NAME

       openssl-genrsa - generate an RSA private key

SYNOPSIS

       openssl genrsa [-help] [-out filename] [-passout arg] [-aes128] [-aes192] [-aes256]
       [-aria128] [-aria192] [-aria256] [-camellia128] [-camellia192] [-camellia256] [-des]
       [-des3] [-idea] [-F4] [-f4] [-3] [-primes num] [-verbose] [-traditional] [-rand files]
       [-writerand file] [-engine id] [-provider name] [-provider-path path] [-propquery propq]
       [numbits]

DESCRIPTION

       This command generates an RSA private key.

OPTIONS

       -help
           Print out a usage message.

       -out filename
           Output the key to the specified file. If this argument is not specified then standard
           output is used.

       -passout arg
           The output file password source. For more information about the format see
           openssl-passphrase-options(1).

       -aes128, -aes192, -aes256, -aria128, -aria192, -aria256, -camellia128, -camellia192,
       -camellia256, -des, -des3, -idea
           These options encrypt the private key with specified cipher 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, -f4, -3
           The public exponent to use, either 65537 or 3. The default is 65537.  The -3 option
           has been deprecated.

       -primes num
           Specify the number of primes to use while generating the RSA key. The num parameter
           must be a positive integer that is greater than 1 and less than 16.  If num is greater
           than 2, then the generated key is called a 'multi-prime' RSA key, which is defined in
           RFC 8017.

       -verbose
           Print extra details about the operations being performed.

       -traditional
           Write the key using the traditional PKCS#1 format instead of the PKCS#8 format.

       -rand files, -writerand file
           See "Random State Options" in openssl(1) for details.

       -engine id
           See "Engine Options" in openssl(1).  This option is deprecated.

       -provider name
       -provider-path path
       -propquery propq
           See "Provider Options" in openssl(1), provider(7), and property(7).

       numbits
           The size of the private key to generate in bits. This must be the last option
           specified. The default is 2048 and values less than 512 are not allowed.

NOTES

       RSA private key generation essentially involves the generation of two or more 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, *
       means the current prime starts a regenerating progress due to some failed tests. 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. But in general, more primes lead to less generation time of a key.

SEE ALSO

       openssl(1), openssl-genpkey(1), openssl-gendsa(1)

COPYRIGHT

       Copyright 2000-2023 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file except
       in compliance with the License.  You can obtain a copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.