2 {- OpenSSL::safe::output_do_not_edit_headers(); -}
6 openssl-ecparam - EC parameter manipulation and generation
12 [B<-inform> B<DER>|B<PEM>]
13 [B<-outform> B<DER>|B<PEM>]
22 [B<-conv_form> I<arg>]
23 [B<-param_enc> I<arg>]
26 {- $OpenSSL::safe::opt_engine_synopsis -}{- $OpenSSL::safe::opt_r_synopsis -}
27 {- $OpenSSL::safe::opt_provider_synopsis -}
29 =for openssl ifdef engine
33 This command is used to manipulate or generate EC parameter files.
35 OpenSSL is currently not able to generate new groups and therefore
36 this command can only create EC parameters from known (named) curves.
44 Print out a usage message.
46 =item B<-inform> B<DER>|B<PEM>
48 The EC parameters input format; unspecified by default.
49 See L<openssl-format-options(1)> for details.
51 =item B<-outform> B<DER>|B<PEM>
53 The EC parameters output format; the default is B<PEM>.
54 See L<openssl-format-options(1)> for details.
56 Parameters are encoded as B<EcpkParameters> as specified in IETF RFC 3279.
58 =item B<-in> I<filename>
60 This specifies the input filename to read parameters from or standard input if
61 this option is not specified.
63 =item B<-out> I<filename>
65 This specifies the output filename parameters to. Standard output is used
66 if this option is not present. The output filename should B<not> be the same
67 as the input filename.
71 This option inhibits the output of the encoded version of the parameters.
75 This option prints out the EC parameters in human readable form.
79 Validate the elliptic curve parameters.
83 Validate the elliptic name curve parameters by checking if the curve parameters
84 match any built-in curves.
88 Use the EC parameters with the specified 'short' name. Use B<-list_curves>
89 to get a list of all currently implemented EC parameters.
93 Print out a list of all currently implemented EC parameters names and exit.
95 =item B<-conv_form> I<arg>
97 This specifies how the points on the elliptic curve are converted
98 into octet strings. Possible values are: B<compressed>, B<uncompressed> (the
99 default value) and B<hybrid>. For more information regarding
100 the point conversion forms please read the X9.62 standard.
101 B<Note> Due to patent issues the B<compressed> option is disabled
102 by default for binary curves and can be enabled by defining
103 the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time.
105 =item B<-param_enc> I<arg>
107 This specifies how the elliptic curve parameters are encoded.
108 Possible value are: B<named_curve>, i.e. the ec parameters are
109 specified by an OID, or B<explicit> where the ec parameters are
110 explicitly given (see RFC 3279 for the definition of the
111 EC parameters structures). The default value is B<named_curve>.
112 B<Note> the B<implicitlyCA> alternative, as specified in RFC 3279,
113 is currently not implemented in OpenSSL.
117 This option inhibits that the 'seed' for the parameter generation
118 is included in the ECParameters structure (see RFC 3279).
122 This option will generate an EC private key using the specified parameters.
124 {- $OpenSSL::safe::opt_engine_item -}
126 {- $OpenSSL::safe::opt_r_item -}
128 {- $OpenSSL::safe::opt_provider_item -}
132 The L<openssl-genpkey(1)> and L<openssl-pkeyparam(1)> commands are capable
133 of performing all the operations this command can, as well as supporting
134 other public key types.
138 The documentation for the L<openssl-genpkey(1)> and L<openssl-pkeyparam(1)>
139 commands contains examples equivalent to the ones listed here.
141 To create EC parameters with the group 'prime192v1':
143 openssl ecparam -out ec_param.pem -name prime192v1
145 To create EC parameters with explicit parameters:
147 openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicit
149 To validate given EC parameters:
151 openssl ecparam -in ec_param.pem -check
153 To create EC parameters and a private key:
155 openssl ecparam -out ec_key.pem -name prime192v1 -genkey
157 To change the point encoding to 'compressed':
159 openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressed
161 To print out the EC parameters to standard output:
163 openssl ecparam -in ec_param.pem -noout -text
168 L<openssl-pkeyparam(1)>,
169 L<openssl-genpkey(1)>,
171 L<openssl-dsaparam(1)>
175 The B<-engine> option was deprecated in OpenSSL 3.0.
177 The B<-C> option was removed in OpenSSL 3.0.
181 Copyright 2003-2021 The OpenSSL Project Authors. All Rights Reserved.
183 Licensed under the Apache License 2.0 (the "License"). You may not use
184 this file except in compliance with the License. You can obtain a copy
185 in the file LICENSE in the source distribution or at
186 L<https://www.openssl.org/source/license.html>.