5 ecparam - EC parameter manipulation and generation
31 This command is used to manipulate or generate EC parameter files.
39 Print out a usage message.
41 =item B<-inform DER|PEM>
43 This specifies the input format. The B<DER> option uses an ASN.1 DER encoded
44 form compatible with RFC 3279 EcpkParameters. The PEM form is the default
45 format: it consists of the B<DER> format base64 encoded with additional
46 header and footer lines.
48 =item B<-outform DER|PEM>
50 This specifies the output format, the options have the same meaning and default
51 as the B<-inform> option.
55 This specifies the input filename to read parameters from or standard input if
56 this option is not specified.
58 =item B<-out filename>
60 This specifies the output filename parameters to. Standard output is used
61 if this option is not present. The output filename should B<not> be the same
62 as the input filename.
66 This option inhibits the output of the encoded version of the parameters.
70 This option prints out the EC parameters in human readable form.
74 This option converts the EC parameters into C code. The parameters can then
75 be loaded by calling the get_ec_group_XXX() function.
79 Validate the elliptic curve parameters.
83 Use the EC parameters with the specified 'short' name. Use B<-list_curves>
84 to get a list of all currently implemented EC parameters.
88 If this options is specified B<ecparam> will print out a list of all
89 currently implemented EC parameters names and exit.
93 This specifies how the points on the elliptic curve are converted
94 into octet strings. Possible values are: B<compressed> (the default
95 value), B<uncompressed> and B<hybrid>. For more information regarding
96 the point conversion forms please read the X9.62 standard.
97 B<Note> Due to patent issues the B<compressed> option is disabled
98 by default for binary curves and can be enabled by defining
99 the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time.
101 =item B<-param_enc arg>
103 This specifies how the elliptic curve parameters are encoded.
104 Possible value are: B<named_curve>, i.e. the ec parameters are
105 specified by an OID, or B<explicit> where the ec parameters are
106 explicitly given (see RFC 3279 for the definition of the
107 EC parameters structures). The default value is B<named_curve>.
108 B<Note> the B<implicitlyCA> alternative, as specified in RFC 3279,
109 is currently not implemented in OpenSSL.
113 This option inhibits that the 'seed' for the parameter generation
114 is included in the ECParameters structure (see RFC 3279).
118 This option will generate an EC private key using the specified parameters.
120 =item B<-rand file...>
122 A file or files containing random data used to seed the random number
124 Multiple files can be specified separated by an OS-dependent character.
125 The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
128 =item [B<-writerand file>]
130 Writes random data to the specified I<file> upon exit.
131 This can be used with a subsequent B<-rand> flag.
135 Specifying an engine (by its unique B<id> string) will cause B<ecparam>
136 to attempt to obtain a functional reference to the specified engine,
137 thus initialising it if needed. The engine will then be set as the default
138 for all available algorithms.
144 PEM format EC parameters use the header and footer lines:
146 -----BEGIN EC PARAMETERS-----
147 -----END EC PARAMETERS-----
149 OpenSSL is currently not able to generate new groups and therefore
150 B<ecparam> can only create EC parameters from known (named) curves.
154 To create EC parameters with the group 'prime192v1':
156 openssl ecparam -out ec_param.pem -name prime192v1
158 To create EC parameters with explicit parameters:
160 openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicit
162 To validate given EC parameters:
164 openssl ecparam -in ec_param.pem -check
166 To create EC parameters and a private key:
168 openssl ecparam -out ec_key.pem -name prime192v1 -genkey
170 To change the point encoding to 'compressed':
172 openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressed
174 To print out the EC parameters to standard output:
176 openssl ecparam -in ec_param.pem -noout -text
180 L<ec(1)>, L<dsaparam(1)>
184 Copyright 2003-2017 The OpenSSL Project Authors. All Rights Reserved.
186 Licensed under the OpenSSL license (the "License"). You may not use
187 this file except in compliance with the License. You can obtain a copy
188 in the file LICENSE in the source distribution or at
189 L<https://www.openssl.org/source/license.html>.