ec.pod revision 279264 
1=pod
2
3=head1 NAME
4
5ec - EC key processing
6
7=head1 SYNOPSIS
8
9B<openssl> B<ec>
10[B<-inform PEM|DER>]
11[B<-outform PEM|DER>]
12[B<-in filename>]
13[B<-passin arg>]
14[B<-out filename>]
15[B<-passout arg>]
16[B<-des>]
17[B<-des3>]
18[B<-idea>]
19[B<-text>]
20[B<-noout>]
21[B<-param_out>]
22[B<-pubin>]
23[B<-pubout>]
24[B<-conv_form arg>]
25[B<-param_enc arg>]
26[B<-engine id>]
27
28=head1 DESCRIPTION
29
30The B<ec> command processes EC keys. They can be converted between various
31forms and their components printed out. B<Note> OpenSSL uses the 
32private key format specified in 'SEC 1: Elliptic Curve Cryptography'
33(http://www.secg.org/). To convert a OpenSSL EC private key into the
34PKCS#8 private key format use the B<pkcs8> command.
35
36=head1 COMMAND OPTIONS
37
38=over 4
39
40=item B<-inform DER|PEM>
41
42This specifies the input format. The B<DER> option with a private key uses
43an ASN.1 DER encoded SEC1 private key. When used with a public key it
44uses the SubjectPublicKeyInfo structure as specified in RFC 3280.
45The B<PEM> form is the default format: it consists of the B<DER> format base64
46encoded with additional header and footer lines. In the case of a private key
47PKCS#8 format is also accepted.
48
49=item B<-outform DER|PEM>
50
51This specifies the output format, the options have the same meaning as the 
52B<-inform> option.
53
54=item B<-in filename>
55
56This specifies the input filename to read a key from or standard input if this
57option is not specified. If the key is encrypted a pass phrase will be
58prompted for.
59
60=item B<-passin arg>
61
62the input file password source. For more information about the format of B<arg>
63see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
64
65=item B<-out filename>
66
67This specifies the output filename to write a key to or standard output by
68is not specified. If any encryption options are set then a pass phrase will be
69prompted for. The output filename should B<not> be the same as the input
70filename.
71
72=item B<-passout arg>
73
74the output file password source. For more information about the format of B<arg>
75see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
76
77=item B<-des|-des3|-idea>
78
79These options encrypt the private key with the DES, triple DES, IDEA or 
80any other cipher supported by OpenSSL before outputting it. A pass phrase is
81prompted for.
82If none of these options is specified the key is written in plain text. This
83means that using the B<ec> utility to read in an encrypted key with no
84encryption option can be used to remove the pass phrase from a key, or by
85setting the encryption options it can be use to add or change the pass phrase.
86These options can only be used with PEM format output files.
87
88=item B<-text>
89
90prints out the public, private key components and parameters.
91
92=item B<-noout>
93
94this option prevents output of the encoded version of the key.
95
96=item B<-modulus>
97
98this option prints out the value of the public key component of the key.
99
100=item B<-pubin>
101
102by default a private key is read from the input file: with this option a
103public key is read instead.
104
105=item B<-pubout>
106
107by default a private key is output. With this option a public
108key will be output instead. This option is automatically set if the input is
109a public key.
110
111=item B<-conv_form>
112
113This specifies how the points on the elliptic curve are converted
114into octet strings. Possible values are: B<compressed> (the default
115value), B<uncompressed> and B<hybrid>. For more information regarding
116the point conversion forms please read the X9.62 standard.
117B<Note> Due to patent issues the B<compressed> option is disabled
118by default for binary curves and can be enabled by defining
119the preprocessor macro B<OPENSSL_EC_BIN_PT_COMP> at compile time.
120
121=item B<-param_enc arg>
122
123This specifies how the elliptic curve parameters are encoded.
124Possible value are: B<named_curve>, i.e. the ec parameters are
125specified by a OID, or B<explicit> where the ec parameters are
126explicitly given (see RFC 3279 for the definition of the 
127EC parameters structures). The default value is B<named_curve>.
128B<Note> the B<implicitlyCA> alternative ,as specified in RFC 3279,
129is currently not implemented in OpenSSL.
130
131=item B<-engine id>
132
133specifying an engine (by its unique B<id> string) will cause B<ec>
134to attempt to obtain a functional reference to the specified engine,
135thus initialising it if needed. The engine will then be set as the default
136for all available algorithms.
137
138=back
139
140=head1 NOTES
141
142The PEM private key format uses the header and footer lines:
143
144 -----BEGIN EC PRIVATE KEY-----
145 -----END EC PRIVATE KEY-----
146
147The PEM public key format uses the header and footer lines:
148
149 -----BEGIN PUBLIC KEY-----
150 -----END PUBLIC KEY-----
151
152=head1 EXAMPLES
153
154To encrypt a private key using triple DES:
155
156 openssl ec -in key.pem -des3 -out keyout.pem
157
158To convert a private key from PEM to DER format: 
159
160 openssl ec -in key.pem -outform DER -out keyout.der
161
162To print out the components of a private key to standard output:
163
164 openssl ec -in key.pem -text -noout
165
166To just output the public part of a private key:
167
168 openssl ec -in key.pem -pubout -out pubkey.pem
169
170To change the parameters encoding to B<explicit>:
171
172 openssl ec -in key.pem -param_enc explicit -out keyout.pem
173
174To change the point conversion form to B<compressed>:
175
176 openssl ec -in key.pem -conv_form compressed -out keyout.pem
177
178=head1 SEE ALSO
179
180L<ecparam(1)|ecparam(1)>, L<dsa(1)|dsa(1)>, L<rsa(1)|rsa(1)>
181
182=head1 HISTORY
183
184The ec command was first introduced in OpenSSL 0.9.8.
185
186=head1 AUTHOR
187
188Nils Larsch for the OpenSSL project (http://www.openssl.org).
189
190=cut
191