rsa



RSA(1)                              OpenSSL                             RSA(1)




NAME

       rsa - RSA key processing tool


SYNOPSIS

       openssl rsa [-inform PEMβ”β”‚NETβ”β”‚DER] [-outform PEMβ”β”‚NETβ”β”‚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 vari-
       ous 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 DERβ”β”‚NETβ”β”‚PEM
           This specifies the input format. The DER option uses an ASN1 DER
           encoded form compatible with the PKCS#1 RSAPrivateKey or Subject-
           PublicKeyInfo format.  The PEM form is the default format: it con-
           sists 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 sec-
           tion.

       -outform DERβ”β”‚NETβ”β”‚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 for-
           mat 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 file-
           name 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.

       -desβ”β”‚-des3β”β”‚-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 it’s unique id string) will cause req 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 edi-
       tor 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 for-
       mat.

       There should be an option that automatically handles .key files, with-
       out having to manually edit them.


SEE ALSO

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



0.9.7f                            2003-01-30                            RSA(1)

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