rsa.pod revision 279265 
1
2=pod
3
4=head1 NAME
5
6rsa - RSA key processing tool
7
8=head1 SYNOPSIS
9
10B<openssl> B<rsa>
11[B<-inform PEM|NET|DER>]
12[B<-outform PEM|NET|DER>]
13[B<-in filename>]
14[B<-passin arg>]
15[B<-out filename>]
16[B<-passout arg>]
17[B<-sgckey>]
18[B<-aes128>]
19[B<-aes192>]
20[B<-aes256>]
21[B<-camellia128>]
22[B<-camellia192>]
23[B<-camellia256>]
24[B<-des>]
25[B<-des3>]
26[B<-idea>]
27[B<-text>]
28[B<-noout>]
29[B<-modulus>]
30[B<-check>]
31[B<-pubin>]
32[B<-pubout>]
33[B<-engine id>]
34
35=head1 DESCRIPTION
36
37The B<rsa> command processes RSA keys. They can be converted between various
38forms and their components printed out. B<Note> this command uses the
39traditional SSLeay compatible format for private key encryption: newer
40applications should use the more secure PKCS#8 format using the B<pkcs8>
41utility.
42
43=head1 COMMAND OPTIONS
44
45=over 4
46
47=item B<-inform DER|NET|PEM>
48
49This specifies the input format. The B<DER> option uses an ASN1 DER encoded
50form compatible with the PKCS#1 RSAPrivateKey or SubjectPublicKeyInfo format.
51The B<PEM> form is the default format: it consists of the B<DER> format base64
52encoded with additional header and footer lines. On input PKCS#8 format private
53keys are also accepted. The B<NET> form is a format is described in the B<NOTES>
54section.
55
56=item B<-outform DER|NET|PEM>
57
58This specifies the output format, the options have the same meaning as the 
59B<-inform> option.
60
61=item B<-in filename>
62
63This specifies the input filename to read a key from or standard input if this
64option is not specified. If the key is encrypted a pass phrase will be
65prompted for.
66
67=item B<-passin arg>
68
69the input file password source. For more information about the format of B<arg>
70see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
71
72=item B<-out filename>
73
74This specifies the output filename to write a key to or standard output if this
75option is not specified. If any encryption options are set then a pass phrase
76will be prompted for. The output filename should B<not> be the same as the input
77filename.
78
79=item B<-passout password>
80
81the output file password source. For more information about the format of B<arg>
82see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
83
84=item B<-sgckey>
85
86use the modified NET algorithm used with some versions of Microsoft IIS and SGC
87keys.
88
89=item B<-aes128|-aes192|-aes256|-camellia128|-camellia192|-camellia256|-des|-des3|-idea>
90
91These options encrypt the private key with the specified
92cipher before outputting it. A pass phrase is prompted for.
93If none of these options is specified the key is written in plain text. This
94means that using the B<rsa> utility to read in an encrypted key with no
95encryption option can be used to remove the pass phrase from a key, or by
96setting the encryption options it can be use to add or change the pass phrase.
97These options can only be used with PEM format output files.
98
99=item B<-text>
100
101prints out the various public or private key components in
102plain text in addition to the encoded version. 
103
104=item B<-noout>
105
106this option prevents output of the encoded version of the key.
107
108=item B<-modulus>
109
110this option prints out the value of the modulus of the key.
111
112=item B<-check>
113
114this option checks the consistency of an RSA private key.
115
116=item B<-pubin>
117
118by default a private key is read from the input file: with this
119option a public key is read instead.
120
121=item B<-pubout>
122
123by default a private key is output: with this option a public
124key will be output instead. This option is automatically set if
125the input is a public key.
126
127=item B<-engine id>
128
129specifying an engine (by it's unique B<id> string) will cause B<req>
130to attempt to obtain a functional reference to the specified engine,
131thus initialising it if needed. The engine will then be set as the default
132for all available algorithms.
133
134=back
135
136=head1 NOTES
137
138The PEM private key format uses the header and footer lines:
139
140 -----BEGIN RSA PRIVATE KEY-----
141 -----END RSA PRIVATE KEY-----
142
143The PEM public key format uses the header and footer lines:
144
145 -----BEGIN PUBLIC KEY-----
146 -----END PUBLIC KEY-----
147
148The B<NET> form is a format compatible with older Netscape servers
149and Microsoft IIS .key files, this uses unsalted RC4 for its encryption.
150It is not very secure and so should only be used when necessary.
151
152Some newer version of IIS have additional data in the exported .key
153files. To use these with the utility, view the file with a binary editor
154and look for the string "private-key", then trace back to the byte
155sequence 0x30, 0x82 (this is an ASN1 SEQUENCE). Copy all the data
156from this point onwards to another file and use that as the input
157to the B<rsa> utility with the B<-inform NET> option. If you get
158an error after entering the password try the B<-sgckey> option.
159
160=head1 EXAMPLES
161
162To remove the pass phrase on an RSA private key:
163
164 openssl rsa -in key.pem -out keyout.pem
165
166To encrypt a private key using triple DES:
167
168 openssl rsa -in key.pem -des3 -out keyout.pem
169
170To convert a private key from PEM to DER format: 
171
172 openssl rsa -in key.pem -outform DER -out keyout.der
173
174To print out the components of a private key to standard output:
175
176 openssl rsa -in key.pem -text -noout
177
178To just output the public part of a private key:
179
180 openssl rsa -in key.pem -pubout -out pubkey.pem
181
182=head1 BUGS
183
184The command line password arguments don't currently work with
185B<NET> format.
186
187There should be an option that automatically handles .key files,
188without having to manually edit them.
189
190=head1 SEE ALSO
191
192L<pkcs8(1)|pkcs8(1)>, L<dsa(1)|dsa(1)>, L<genrsa(1)|genrsa(1)>,
193L<gendsa(1)|gendsa(1)> 
194
195=cut
196