31 The B<ec> command processes EC keys. They can be converted between various
32 forms and their components printed out. B<Note> OpenSSL uses the
33 private key format specified in 'SEC 1: Elliptic Curve Cryptography'
34 (http://www.secg.org/). To convert a OpenSSL EC private key into the
35 PKCS#8 private key format use the B<pkcs8> command.
37 =head1 COMMAND OPTIONS
41 =item B<-inform DER|PEM>
43 This specifies the input format. The B<DER> option with a private key uses
44 an ASN.1 DER encoded SEC1 private key. When used with a public key it
45 uses the SubjectPublicKeyInfo structure as specified in RFC 3280.
46 The B<PEM> form is the default format: it consists of the B<DER> format base64
47 encoded with additional header and footer lines. In the case of a private key
48 PKCS#8 format is also accepted.
50 =item B<-outform DER|PEM>
52 This specifies the output format, the options have the same meaning as the
57 This specifies the input filename to read a key from or standard input if this
58 option is not specified. If the key is encrypted a pass phrase will be
63 the input file password source. For more information about the format of B<arg>
64 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
66 =item B<-out filename>
68 This specifies the output filename to write a key to or standard output by
69 is not specified. If any encryption options are set then a pass phrase will be
70 prompted for. The output filename should B<not> be the same as the input
75 the output file password source. For more information about the format of B<arg>
76 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
78 =item B<-des|-des3|-idea>
80 These options encrypt the private key with the DES, triple DES, IDEA or
81 any other cipher supported by OpenSSL before outputting it. A pass phrase is
83 If none of these options is specified the key is written in plain text. This
84 means that using the B<ec> utility to read in an encrypted key with no
85 encryption option can be used to remove the pass phrase from a key, or by
86 setting the encryption options it can be use to add or change the pass phrase.
87 These options can only be used with PEM format output files.
91 prints out the public, private key components and parameters.
95 this option prevents output of the encoded version of the key.
99 this option prints out the value of the public key component of the key.
103 by default a private key is read from the input file: with this option a
104 public key is read instead.
108 by default a private key is output. With this option a public
109 key will be output instead. This option is automatically set if the input is
114 This specifies how the points on the elliptic curve are converted
115 into octet strings. Possible values are: B<compressed> (the default
116 value), B<uncompressed> and B<hybrid>. For more information regarding
117 the point conversion forms please read the X9.62 standard.
118 B<Note> Due to patent issues the B<compressed> option is disabled
119 by default for binary curves and can be enabled by defining
120 the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time.
122 =item B<-param_enc arg>
124 This specifies how the elliptic curve parameters are encoded.
125 Possible value are: B<named_curve>, i.e. the ec parameters are
126 specified by a OID, or B<explicit> where the ec parameters are
127 explicitly given (see RFC 3279 for the definition of the
128 EC parameters structures). The default value is B<named_curve>.
129 B<Note> the B<implicitlyCA> alternative ,as specified in RFC 3279,
130 is currently not implemented in OpenSSL.
134 specifying an engine (by its unique B<id> string) will cause B<ec>
135 to attempt to obtain a functional reference to the specified engine,
136 thus initialising it if needed. The engine will then be set as the default
137 for all available algorithms.
143 The PEM private key format uses the header and footer lines:
145 -----BEGIN EC PRIVATE KEY-----
146 -----END EC PRIVATE KEY-----
148 The PEM public key format uses the header and footer lines:
150 -----BEGIN PUBLIC KEY-----
151 -----END PUBLIC KEY-----
155 To encrypt a private key using triple DES:
157 openssl ec -in key.pem -des3 -out keyout.pem
159 To convert a private key from PEM to DER format:
161 openssl ec -in key.pem -outform DER -out keyout.der
163 To print out the components of a private key to standard output:
165 openssl ec -in key.pem -text -noout
167 To just output the public part of a private key:
169 openssl ec -in key.pem -pubout -out pubkey.pem
171 To change the parameters encoding to B<explicit>:
173 openssl ec -in key.pem -param_enc explicit -out keyout.pem
175 To change the point conversion form to B<compressed>:
177 openssl ec -in key.pem -conv_form compressed -out keyout.pem
181 L<ecparam(1)|ecparam(1)>, L<dsa(1)|dsa(1)>, L<rsa(1)|rsa(1)>
185 The ec command was first introduced in OpenSSL 0.9.8.
189 Nils Larsch for the OpenSSL project (http://www.openssl.org).