1 =pod 2 3 =head1 NAME 4 5 openssl-rsa, 6 rsa - RSA key processing tool 7 8 =head1 SYNOPSIS 9 10 B<openssl> B<rsa> 11 [B<-help>] 12 [B<-inform PEM|DER>] 13 [B<-outform PEM|DER>] 14 [B<-in filename>] 15 [B<-passin arg>] 16 [B<-out filename>] 17 [B<-passout arg>] 18 [B<-aes128>] 19 [B<-aes192>] 20 [B<-aes256>] 21 [B<-aria128>] 22 [B<-aria192>] 23 [B<-aria256>] 24 [B<-camellia128>] 25 [B<-camellia192>] 26 [B<-camellia256>] 27 [B<-des>] 28 [B<-des3>] 29 [B<-idea>] 30 [B<-text>] 31 [B<-noout>] 32 [B<-modulus>] 33 [B<-check>] 34 [B<-pubin>] 35 [B<-pubout>] 36 [B<-RSAPublicKey_in>] 37 [B<-RSAPublicKey_out>] 38 [B<-engine id>] 39 40 =head1 DESCRIPTION 41 42 The B<rsa> command processes RSA keys. They can be converted between various 43 forms and their components printed out. B<Note> this command uses the 44 traditional SSLeay compatible format for private key encryption: newer 45 applications should use the more secure PKCS#8 format using the B<pkcs8> 46 utility. 47 48 =head1 OPTIONS 49 50 =over 4 51 52 =item B<-help> 53 54 Print out a usage message. 55 56 =item B<-inform DER|PEM> 57 58 This specifies the input format. The B<DER> option uses an ASN1 DER encoded 59 form compatible with the PKCS#1 RSAPrivateKey or SubjectPublicKeyInfo format. 60 The B<PEM> form is the default format: it consists of the B<DER> format base64 61 encoded with additional header and footer lines. On input PKCS#8 format private 62 keys are also accepted. 63 64 =item B<-outform DER|PEM> 65 66 This specifies the output format, the options have the same meaning and default 67 as the B<-inform> option. 68 69 =item B<-in filename> 70 71 This specifies the input filename to read a key from or standard input if this 72 option is not specified. If the key is encrypted a pass phrase will be 73 prompted for. 74 75 =item B<-passin arg> 76 77 The input file password source. For more information about the format of B<arg> 78 see L<openssl(1)/Pass Phrase Options>. 79 80 =item B<-out filename> 81 82 This specifies the output filename to write a key to or standard output if this 83 option is not specified. If any encryption options are set then a pass phrase 84 will be prompted for. The output filename should B<not> be the same as the input 85 filename. 86 87 =item B<-passout password> 88 89 The output file password source. For more information about the format of B<arg> 90 see L<openssl(1)/Pass Phrase Options>. 91 92 =item B<-aes128>, B<-aes192>, B<-aes256>, B<-aria128>, B<-aria192>, B<-aria256>, B<-camellia128>, B<-camellia192>, B<-camellia256>, B<-des>, B<-des3>, B<-idea> 93 94 These options encrypt the private key with the specified 95 cipher before outputting it. A pass phrase is prompted for. 96 If none of these options is specified the key is written in plain text. This 97 means that using the B<rsa> utility to read in an encrypted key with no 98 encryption option can be used to remove the pass phrase from a key, or by 99 setting the encryption options it can be use to add or change the pass phrase. 100 These options can only be used with PEM format output files. 101 102 =item B<-text> 103 104 Prints out the various public or private key components in 105 plain text in addition to the encoded version. 106 107 =item B<-noout> 108 109 This option prevents output of the encoded version of the key. 110 111 =item B<-modulus> 112 113 This option prints out the value of the modulus of the key. 114 115 =item B<-check> 116 117 This option checks the consistency of an RSA private key. 118 119 =item B<-pubin> 120 121 By default a private key is read from the input file: with this 122 option a public key is read instead. 123 124 =item B<-pubout> 125 126 By default a private key is output: with this option a public 127 key will be output instead. This option is automatically set if 128 the input is a public key. 129 130 =item B<-RSAPublicKey_in>, B<-RSAPublicKey_out> 131 132 Like B<-pubin> and B<-pubout> except B<RSAPublicKey> format is used instead. 133 134 =item B<-engine id> 135 136 Specifying an engine (by its unique B<id> string) will cause B<rsa> 137 to attempt to obtain a functional reference to the specified engine, 138 thus initialising it if needed. The engine will then be set as the default 139 for all available algorithms. 140 141 =back 142 143 =head1 NOTES 144 145 The PEM private key format uses the header and footer lines: 146 147 -----BEGIN RSA PRIVATE KEY----- 148 -----END RSA PRIVATE KEY----- 149 150 The PEM public key format uses the header and footer lines: 151 152 -----BEGIN PUBLIC KEY----- 153 -----END PUBLIC KEY----- 154 155 The PEM B<RSAPublicKey> format uses the header and footer lines: 156 157 -----BEGIN RSA PUBLIC KEY----- 158 -----END RSA PUBLIC KEY----- 159 160 =head1 EXAMPLES 161 162 To remove the pass phrase on an RSA private key: 163 164 openssl rsa -in key.pem -out keyout.pem 165 166 To encrypt a private key using triple DES: 167 168 openssl rsa -in key.pem -des3 -out keyout.pem 169 170 To convert a private key from PEM to DER format: 171 172 openssl rsa -in key.pem -outform DER -out keyout.der 173 174 To print out the components of a private key to standard output: 175 176 openssl rsa -in key.pem -text -noout 177 178 To just output the public part of a private key: 179 180 openssl rsa -in key.pem -pubout -out pubkey.pem 181 182 Output the public part of a private key in B<RSAPublicKey> format: 183 184 openssl rsa -in key.pem -RSAPublicKey_out -out pubkey.pem 185 186 =head1 BUGS 187 188 There should be an option that automatically handles .key files, 189 without having to manually edit them. 190 191 =head1 SEE ALSO 192 193 L<pkcs8(1)>, L<dsa(1)>, L<genrsa(1)>, 194 L<gendsa(1)> 195 196 =head1 COPYRIGHT 197 198 Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved. 199 200 Licensed under the OpenSSL license (the "License"). You may not use 201 this file except in compliance with the License. You can obtain a copy 202 in the file LICENSE in the source distribution or at 203 L<https://www.openssl.org/source/license.html>. 204 205 =cut 206
Indexes created Sun Aug 02 00:25:04 UTC 2026