ec.pod revision 325337
1=pod 2 3=head1 NAME 4 5openssl-ec, 6ec - EC key processing 7 8=head1 SYNOPSIS 9 10B<openssl> B<ec> 11[B<-inform PEM|DER>] 12[B<-outform PEM|DER>] 13[B<-in filename>] 14[B<-passin arg>] 15[B<-out filename>] 16[B<-passout arg>] 17[B<-des>] 18[B<-des3>] 19[B<-idea>] 20[B<-text>] 21[B<-noout>] 22[B<-param_out>] 23[B<-pubin>] 24[B<-pubout>] 25[B<-conv_form arg>] 26[B<-param_enc arg>] 27[B<-engine id>] 28 29=head1 DESCRIPTION 30 31The B<ec> command processes EC keys. They can be converted between various 32forms and their components printed out. B<Note> OpenSSL uses the 33private key format specified in 'SEC 1: Elliptic Curve Cryptography' 34(http://www.secg.org/). To convert a OpenSSL EC private key into the 35PKCS#8 private key format use the B<pkcs8> command. 36 37=head1 COMMAND OPTIONS 38 39=over 4 40 41=item B<-inform DER|PEM> 42 43This specifies the input format. The B<DER> option with a private key uses 44an ASN.1 DER encoded SEC1 private key. When used with a public key it 45uses the SubjectPublicKeyInfo structure as specified in RFC 3280. 46The B<PEM> form is the default format: it consists of the B<DER> format base64 47encoded with additional header and footer lines. In the case of a private key 48PKCS#8 format is also accepted. 49 50=item B<-outform DER|PEM> 51 52This specifies the output format, the options have the same meaning as the 53B<-inform> option. 54 55=item B<-in filename> 56 57This specifies the input filename to read a key from or standard input if this 58option is not specified. If the key is encrypted a pass phrase will be 59prompted for. 60 61=item B<-passin arg> 62 63the input file password source. For more information about the format of B<arg> 64see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>. 65 66=item B<-out filename> 67 68This specifies the output filename to write a key to or standard output by 69is not specified. If any encryption options are set then a pass phrase will be 70prompted for. The output filename should B<not> be the same as the input 71filename. 72 73=item B<-passout arg> 74 75the output file password source. For more information about the format of B<arg> 76see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>. 77 78=item B<-des|-des3|-idea> 79 80These options encrypt the private key with the DES, triple DES, IDEA or 81any other cipher supported by OpenSSL before outputting it. A pass phrase is 82prompted for. 83If none of these options is specified the key is written in plain text. This 84means that using the B<ec> utility to read in an encrypted key with no 85encryption option can be used to remove the pass phrase from a key, or by 86setting the encryption options it can be use to add or change the pass phrase. 87These options can only be used with PEM format output files. 88 89=item B<-text> 90 91prints out the public, private key components and parameters. 92 93=item B<-noout> 94 95this option prevents output of the encoded version of the key. 96 97=item B<-modulus> 98 99this option prints out the value of the public key component of the key. 100 101=item B<-pubin> 102 103by default a private key is read from the input file: with this option a 104public key is read instead. 105 106=item B<-pubout> 107 108by default a private key is output. With this option a public 109key will be output instead. This option is automatically set if the input is 110a public key. 111 112=item B<-conv_form> 113 114This specifies how the points on the elliptic curve are converted 115into octet strings. Possible values are: B<compressed> (the default 116value), B<uncompressed> and B<hybrid>. For more information regarding 117the point conversion forms please read the X9.62 standard. 118B<Note> Due to patent issues the B<compressed> option is disabled 119by default for binary curves and can be enabled by defining 120the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time. 121 122=item B<-param_enc arg> 123 124This specifies how the elliptic curve parameters are encoded. 125Possible value are: B<named_curve>, i.e. the ec parameters are 126specified by a OID, or B<explicit> where the ec parameters are 127explicitly given (see RFC 3279 for the definition of the 128EC parameters structures). The default value is B<named_curve>. 129B<Note> the B<implicitlyCA> alternative ,as specified in RFC 3279, 130is currently not implemented in OpenSSL. 131 132=item B<-engine id> 133 134specifying an engine (by its unique B<id> string) will cause B<ec> 135to attempt to obtain a functional reference to the specified engine, 136thus initialising it if needed. The engine will then be set as the default 137for all available algorithms. 138 139=back 140 141=head1 NOTES 142 143The PEM private key format uses the header and footer lines: 144 145 -----BEGIN EC PRIVATE KEY----- 146 -----END EC PRIVATE KEY----- 147 148The PEM public key format uses the header and footer lines: 149 150 -----BEGIN PUBLIC KEY----- 151 -----END PUBLIC KEY----- 152 153=head1 EXAMPLES 154 155To encrypt a private key using triple DES: 156 157 openssl ec -in key.pem -des3 -out keyout.pem 158 159To convert a private key from PEM to DER format: 160 161 openssl ec -in key.pem -outform DER -out keyout.der 162 163To print out the components of a private key to standard output: 164 165 openssl ec -in key.pem -text -noout 166 167To just output the public part of a private key: 168 169 openssl ec -in key.pem -pubout -out pubkey.pem 170 171To change the parameters encoding to B<explicit>: 172 173 openssl ec -in key.pem -param_enc explicit -out keyout.pem 174 175To change the point conversion form to B<compressed>: 176 177 openssl ec -in key.pem -conv_form compressed -out keyout.pem 178 179=head1 SEE ALSO 180 181L<ecparam(1)|ecparam(1)>, L<dsa(1)|dsa(1)>, L<rsa(1)|rsa(1)> 182 183=head1 HISTORY 184 185The ec command was first introduced in OpenSSL 0.9.8. 186 187=head1 AUTHOR 188 189Nils Larsch for the OpenSSL project (http://www.openssl.org). 190 191=cut 192