5 ecparam - EC parameter manipulation and generation
30 This command is used to manipulate or generate EC parameter files.
38 Print out a usage message.
40 =item B<-inform DER|PEM>
42 This specifies the input format. The B<DER> option uses an ASN.1 DER encoded
43 form compatible with RFC 3279 EcpkParameters. The PEM form is the default
44 format: it consists of the B<DER> format base64 encoded with additional
45 header and footer lines.
47 =item B<-outform DER|PEM>
49 This specifies the output format, the options have the same meaning as the
54 This specifies the input filename to read parameters from or standard input if
55 this option is not specified.
57 =item B<-out filename>
59 This specifies the output filename parameters to. Standard output is used
60 if this option is not present. The output filename should B<not> be the same
61 as the input filename.
65 This option inhibits the output of the encoded version of the parameters.
69 This option prints out the EC parameters in human readable form.
73 This option converts the EC parameters into C code. The parameters can then
74 be loaded by calling the get_ec_group_XXX() function.
78 Validate the elliptic curve parameters.
82 Use the EC parameters with the specified 'short' name. Use B<-list_curves>
83 to get a list of all currently implemented EC parameters.
87 If this options is specified B<ecparam> will print out a list of all
88 currently implemented EC parameters names and exit.
92 This specifies how the points on the elliptic curve are converted
93 into octet strings. Possible values are: B<compressed> (the default
94 value), B<uncompressed> and B<hybrid>. For more information regarding
95 the point conversion forms please read the X9.62 standard.
96 B<Note> Due to patent issues the B<compressed> option is disabled
97 by default for binary curves and can be enabled by defining
98 the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time.
100 =item B<-param_enc arg>
102 This specifies how the elliptic curve parameters are encoded.
103 Possible value are: B<named_curve>, i.e. the ec parameters are
104 specified by an OID, or B<explicit> where the ec parameters are
105 explicitly given (see RFC 3279 for the definition of the
106 EC parameters structures). The default value is B<named_curve>.
107 B<Note> the B<implicitlyCA> alternative, as specified in RFC 3279,
108 is currently not implemented in OpenSSL.
112 This option inhibits that the 'seed' for the parameter generation
113 is included in the ECParameters structure (see RFC 3279).
117 This option will generate an EC private key using the specified parameters.
119 =item B<-rand file(s)>
121 a file or files containing random data used to seed the random number
122 generator, or an EGD socket (see L<RAND_egd(3)>).
123 Multiple files can be specified separated by an OS-dependent character.
124 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
129 specifying an engine (by its unique B<id> string) will cause B<ecparam>
130 to attempt to obtain a functional reference to the specified engine,
131 thus initialising it if needed. The engine will then be set as the default
132 for all available algorithms.
138 PEM format EC parameters use the header and footer lines:
140 -----BEGIN EC PARAMETERS-----
141 -----END EC PARAMETERS-----
143 OpenSSL is currently not able to generate new groups and therefore
144 B<ecparam> can only create EC parameters from known (named) curves.
148 To create EC parameters with the group 'prime192v1':
150 openssl ecparam -out ec_param.pem -name prime192v1
152 To create EC parameters with explicit parameters:
154 openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicit
156 To validate given EC parameters:
158 openssl ecparam -in ec_param.pem -check
160 To create EC parameters and a private key:
162 openssl ecparam -out ec_key.pem -name prime192v1 -genkey
164 To change the point encoding to 'compressed':
166 openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressed
168 To print out the EC parameters to standard output:
170 openssl ecparam -in ec_param.pem -noout -text
174 L<ec(1)>, L<dsaparam(1)>
178 Copyright 2003-2016 The OpenSSL Project Authors. All Rights Reserved.
180 Licensed under the OpenSSL license (the "License"). You may not use
181 this file except in compliance with the License. You can obtain a copy
182 in the file LICENSE in the source distribution or at
183 L<https://www.openssl.org/source/license.html>.