4 {- join("\n", @autowarntext) -}
10 openssl-ecparam - EC parameter manipulation and generation
16 [B<-inform> B<DER>|B<PEM>]
17 [B<-outform> B<DER>|B<PEM>]
27 [B<-conv_form> I<arg>]
28 [B<-param_enc> I<arg>]
32 {- $OpenSSL::safe::opt_r_synopsis -}
34 =for openssl ifdef engine
38 This command is used to manipulate or generate EC parameter files.
40 OpenSSL is currently not able to generate new groups and therefore
41 this command can only create EC parameters from known (named) curves.
49 Print out a usage message.
51 =item B<-inform> B<DER>|B<PEM>, B<-outform> B<DER>|B<PEM>
53 The input and formats; the default is B<PEM>.
54 See L<openssl(1)/Format Options> 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 This option converts the EC parameters into C code. The parameters can then
80 be loaded by calling the get_ec_group_XXX() function.
84 Validate the elliptic curve parameters.
88 Validate the elliptic name curve parameters by checking if the curve parameters
89 match any built-in curves.
93 Use the EC parameters with the specified 'short' name. Use B<-list_curves>
94 to get a list of all currently implemented EC parameters.
98 Print out a list of all currently implemented EC parameters names and exit.
100 =item B<-conv_form> I<arg>
102 This specifies how the points on the elliptic curve are converted
103 into octet strings. Possible values are: B<compressed>, B<uncompressed> (the
104 default value) and B<hybrid>. For more information regarding
105 the point conversion forms please read the X9.62 standard.
106 B<Note> Due to patent issues the B<compressed> option is disabled
107 by default for binary curves and can be enabled by defining
108 the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time.
110 =item B<-param_enc> I<arg>
112 This specifies how the elliptic curve parameters are encoded.
113 Possible value are: B<named_curve>, i.e. the ec parameters are
114 specified by an OID, or B<explicit> where the ec parameters are
115 explicitly given (see RFC 3279 for the definition of the
116 EC parameters structures). The default value is B<named_curve>.
117 B<Note> the B<implicitlyCA> alternative, as specified in RFC 3279,
118 is currently not implemented in OpenSSL.
122 This option inhibits that the 'seed' for the parameter generation
123 is included in the ECParameters structure (see RFC 3279).
127 This option will generate an EC private key using the specified parameters.
129 =item B<-engine> I<id>
131 Specifying an engine (by its unique I<id> string) will cause B<ecparam>
132 to attempt to obtain a functional reference to the specified engine,
133 thus initialising it if needed. The engine will then be set as the default
134 for all available algorithms.
136 {- $OpenSSL::safe::opt_r_item -}
142 To create EC parameters with the group 'prime192v1':
144 openssl ecparam -out ec_param.pem -name prime192v1
146 To create EC parameters with explicit parameters:
148 openssl ecparam -out ec_param.pem -name prime192v1 -param_enc explicit
150 To validate given EC parameters:
152 openssl ecparam -in ec_param.pem -check
154 To create EC parameters and a private key:
156 openssl ecparam -out ec_key.pem -name prime192v1 -genkey
158 To change the point encoding to 'compressed':
160 openssl ecparam -in ec_in.pem -out ec_out.pem -conv_form compressed
162 To print out the EC parameters to standard output:
164 openssl ecparam -in ec_param.pem -noout -text
170 L<openssl-dsaparam(1)>
174 Copyright 2003-2019 The OpenSSL Project Authors. All Rights Reserved.
176 Licensed under the Apache License 2.0 (the "License"). You may not use
177 this file except in compliance with the License. You can obtain a copy
178 in the file LICENSE in the source distribution or at
179 L<https://www.openssl.org/source/license.html>.