6 rsa - RSA key processing tool
11 [B<-inform PEM|NET|DER>]
12 [B<-outform PEM|NET|DER>]
31 The B<rsa> command processes RSA keys. They can be converted between various
32 forms and their components printed out. B<Note> this command uses the
33 traditional SSLeay compatible format for private key encryption: newer
34 applications should use the more secure PKCS#8 format using the B<pkcs8>
37 =head1 COMMAND OPTIONS
41 =item B<-inform DER|NET|PEM>
43 This specifies the input format. The B<DER> option uses an ASN1 DER encoded
44 form compatible with the PKCS#1 RSAPrivateKey or SubjectPublicKeyInfo format.
45 The B<PEM> form is the default format: it consists of the B<DER> format base64
46 encoded with additional header and footer lines. On input PKCS#8 format private
47 keys are also accepted. The B<NET> form is a format is described in the B<NOTES>
50 =item B<-outform DER|NET|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 if this
69 option is not specified. If any encryption options are set then a pass phrase
70 will be prompted for. The output filename should B<not> be the same as the input
73 =item B<-passout password>
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)>.
80 use the modified NET algorithm used with some versions of Microsoft IIS and SGC
83 =item B<-des|-des3|-idea>
85 These options encrypt the private key with the DES, triple DES, or the
86 IDEA ciphers respectively before outputting it. A pass phrase is prompted for.
87 If none of these options is specified the key is written in plain text. This
88 means that using the B<rsa> utility to read in an encrypted key with no
89 encryption option can be used to remove the pass phrase from a key, or by
90 setting the encryption options it can be use to add or change the pass phrase.
91 These options can only be used with PEM format output files.
95 prints out the various public or private key components in
96 plain text in addition to the encoded version.
100 this option prevents output of the encoded version of the key.
104 this option prints out the value of the modulus of the key.
108 this option checks the consistency of an RSA private key.
112 by default a private key is read from the input file: with this
113 option a public key is read instead.
117 by default a private key is output: with this option a public
118 key will be output instead. This option is automatically set if
119 the input is a public key.
123 specifying an engine (by its unique B<id> string) will cause B<rsa>
124 to attempt to obtain a functional reference to the specified engine,
125 thus initialising it if needed. The engine will then be set as the default
126 for all available algorithms.
132 The PEM private key format uses the header and footer lines:
134 -----BEGIN RSA PRIVATE KEY-----
135 -----END RSA PRIVATE KEY-----
137 The PEM public key format uses the header and footer lines:
139 -----BEGIN PUBLIC KEY-----
140 -----END PUBLIC KEY-----
142 The B<NET> form is a format compatible with older Netscape servers
143 and Microsoft IIS .key files, this uses unsalted RC4 for its encryption.
144 It is not very secure and so should only be used when necessary.
146 Some newer version of IIS have additional data in the exported .key
147 files. To use these with the utility, view the file with a binary editor
148 and look for the string "private-key", then trace back to the byte
149 sequence 0x30, 0x82 (this is an ASN1 SEQUENCE). Copy all the data
150 from this point onwards to another file and use that as the input
151 to the B<rsa> utility with the B<-inform NET> option. If you get
152 an error after entering the password try the B<-sgckey> option.
156 To remove the pass phrase on an RSA private key:
158 openssl rsa -in key.pem -out keyout.pem
160 To encrypt a private key using triple DES:
162 openssl rsa -in key.pem -des3 -out keyout.pem
164 To convert a private key from PEM to DER format:
166 openssl rsa -in key.pem -outform DER -out keyout.der
168 To print out the components of a private key to standard output:
170 openssl rsa -in key.pem -text -noout
172 To just output the public part of a private key:
174 openssl rsa -in key.pem -pubout -out pubkey.pem
178 The command line password arguments don't currently work with
181 There should be an option that automatically handles .key files,
182 without having to manually edit them.
186 L<pkcs8(1)|pkcs8(1)>, L<dsa(1)|dsa(1)>, L<genrsa(1)|genrsa(1)>,
187 L<gendsa(1)|gendsa(1)>