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]


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).

           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.


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-----

       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 thse 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)



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