openssl-genrsa - generate an RSA private key
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]
This command generates an RSA private key.
- -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.
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.
openssl(1),
openssl-genpkey(1),
openssl-gendsa(1)
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>.