1ECPARAM(1)                          OpenSSL                         ECPARAM(1)
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NAME

6       openssl-ecparam, ecparam - EC parameter manipulation and generation
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SYNOPSIS

9       openssl ecparam [-help] [-inform DER|PEM] [-outform DER|PEM] [-in
10       filename] [-out filename] [-noout] [-text] [-C] [-check] [-name arg]
11       [-list_curves] [-conv_form arg] [-param_enc arg] [-no_seed] [-rand
12       file...]  [-writerand file] [-genkey] [-engine id]
13

DESCRIPTION

15       This command is used to manipulate or generate EC parameter files.
16

OPTIONS

18       -help
19           Print out a usage message.
20
21       -inform DER|PEM
22           This specifies the input format. The DER option uses an ASN.1 DER
23           encoded form compatible with RFC 3279 EcpkParameters. The PEM form
24           is the default format: it consists of the DER format base64 encoded
25           with additional header and footer lines.
26
27       -outform DER|PEM
28           This specifies the output format, the options have the same meaning
29           and default as the -inform option.
30
31       -in filename
32           This specifies the input filename to read parameters from or
33           standard input if this option is not specified.
34
35       -out filename
36           This specifies the output filename parameters to. Standard output
37           is used if this option is not present. The output filename should
38           not be the same as the input filename.
39
40       -noout
41           This option inhibits the output of the encoded version of the
42           parameters.
43
44       -text
45           This option prints out the EC parameters in human readable form.
46
47       -C  This option converts the EC parameters into C code. The parameters
48           can then be loaded by calling the get_ec_group_XXX() function.
49
50       -check
51           Validate the elliptic curve parameters.
52
53       -name arg
54           Use the EC parameters with the specified 'short' name. Use
55           -list_curves to get a list of all currently implemented EC
56           parameters.
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58       -list_curves
59           If this options is specified ecparam will print out a list of all
60           currently implemented EC parameters names and exit.
61
62       -conv_form
63           This specifies how the points on the elliptic curve are converted
64           into octet strings. Possible values are: compressed, uncompressed
65           (the default value) and hybrid. For more information regarding the
66           point conversion forms please read the X9.62 standard.  Note Due to
67           patent issues the compressed option is disabled by default for
68           binary curves and can be enabled by defining the preprocessor macro
69           OPENSSL_EC_BIN_PT_COMP at compile time.
70
71       -param_enc arg
72           This specifies how the elliptic curve parameters are encoded.
73           Possible value are: named_curve, i.e. the ec parameters are
74           specified by an OID, or explicit where the ec parameters are
75           explicitly given (see RFC 3279 for the definition of the EC
76           parameters structures). The default value is named_curve.  Note the
77           implicitlyCA alternative, as specified in RFC 3279, is currently
78           not implemented in OpenSSL.
79
80       -no_seed
81           This option inhibits that the 'seed' for the parameter generation
82           is included in the ECParameters structure (see RFC 3279).
83
84       -genkey
85           This option will generate an EC private key using the specified
86           parameters.
87
88       -rand file...
89           A file or files containing random data used to seed the random
90           number generator.  Multiple files can be specified separated by an
91           OS-dependent character.  The separator is ; for MS-Windows, , for
92           OpenVMS, and : for all others.
93
94       [-writerand file]
95           Writes random data to the specified file upon exit.  This can be
96           used with a subsequent -rand flag.
97
98       -engine id
99           Specifying an engine (by its unique id string) will cause ecparam
100           to attempt to obtain a functional reference to the specified
101           engine, thus initialising it if needed. The engine will then be set
102           as the default for all available algorithms.
103

NOTES

105       PEM format EC parameters use the header and footer lines:
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107        -----BEGIN EC PARAMETERS-----
108        -----END EC PARAMETERS-----
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110       OpenSSL is currently not able to generate new groups and therefore
111       ecparam can only create EC parameters from known (named) curves.
112

EXAMPLES

114       To create EC parameters with the group 'prime192v1':
115
116         openssl ecparam -out ec_param.pem -name prime192v1
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118       To create EC parameters with explicit parameters:
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120         openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicit
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122       To validate given EC parameters:
123
124         openssl ecparam -in ec_param.pem -check
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126       To create EC parameters and a private key:
127
128         openssl ecparam -out ec_key.pem -name prime192v1 -genkey
129
130       To change the point encoding to 'compressed':
131
132         openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressed
133
134       To print out the EC parameters to standard output:
135
136         openssl ecparam -in ec_param.pem -noout -text
137

SEE ALSO

139       ec(1), dsaparam(1)
140

142       Copyright 2003-2018 The OpenSSL Project Authors. All Rights Reserved.
143
144       Licensed under the OpenSSL license (the "License").  You may not use
145       this file except in compliance with the License.  You can obtain a copy
146       in the file LICENSE in the source distribution or at
147       <https://www.openssl.org/source/license.html>.
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1511.1.1k                            2021-03-26                        ECPARAM(1)
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