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>]
23 [B<-conv_form> I<arg>]
24 [B<-param_enc> I<arg>]
27 {- $OpenSSL::safe::opt_engine_synopsis -}
28 {- $OpenSSL::safe::opt_r_synopsis -}
29 {- $OpenSSL::safe::opt_provider_synopsis -}
31 =for openssl ifdef engine
35 This command is used to manipulate or generate EC parameter files.
37 OpenSSL is currently not able to generate new groups and therefore
38 this command can only create EC parameters from known (named) curves.
46 Print out a usage message.
48 =item B<-inform> B<DER>|B<PEM>, B<-outform> B<DER>|B<PEM>
50 The input and formats; the default is B<PEM>.
51 See L<openssl(1)/Format Options> for details.
53 Parameters are encoded as B<EcpkParameters> as specified in IETF RFC 3279.
55 =item B<-in> I<filename>
57 This specifies the input filename to read parameters from or standard input if
58 this option is not specified.
60 =item B<-out> I<filename>
62 This specifies the output filename parameters to. Standard output is used
63 if this option is not present. The output filename should B<not> be the same
64 as the input filename.
68 This option inhibits the output of the encoded version of the parameters.
72 This option prints out the EC parameters in human readable form.
76 This option converts the EC parameters into C code. The parameters can then
77 be loaded by calling the get_ec_group_XXX() function.
81 Validate the elliptic curve parameters.
85 Validate the elliptic name curve parameters by checking if the curve parameters
86 match any built-in curves.
90 Use the EC parameters with the specified 'short' name. Use B<-list_curves>
91 to get a list of all currently implemented EC parameters.
95 Print out a list of all currently implemented EC parameters names and exit.
97 =item B<-conv_form> I<arg>
99 This specifies how the points on the elliptic curve are converted
100 into octet strings. Possible values are: B<compressed>, B<uncompressed> (the
101 default value) and B<hybrid>. For more information regarding
102 the point conversion forms please read the X9.62 standard.
103 B<Note> Due to patent issues the B<compressed> option is disabled
104 by default for binary curves and can be enabled by defining
105 the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time.
107 =item B<-param_enc> I<arg>
109 This specifies how the elliptic curve parameters are encoded.
110 Possible value are: B<named_curve>, i.e. the ec parameters are
111 specified by an OID, or B<explicit> where the ec parameters are
112 explicitly given (see RFC 3279 for the definition of the
113 EC parameters structures). The default value is B<named_curve>.
114 B<Note> the B<implicitlyCA> alternative, as specified in RFC 3279,
115 is currently not implemented in OpenSSL.
119 This option inhibits that the 'seed' for the parameter generation
120 is included in the ECParameters structure (see RFC 3279).
124 This option will generate an EC private key using the specified parameters.
126 {- $OpenSSL::safe::opt_engine_item -}
128 {- $OpenSSL::safe::opt_r_item -}
130 {- $OpenSSL::safe::opt_provider_item -}
136 Examples equivalent to these can be found in the documentation for the
137 non-deprecated L<openssl-genpkey(1)> and L<openssl-pkeyparam(1)> commands.
139 To create EC parameters with the group 'prime192v1':
141 openssl ecparam -out ec_param.pem -name prime192v1
143 To create EC parameters with explicit parameters:
145 openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicit
147 To validate given EC parameters:
149 openssl ecparam -in ec_param.pem -check
151 To create EC parameters and a private key:
153 openssl ecparam -out ec_key.pem -name prime192v1 -genkey
155 To change the point encoding to 'compressed':
157 openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressed
159 To print out the EC parameters to standard output:
161 openssl ecparam -in ec_param.pem -noout -text
166 L<openssl-pkeyparam(1)>,
167 L<openssl-genpkey(1)>,
169 L<openssl-dsaparam(1)>
173 Copyright 2003-2020 The OpenSSL Project Authors. All Rights Reserved.
175 Licensed under the Apache License 2.0 (the "License"). You may not use
176 this file except in compliance with the License. You can obtain a copy
177 in the file LICENSE in the source distribution or at
178 L<https://www.openssl.org/source/license.html>.