RSA(1SSL) OpenSSL RSA(1SSL)
NAME
openssl-rsa, rsa - RSA key processing tool
SYNOPSIS
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]
DESCRIPTION
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.
OPTIONS
-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 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
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 the PASS PHRASE ARGUMENTS section 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.
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 PEM RSAPublicKey format uses the header and footer lines:
-----BEGIN RSA PUBLIC KEY-----
-----END RSA PUBLIC KEY-----
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
Output the public part of a private key in RSAPublicKey format:
openssl rsa -in key.pem -RSAPublicKey_out -out pubkey.pem
BUGS
There should be an option that automatically handles .key files,
without having to manually edit them.
SEE ALSO
pkcs8(1), dsa(1), genrsa(1), gendsa(1)
COPYRIGHT
Copyright 2000-2018 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>.
1.1.1g 2020-04-21 RSA(1SSL)