6 rsa - RSA key processing tool
11 [B<-inform PEM|NET|DER>]
12 [B<-outform PEM|NET|DER>]
28 [B<-RSAPublicKey_out>]
33 The B<rsa> command processes RSA keys. They can be converted between various
34 forms and their components printed out. B<Note> this command uses the
35 traditional SSLeay compatible format for private key encryption: newer
36 applications should use the more secure PKCS#8 format using the B<pkcs8>
39 =head1 COMMAND OPTIONS
43 =item B<-inform DER|NET|PEM>
45 This specifies the input format. The B<DER> option uses an ASN1 DER encoded
46 form compatible with the PKCS#1 RSAPrivateKey or SubjectPublicKeyInfo format.
47 The B<PEM> form is the default format: it consists of the B<DER> format base64
48 encoded with additional header and footer lines. On input PKCS#8 format private
49 keys are also accepted. The B<NET> form is a format is described in the B<NOTES>
52 =item B<-outform DER|NET|PEM>
54 This specifies the output format, the options have the same meaning as the
59 This specifies the input filename to read a key from or standard input if this
60 option is not specified. If the key is encrypted a pass phrase will be
65 the input file password source. For more information about the format of B<arg>
66 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
68 =item B<-out filename>
70 This specifies the output filename to write a key to or standard output if this
71 option is not specified. If any encryption options are set then a pass phrase
72 will be prompted for. The output filename should B<not> be the same as the input
75 =item B<-passout password>
77 the output file password source. For more information about the format of B<arg>
78 see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)|openssl(1)>.
82 use the modified NET algorithm used with some versions of Microsoft IIS and SGC
85 =item B<-des|-des3|-idea>
87 These options encrypt the private key with the DES, triple DES, or the
88 IDEA ciphers respectively before outputting it. A pass phrase is prompted for.
89 If none of these options is specified the key is written in plain text. This
90 means that using the B<rsa> utility to read in an encrypted key with no
91 encryption option can be used to remove the pass phrase from a key, or by
92 setting the encryption options it can be use to add or change the pass phrase.
93 These options can only be used with PEM format output files.
97 prints out the various public or private key components in
98 plain text in addition to the encoded version.
102 this option prevents output of the encoded version of the key.
106 this option prints out the value of the modulus of the key.
110 this option checks the consistency of an RSA private key.
114 by default a private key is read from the input file: with this
115 option a public key is read instead.
119 by default a private key is output: with this option a public
120 key will be output instead. This option is automatically set if
121 the input is a public key.
123 =item B<-RSAPublicKey_in>, B<-RSAPublicKey_out>
125 like B<-pubin> and B<-pubout> except B<RSAPublicKey> format is used instead.
129 specifying an engine (by its unique B<id> string) will cause B<rsa>
130 to attempt to obtain a functional reference to the specified engine,
131 thus initialising it if needed. The engine will then be set as the default
132 for all available algorithms.
138 The PEM private key format uses the header and footer lines:
140 -----BEGIN RSA PRIVATE KEY-----
141 -----END RSA PRIVATE KEY-----
143 The PEM public key format uses the header and footer lines:
145 -----BEGIN PUBLIC KEY-----
146 -----END PUBLIC KEY-----
148 The PEM B<RSAPublicKey> format uses the header and footer lines:
150 -----BEGIN RSA PUBLIC KEY-----
151 -----END RSA PUBLIC KEY-----
153 The B<NET> form is a format compatible with older Netscape servers
154 and Microsoft IIS .key files, this uses unsalted RC4 for its encryption.
155 It is not very secure and so should only be used when necessary.
157 Some newer version of IIS have additional data in the exported .key
158 files. To use these with the utility, view the file with a binary editor
159 and look for the string "private-key", then trace back to the byte
160 sequence 0x30, 0x82 (this is an ASN1 SEQUENCE). Copy all the data
161 from this point onwards to another file and use that as the input
162 to the B<rsa> utility with the B<-inform NET> option. If you get
163 an error after entering the password try the B<-sgckey> option.
167 To remove the pass phrase on an RSA private key:
169 openssl rsa -in key.pem -out keyout.pem
171 To encrypt a private key using triple DES:
173 openssl rsa -in key.pem -des3 -out keyout.pem
175 To convert a private key from PEM to DER format:
177 openssl rsa -in key.pem -outform DER -out keyout.der
179 To print out the components of a private key to standard output:
181 openssl rsa -in key.pem -text -noout
183 To just output the public part of a private key:
185 openssl rsa -in key.pem -pubout -out pubkey.pem
187 Output the public part of a private key in B<RSAPublicKey> format:
189 openssl rsa -in key.pem -RSAPublicKey_out -out pubkey.pem
193 The command line password arguments don't currently work with
196 There should be an option that automatically handles .key files,
197 without having to manually edit them.
201 L<pkcs8(1)|pkcs8(1)>, L<dsa(1)|dsa(1)>, L<genrsa(1)|genrsa(1)>,
202 L<gendsa(1)|gendsa(1)>