1EC(1) OpenSSL EC(1)
2
6 openssl-ec, ec - EC key processing
7
9 openssl ec [-help] [-inform PEM|DER] [-outform PEM|DER] [-in filename]
10 [-passin arg] [-out filename] [-passout arg] [-des] [-des3] [-idea]
11 [-text] [-noout] [-param_out] [-pubin] [-pubout] [-conv_form arg]
12 [-param_enc arg] [-no_public] [-check] [-engine id]
13
15 The ec command processes EC keys. They can be converted between various
16 forms and their components printed out. Note OpenSSL uses the private
17 key format specified in 'SEC 1: Elliptic Curve Cryptography'
18 (http://www.secg.org/). To convert an OpenSSL EC private key into the
19 PKCS#8 private key format use the pkcs8 command.
20
22 -help
23 Print out a usage message.
24 -inform DER|PEM
26 This specifies the input format. The DER option with a private key
27 uses an ASN.1 DER encoded SEC1 private key. When used with a public
28 key it uses the SubjectPublicKeyInfo structure as specified in RFC
29 3280. The PEM form is the default format: it consists of the DER
30 format base64 encoded with additional header and footer lines. In
31 the case of a private key PKCS#8 format is also accepted.
32 -outform DER|PEM
34 This specifies the output format, the options have the same meaning
35 and default as the -inform option.
36 -in filename
38 This specifies the input filename to read a key from or standard
39 input if this option is not specified. If the key is encrypted a
40 pass phrase will be prompted for.
41 -passin arg
43 The input file password source. For more information about the
44 format of arg see the PASS PHRASE ARGUMENTS section in openssl(1).
45 -out filename
47 This specifies the output filename to write a key to or standard
48 output by is not specified. If any encryption options are set then
49 a pass phrase will be prompted for. The output filename should not
50 be the same as the input filename.
51 -passout arg
53 The output file password source. For more information about the
54 format of arg see the PASS PHRASE ARGUMENTS section in openssl(1).
55 -des|-des3|-idea
57 These options encrypt the private key with the DES, triple DES,
58 IDEA or any other cipher supported by OpenSSL before outputting it.
59 A pass phrase is prompted for. If none of these options is
60 specified the key is written in plain text. This means that using
61 the ec utility to read in an encrypted key with no encryption
62 option can be used to remove the pass phrase from a key, or by
63 setting the encryption options it can be use to add or change the
64 pass phrase. These options can only be used with PEM format output
65 files.
66 -text
68 Prints out the public, private key components and parameters.
69 -noout
71 This option prevents output of the encoded version of the key.
72 -modulus
74 This option prints out the value of the public key component of the
75 key.
76 -pubin
78 By default, a private key is read from the input file. With this
79 option a public key is read instead.
80 -pubout
82 By default a private key is output. With this option a public key
83 will be output instead. This option is automatically set if the
84 input is a public key.
85 -conv_form
87 This specifies how the points on the elliptic curve are converted
88 into octet strings. Possible values are: compressed (the default
89 value), uncompressed and hybrid. For more information regarding the
90 point conversion forms please read the X9.62 standard. Note Due to
91 patent issues the compressed option is disabled by default for
92 binary curves and can be enabled by defining the preprocessor macro
93 OPENSSL_EC_BIN_PT_COMP at compile time.
94 -param_enc arg
96 This specifies how the elliptic curve parameters are encoded.
97 Possible value are: named_curve, i.e. the ec parameters are
98 specified by an OID, or explicit where the ec parameters are
99 explicitly given (see RFC 3279 for the definition of the EC
100 parameters structures). The default value is named_curve. Note the
101 implicitlyCA alternative, as specified in RFC 3279, is currently
102 not implemented in OpenSSL.
103 -no_public
105 This option omits the public key components from the private key
106 output.
107 -check
109 This option checks the consistency of an EC private or public key.
110 -engine id
112 Specifying an engine (by its unique id string) will cause ec to
113 attempt to obtain a functional reference to the specified engine,
114 thus initialising it if needed. The engine will then be set as the
115 default for all available algorithms.
116
118 The PEM private key format uses the header and footer lines:
119 -----BEGIN EC PRIVATE KEY-----
121 -----END EC PRIVATE KEY-----
122 The PEM public key format uses the header and footer lines:
124 -----BEGIN PUBLIC KEY-----
126 -----END PUBLIC KEY-----
127
129 To encrypt a private key using triple DES:
130 openssl ec -in key.pem -des3 -out keyout.pem
132 To convert a private key from PEM to DER format:
134 openssl ec -in key.pem -outform DER -out keyout.der
136 To print out the components of a private key to standard output:
138 openssl ec -in key.pem -text -noout
140 To just output the public part of a private key:
142 openssl ec -in key.pem -pubout -out pubkey.pem
144 To change the parameters encoding to explicit:
146 openssl ec -in key.pem -param_enc explicit -out keyout.pem
148 To change the point conversion form to compressed:
150 openssl ec -in key.pem -conv_form compressed -out keyout.pem
152
154 ecparam(1), dsa(1), rsa(1)
155
157 Copyright 2003-2017 The OpenSSL Project Authors. All Rights Reserved.
158 Licensed under the OpenSSL license (the "License"). You may not use
160 this file except in compliance with the License. You can obtain a copy
161 in the file LICENSE in the source distribution or at
162 <https://www.openssl.org/source/license.html>.
1631.1.1 2018-09-11 EC(1)