6 rsa - RSA key processing tool
11 [B<-inform PEM|NET|DER>]
12 [B<-outform PEM|NET|DER>]
30 The B<rsa> command processes RSA keys. They can be converted between various
31 forms and their components printed out. B<Note> this command uses the
32 traditional SSLeay compatible format for private key encryption: newer
33 applications should use the more secure PKCS#8 format using the B<pkcs8>
36 =head1 COMMAND OPTIONS
40 =item B<-inform DER|NET|PEM>
42 This specifies the input format. The B<DER> option uses an ASN1 DER encoded
43 form compatible with the PKCS#1 RSAPrivateKey or SubjectPublicKeyInfo format.
44 The B<PEM> form is the default format: it consists of the B<DER> format base64
45 encoded with additional header and footer lines. On input PKCS#8 format private
46 keys are also accepted. The B<NET> form is a format is described in the B<NOTES>
49 =item B<-outform DER|NET|PEM>
51 This specifies the output format, the options have the same meaning as the
56 This specifies the input filename to read a key from or standard input if this
57 option is not specified. If the key is encrypted a pass phrase will be
62 the input file password source. For more information about the format of B<arg>
63 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
65 =item B<-out filename>
67 This specifies the output filename to write a key to or standard output if this
68 option is not specified. If any encryption options are set then a pass phrase
69 will be prompted for. The output filename should B<not> be the same as the input
72 =item B<-passout password>
74 the output file password source. For more information about the format of B<arg>
75 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
79 use the modified NET algorithm used with some versions of Microsoft IIS and SGC
82 =item B<-des|-des3|-idea>
84 These options encrypt the private key with the DES, triple DES, or the
85 IDEA ciphers respectively before outputting it. A pass phrase is prompted for.
86 If none of these options is specified the key is written in plain text. This
87 means that using the B<rsa> utility to read in an encrypted key with no
88 encryption option can be used to remove the pass phrase from a key, or by
89 setting the encryption options it can be use to add or change the pass phrase.
90 These options can only be used with PEM format output files.
94 prints out the various public or private key components in
95 plain text in addition to the encoded version.
99 this option prevents output of the encoded version of the key.
103 this option prints out the value of the modulus of the key.
107 this option checks the consistency of an RSA private key.
111 by default a private key is read from the input file: with this
112 option a public key is read instead.
116 by default a private key is output: with this option a public
117 key will be output instead. This option is automatically set if
118 the input is a public key.
124 The PEM private key format uses the header and footer lines:
126 -----BEGIN RSA PRIVATE KEY-----
127 -----END RSA PRIVATE KEY-----
129 The PEM public key format uses the header and footer lines:
131 -----BEGIN PUBLIC KEY-----
132 -----END PUBLIC KEY-----
134 The B<NET> form is a format compatible with older Netscape servers
135 and Microsoft IIS .key files, this uses unsalted RC4 for its encryption.
136 It is not very secure and so should only be used when necessary.
138 Some newer version of IIS have additional data in the exported .key
139 files. To use thse with the utility view the file with a binary editor
140 and look for the string "private-key", then trace back to the byte
141 sequence 0x30, 0x82 (this is an ASN1 SEQUENCE). Copy all the data
142 from this point onwards to another file and use that as the input
143 to the B<rsa> utility with the B<-inform NET> option. If you get
144 an error after entering the password try the B<-sgckey> option.
148 To remove the pass phrase on an RSA private key:
150 openssl rsa -in key.pem -out keyout.pem
152 To encrypt a private key using triple DES:
154 openssl rsa -in key.pem -des3 -out keyout.pem
156 To convert a private key from PEM to DER format:
158 openssl rsa -in key.pem -outform DER -out keyout.der
160 To print out the components of a private key to standard output:
162 openssl rsa -in key.pem -text -noout
164 To just output the public part of a private key:
166 openssl rsa -in key.pem -pubout -out pubkey.pem
170 The command line password arguments don't currently work with
173 There should be an option that automatically handles .key files,
174 without having to manually edit them.
178 L<pkcs8(1)|pkcs8(1)>, L<dsa(1)|dsa(1)>, L<genrsa(1)|genrsa(1)>,
179 L<gendsa(1)|gendsa(1)>