypt output private key using 128 bit AES and the passphrase
138 "hello":
139 openssl genpkey -algorithm RSA -out key.pem -aes-128-cbc -pass pass:hello
141 Generate a 2048 bit RSA key using 3 as the public exponent:
143 openssl genpkey -algorithm RSA -out key.pem -pkeyopt rsa_keygen_bits:2048 \
145 -pkeyopt rsa_keygen_pubexp:3
146 Generate 1024 bit DSA parameters:
148 openssl genpkey -genparam -algorithm DSA -out dsap.pem \
150 -pkeyopt dsa_paramgen_bits:1024
151 Generate DSA key from parameters:
153 openssl genpkey -paramfile dsap.pem -out dsakey.pem
155 Generate 1024 bit DH parameters:
157 openssl genpkey -genparam -algorithm DH -out dhp.pem \
159 -pkeyopt dh_paramgen_prime_len:1024
160 Output RFC5114 2048 bit DH parameters with 224 bit subgroup:
162 openssl genpkey -genparam -algorithm DH -out dhp.pem -pkeyopt dh_rfc5114:2
164 Generate DH key from parameters:
166 openssl genpkey -paramfile dhp.pem -out dhkey.pem
1681.0.2k 2017-01-26 GENPKEY(1)