1=pod
2
3=head1 NAME
4
5pkeyutl - public key algorithm utility
6
7=head1 SYNOPSIS
8
9B<openssl> B<pkeyutl>
10[B<-in file>]
11[B<-out file>]
12[B<-sigfile file>]
13[B<-inkey file>]
14[B<-keyform PEM|DER>]
15[B<-passin arg>]
16[B<-peerkey file>]
17[B<-peerform PEM|DER>]
18[B<-pubin>]
19[B<-certin>]
20[B<-rev>]
21[B<-sign>]
22[B<-verify>]
23[B<-verifyrecover>]
24[B<-encrypt>]
25[B<-decrypt>]
26[B<-derive>]
27[B<-pkeyopt opt:value>]
28[B<-hexdump>]
29[B<-asn1parse>]
30[B<-engine id>]
31
32=head1 DESCRIPTION
33
34The B<pkeyutl> command can be used to perform public key operations using
35any supported algorithm.
36
37=head1 COMMAND OPTIONS
38
39=over 4
40
41=item B<-in filename>
42
43This specifies the input filename to read data from or standard input
44if this option is not specified.
45
46=item B<-out filename>
47
48specifies the output filename to write to or standard output by
49default.
50
51=item B<-inkey file>
52
53the input key file, by default it should be a private key.
54
55=item B<-keyform PEM|DER>
56
57the key format PEM, DER or ENGINE.
58
59=item B<-passin arg>
60
61the input key password source. For more information about the format of B<arg>
62see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
63
64
65=item B<-peerkey file>
66
67the peer key file, used by key derivation (agreement) operations.
68
69=item B<-peerform PEM|DER>
70
71the peer key format PEM, DER or ENGINE.
72
73=item B<-engine id>
74
75specifying an engine (by its unique B<id> string) will cause B<pkeyutl>
76to attempt to obtain a functional reference to the specified engine,
77thus initialising it if needed. The engine will then be set as the default
78for all available algorithms.
79
80
81=item B<-pubin>
82
83the input file is a public key.
84
85=item B<-certin>
86
87the input is a certificate containing a public key.
88
89=item B<-rev>
90
91reverse the order of the input buffer. This is useful for some libraries
92(such as CryptoAPI) which represent the buffer in little endian format.
93
94=item B<-sign>
95
96sign the input data and output the signed result. This requires
97a private key.
98
99=item B<-verify>
100
101verify the input data against the signature file and indicate if the
102verification succeeded or failed.
103
104=item B<-verifyrecover>
105
106verify the input data and output the recovered data.
107
108=item B<-encrypt>
109
110encrypt the input data using a public key.
111
112=item B<-decrypt>
113
114decrypt the input data using a private key.
115
116=item B<-derive>
117
118derive a shared secret using the peer key.
119
120=item B<-hexdump>
121
122hex dump the output data.
123
124=item B<-asn1parse>
125
126asn1parse the output data, this is useful when combined with the
127B<-verifyrecover> option when an ASN1 structure is signed.
128
129=back
130
131=head1 NOTES
132
133The operations and options supported vary according to the key algorithm
134and its implementation. The OpenSSL operations and options are indicated below.
135
136Unless otherwise mentioned all algorithms support the B<digest:alg> option
137which specifies the digest in use for sign, verify and verifyrecover operations.
138The value B<alg> should represent a digest name as used in the
139EVP_get_digestbyname() function for example B<sha1>.
140
141=head1 RSA ALGORITHM
142
143The RSA algorithm supports encrypt, decrypt, sign, verify and verifyrecover
144operations in general. Some padding modes only support some of these
145operations however.
146
147=over 4
148
149=item -B<rsa_padding_mode:mode>
150
151This sets the RSA padding mode. Acceptable values for B<mode> are B<pkcs1> for
152PKCS#1 padding, B<sslv23> for SSLv23 padding, B<none> for no padding, B<oaep>
153for B<OAEP> mode, B<x931> for X9.31 mode and B<pss> for PSS.
154
155In PKCS#1 padding if the message digest is not set then the supplied data is
156signed or verified directly instead of using a B<DigestInfo> structure. If a
157digest is set then the a B<DigestInfo> structure is used and its the length
158must correspond to the digest type.
159
160For B<oeap> mode only encryption and decryption is supported.
161
162For B<x931> if the digest type is set it is used to format the block data
163otherwise the first byte is used to specify the X9.31 digest ID. Sign,
164verify and verifyrecover are can be performed in this mode.
165
166For B<pss> mode only sign and verify are supported and the digest type must be
167specified.
168
169=item B<rsa_pss_saltlen:len>
170
171For B<pss> mode only this option specifies the salt length. Two special values
172are supported: -1 sets the salt length to the digest length. When signing -2
173sets the salt length to the maximum permissible value. When verifying -2 causes
174the salt length to be automatically determined based on the B<PSS> block
175structure.
176
177=back
178
179=head1 DSA ALGORITHM
180
181The DSA algorithm supports signing and verification operations only. Currently
182there are no additional options other than B<digest>. Only the SHA1
183digest can be used and this digest is assumed by default.
184
185=head1 DH ALGORITHM
186
187The DH algorithm only supports the derivation operation and no additional
188options.
189
190=head1 EC ALGORITHM
191
192The EC algorithm supports sign, verify and derive operations. The sign and
193verify operations use ECDSA and derive uses ECDH. Currently there are no
194additional options other than B<digest>. Only the SHA1 digest can be used and
195this digest is assumed by default.
196
197=head1 EXAMPLES
198
199Sign some data using a private key:
200
201 openssl pkeyutl -sign -in file -inkey key.pem -out sig
202
203Recover the signed data (e.g. if an RSA key is used):
204
205 openssl pkeyutl -verifyrecover -in sig -inkey key.pem
206
207Verify the signature (e.g. a DSA key):
208
209 openssl pkeyutl -verify -in file -sigfile sig -inkey key.pem
210
211Sign data using a message digest value (this is currently only valid for RSA):
212
213 openssl pkeyutl -sign -in file -inkey key.pem -out sig -pkeyopt digest:sha256
214
215Derive a shared secret value:
216
217 openssl pkeyutl -derive -inkey key.pem -peerkey pubkey.pem -out secret
218
219=head1 SEE ALSO
220
221L<genpkey(1)|genpkey(1)>, L<pkey(1)|pkey(1)>, L<rsautl(1)|rsautl(1)>
222L<dgst(1)|dgst(1)>, L<rsa(1)|rsa(1)>, L<genrsa(1)|genrsa(1)>
223