OpenSL                                          genrsa(1openssl)



NAME
     genrsa - generate an RSA private key

SYNOPSIS
     openssl genrsa [-out filename] [-passout arg] [-des] [-des3]
     [-idea] [-f4] [-3] [-rand file(s)] [-engine id] [numbits]

DESCRIPTION
     The genrsa command generates an RSA private key.

OPTIONS
     -out filename
         the output filename. If this argument is not specified
         then standard output is used.

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

     -des-des3-idea
         These options encrypt the private key with the DES,
         triple DES, or the IDEA ciphers respectively before
         outputting it. If none of these options is specified no
         encryption is used. If encryption is used a pass phrase
         is prompted for if it is not supplied via the -passout
         argument.

     -F4-3
         the public exponent to use, either 65537 or 3. The
         default is 65537.

     -rand file(s)
         a file or files containing random data used to seed the
         random number generator, or an EGD socket (see
         RANDegd(3)).  Multiple files can be specified separated
         by a OS-dependent character.  The separator is ; for
         MS-Windows, , for OpenVMS, and : for all others.

     -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.

     numbits
         the size of the private key to generate in bits. This
         must be the last option specified. The default is 512.

NOTES
     RSA private key generation essentially involves the



OpenSL-0.9.8       Last change: Oct 11 2005                    1






OpenSL                                          genrsa(1openssl)



     generation of two prime numbers. When generating a private
     key various symbols will be output to indicate the progress
     of the generation. A . represents each number which has
     passed an initial sieve test, ] means a number has passed a
     single round of the Miller-Rabin primality test. A newline
     means that the number has passed all the prime tests (the
     actual number depends on the key size).

     Because key generation is a random process the time taken to
     generate a key may vary somewhat.

BUGS
     A quirk of the prime generation algorithm is that it cannot
     generate small primes. Therefore the number of bits should
     not be less that 64. For typical private keys this will not
     matter because for security reasons they will be much larger
     (typically 1024 bits).

SEE ALSO
     gendsa(1)



































OpenSL-0.9.8       Last change: Oct 11 2005                    2