1RSA(1)                              OpenSSL                             RSA(1)
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NAME

6       openssl-rsa, rsa - RSA key processing tool
7

SYNOPSIS

9       openssl rsa [-help] [-inform PEM|DER] [-outform PEM|DER] [-in filename]
10       [-passin arg] [-out filename] [-passout arg] [-aes128] [-aes192]
11       [-aes256] [-aria128] [-aria192] [-aria256] [-camellia128]
12       [-camellia192] [-camellia256] [-des] [-des3] [-idea] [-text] [-noout]
13       [-modulus] [-check] [-pubin] [-pubout] [-RSAPublicKey_in]
14       [-RSAPublicKey_out] [-engine id]
15

DESCRIPTION

17       The rsa command processes RSA keys. They can be converted between
18       various forms and their components printed out. Note this command uses
19       the traditional SSLeay compatible format for private key encryption:
20       newer applications should use the more secure PKCS#8 format using the
21       pkcs8 utility.
22

OPTIONS

24       -help
25           Print out a usage message.
26
27       -inform DER|PEM
28           This specifies the input format. The DER option uses an ASN1 DER
29           encoded form compatible with the PKCS#1 RSAPrivateKey or
30           SubjectPublicKeyInfo format.  The PEM form is the default format:
31           it consists of the DER format base64 encoded with additional header
32           and footer lines. On input PKCS#8 format private keys are also
33           accepted.
34
35       -outform DER|PEM
36           This specifies the output format, the options have the same meaning
37           and default as the -inform option.
38
39       -in filename
40           This specifies the input filename to read a key from or standard
41           input if this option is not specified. If the key is encrypted a
42           pass phrase will be prompted for.
43
44       -passin arg
45           The input file password source. For more information about the
46           format of arg see "Pass Phrase Options" in openssl(1).
47
48       -out filename
49           This specifies the output filename to write a key to or standard
50           output if this option is not specified. If any encryption options
51           are set then a pass phrase will be prompted for. The output
52           filename should not be the same as the input filename.
53
54       -passout password
55           The output file password source. For more information about the
56           format of arg see "Pass Phrase Options" in openssl(1).
57
58       -aes128, -aes192, -aes256, -aria128, -aria192, -aria256, -camellia128,
59       -camellia192, -camellia256, -des, -des3, -idea
60           These options encrypt the private key with the specified cipher
61           before outputting it. A pass phrase is prompted for.  If none of
62           these options is specified the key is written in plain text. This
63           means that using the rsa utility to read in an encrypted key with
64           no encryption option can be used to remove the pass phrase from a
65           key, or by setting the encryption options it can be use to add or
66           change the pass phrase.  These options can only be used with PEM
67           format output files.
68
69       -text
70           Prints out the various public or private key components in plain
71           text in addition to the encoded version.
72
73       -noout
74           This option prevents output of the encoded version of the key.
75
76       -modulus
77           This option prints out the value of the modulus of the key.
78
79       -check
80           This option checks the consistency of an RSA private key.
81
82       -pubin
83           By default a private key is read from the input file: with this
84           option a public key is read instead.
85
86       -pubout
87           By default a private key is output: with this option a public key
88           will be output instead. This option is automatically set if the
89           input is a public key.
90
91       -RSAPublicKey_in, -RSAPublicKey_out
92           Like -pubin and -pubout except RSAPublicKey format is used instead.
93
94       -engine id
95           Specifying an engine (by its unique id string) will cause rsa to
96           attempt to obtain a functional reference to the specified engine,
97           thus initialising it if needed. The engine will then be set as the
98           default for all available algorithms.
99

NOTES

101       The PEM private key format uses the header and footer lines:
102
103        -----BEGIN RSA PRIVATE KEY-----
104        -----END RSA PRIVATE KEY-----
105
106       The PEM public key format uses the header and footer lines:
107
108        -----BEGIN PUBLIC KEY-----
109        -----END PUBLIC KEY-----
110
111       The PEM RSAPublicKey format uses the header and footer lines:
112
113        -----BEGIN RSA PUBLIC KEY-----
114        -----END RSA PUBLIC KEY-----
115

EXAMPLES

117       To remove the pass phrase on an RSA private key:
118
119        openssl rsa -in key.pem -out keyout.pem
120
121       To encrypt a private key using triple DES:
122
123        openssl rsa -in key.pem -des3 -out keyout.pem
124
125       To convert a private key from PEM to DER format:
126
127        openssl rsa -in key.pem -outform DER -out keyout.der
128
129       To print out the components of a private key to standard output:
130
131        openssl rsa -in key.pem -text -noout
132
133       To just output the public part of a private key:
134
135        openssl rsa -in key.pem -pubout -out pubkey.pem
136
137       Output the public part of a private key in RSAPublicKey format:
138
139        openssl rsa -in key.pem -RSAPublicKey_out -out pubkey.pem
140

BUGS

142       There should be an option that automatically handles .key files,
143       without having to manually edit them.
144

SEE ALSO

146       pkcs8(1), dsa(1), genrsa(1), gendsa(1)
147
149       Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
150
151       Licensed under the OpenSSL license (the "License").  You may not use
152       this file except in compliance with the License.  You can obtain a copy
153       in the file LICENSE in the source distribution or at
154       <https://www.openssl.org/source/license.html>.
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1581.1.1l                            2021-09-15                            RSA(1)
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