openssl-rsa, rsa - RSA key processing tool
openssl rsa [-help] [-inform PEM|DER]
[-outform PEM|DER] [-in filename] [-passin arg]
[-out filename] [-passout arg] [-aes128]
[-aes192] [-aes256] [-aria128] [-aria192]
[-aria256] [-camellia128] [-camellia192]
[-camellia256] [-des] [-des3] [-idea]
[-text] [-noout] [-modulus] [-check]
[-pubin] [-pubout] [-RSAPublicKey_in]
[-RSAPublicKey_out] [-engine id]
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.
- -help
- Print out a usage message.
- -inform
DER|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.
- -outform
DER|PEM
- This specifies the output format, the options have the same meaning and
default 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 "Pass Phrase Options" 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 "Pass Phrase Options" in openssl(1).
- -aes128,
-aes192, -aes256, -aria128, -aria192,
-aria256, -camellia128, -camellia192,
-camellia256, -des, -des3, -idea
- These options encrypt the private key with the specified cipher 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.
- -RSAPublicKey_in,
-RSAPublicKey_out
- Like -pubin and -pubout except RSAPublicKey format is
used instead.
- -engine id
- Specifying an engine (by its unique id string) will cause
rsa 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.
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 PEM RSAPublicKey format uses the header and footer
lines:
-----BEGIN RSA PUBLIC KEY-----
-----END RSA PUBLIC KEY-----
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
Output the public part of a private key in RSAPublicKey
format:
openssl rsa -in key.pem -RSAPublicKey_out -out pubkey.pem
There should be an option that automatically handles .key files,
without having to manually edit them.
pkcs8(1), dsa(1), genrsa(1),
gendsa(1)
Copyright 2000-2021 The OpenSSL Project Authors. All Rights
Reserved.
Licensed under the OpenSSL license (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>.