RSA(1)                                                       OpenSSL                                                      RSA(1)



NAME
       rsa - RSA key processing tool

SYNOPSIS
       openssl rsa [-inform PEM|NET|DER] [-outform PEM|NET|DER] [-in filename] [-passin arg] [-out filename] [-passout arg]
       [-sgckey] [-des] [-des3] [-idea] [-text] [-noout] [-modulus] [-check] [-pubin] [-pubout] [-engine id]

DESCRIPTION
       The rsa command processes RSA keys. They can be converted between various forms and their components printed out. Note
       this command uses the traditional SSLeay compatible format for private key encryption: newer applications should use the
       more secure PKCS#8 format using the pkcs8 utility.

COMMAND OPTIONS
       -inform DER|NET|PEM
           This specifies the input format. The DER option uses an ASN1 DER encoded form compatible with the PKCS#1
           RSAPrivateKey or SubjectPublicKeyInfo format.  The PEM form is the default format: it consists of the DER format
           base64 encoded with additional header and footer lines. On input PKCS#8 format private keys are also accepted. The
           NET form is a format is described in the NOTES section.

       -outform DER|NET|PEM
           This specifies the output format, the options have the same meaning as the -inform option.

       -in filename
           This specifies the input filename to read a key from or standard input if this option is not specified. If the key is
           encrypted a pass phrase will be prompted for.

       -passin arg
           the input file password source. For more information about the format of arg see the PASS PHRASE ARGUMENTS section in
           openssl(1).

       -out filename
           This specifies the output filename to write a key to or standard output if this option is not specified. If any
           encryption options are set then a pass phrase will be prompted for. The output filename should not be the same as the
           input filename.

       -passout password
           the output file password source. For more information about the format of arg see the PASS PHRASE ARGUMENTS section
           in openssl(1).

       -sgckey
           use the modified NET algorithm used with some versions of Microsoft IIS and SGC keys.

       -des|-des3|-idea
           These options encrypt the private key with the DES, triple DES, or the IDEA ciphers respectively before outputting
           it. A pass phrase is prompted for.  If none of these options is specified the key is written in plain text. This
           means that using the rsa utility to read in an encrypted key with no encryption option can be used to remove the pass
           phrase from a key, or by setting the encryption options it can be use to add or change the pass phrase.  These
           options can only be used with PEM format output files.

       -text
           prints out the various public or private key components in plain text in addition to the encoded version.

       -noout
           this option prevents output of the encoded version of the key.

       -modulus
           this option prints out the value of the modulus of the key.

       -check
           this option checks the consistency of an RSA private key.

       -pubin
           by default a private key is read from the input file: with this option a public key is read instead.

       -pubout
           by default a private key is output: with this option a public key will be output instead. This option is
           automatically set if the input is a public key.

       -engine id
           specifying an engine (by its unique id string) will cause rsa to attempt to obtain a functional reference to the
           specified engine, thus initialising it if needed. The engine will then be set as the default for all available
           algorithms.

NOTES
       The PEM private key format uses the header and footer lines:

        -----BEGIN RSA PRIVATE KEY-----
        -----END RSA PRIVATE KEY-----

       The PEM public key format uses the header and footer lines:

        -----BEGIN PUBLIC KEY-----
        -----END PUBLIC KEY-----

       The NET form is a format compatible with older Netscape servers and Microsoft IIS .key files, this uses unsalted RC4 for
       its encryption.  It is not very secure and so should only be used when necessary.

       Some newer version of IIS have additional data in the exported .key files. To use these with the utility, view the file
       with a binary editor and look for the string "private-key", then trace back to the byte sequence 0x30, 0x82 (this is an
       ASN1 SEQUENCE). Copy all the data from this point onwards to another file and use that as the input to the rsa utility
       with the -inform NET option. If you get an error after entering the password try the -sgckey option.

EXAMPLES
       To remove the pass phrase on an RSA private key:

        openssl rsa -in key.pem -out keyout.pem

       To encrypt a private key using triple DES:

        openssl rsa -in key.pem -des3 -out keyout.pem

       To convert a private key from PEM to DER format:

        openssl rsa -in key.pem -outform DER -out keyout.der

       To print out the components of a private key to standard output:

        openssl rsa -in key.pem -text -noout

       To just output the public part of a private key:

        openssl rsa -in key.pem -pubout -out pubkey.pem

BUGS
       The command line password arguments don't currently work with NET format.

       There should be an option that automatically handles .key files, without having to manually edit them.

SEE ALSO
       pkcs8(1), dsa(1), genrsa(1), gendsa(1)



1.0.0e                                                     2009-04-10                                                     RSA(1)