1 =pod 2 {- OpenSSL::safe::output_do_not_edit_headers(); -} 3 4 =head1 NAME 5 6 openssl-kdf - perform Key Derivation Function operations 7 8 =head1 SYNOPSIS 9 10 B<openssl kdf> 11 [B<-help>] 12 [B<-cipher>] 13 [B<-digest>] 14 [B<-mac>] 15 [B<-kdfopt> I<nm>:I<v>] 16 [B<-keylen> I<num>] 17 [B<-out> I<filename>] 18 [B<-binary>] 19 {- $OpenSSL::safe::opt_provider_synopsis -} 20 I<kdf_name> 21 22 =head1 DESCRIPTION 23 24 The key derivation functions generate a derived key from either a secret or 25 password. 26 27 =head1 OPTIONS 28 29 =over 4 30 31 =item B<-help> 32 33 Print a usage message. 34 35 =item B<-keylen> I<num> 36 37 The output size of the derived key. This field is required. 38 39 =item B<-out> I<filename> 40 41 Filename to output to, or standard output by default. 42 43 =item B<-binary> 44 45 Output the derived key in binary form. Uses hexadecimal text format if not specified. 46 47 =item B<-cipher> I<name> 48 49 Specify the cipher to be used by the KDF. 50 Not all KDFs require a cipher and it is an error to use this option in such 51 cases. 52 53 =item B<-digest> I<name> 54 55 Specify the digest to be used by the KDF. 56 Not all KDFs require a digest and it is an error to use this option in such 57 cases. 58 To see the list of supported digests, use C<openssl list -digest-commands>. 59 60 =item B<-mac> I<name> 61 62 Specify the MAC to be used by the KDF. 63 Not all KDFs require a MAC and it is an error to use this option in such 64 cases. 65 66 =item B<-kdfopt> I<nm>:I<v> 67 68 Passes options to the KDF algorithm. 69 A comprehensive list of parameters can be found in L<EVP_KDF(3)/PARAMETERS>. 70 Common parameter names used by EVP_KDF_CTX_set_params() are: 71 72 =over 4 73 74 =item B<key:>I<string> 75 76 Specifies the secret key as an alphanumeric string (use if the key contains 77 printable characters only). 78 The string length must conform to any restrictions of the KDF algorithm. 79 A key must be specified for most KDF algorithms. 80 81 =item B<hexkey:>I<string> 82 83 Alternative to the B<key:> option where 84 the secret key is specified in hexadecimal form (two hex digits per byte). 85 86 =item B<pass:>I<string> 87 88 Specifies the password as an alphanumeric string (use if the password contains 89 printable characters only). 90 The password must be specified for PBKDF2 and scrypt. 91 92 =item B<hexpass:>I<string> 93 94 Alternative to the B<pass:> option where 95 the password is specified in hexadecimal form (two hex digits per byte). 96 97 =item B<salt:>I<string> 98 99 Specifies a non-secret unique cryptographic salt as an alphanumeric string 100 (use if it contains printable characters only). 101 The length must conform to any restrictions of the KDF algorithm. 102 A salt parameter is required for several KDF algorithms, 103 such as L<EVP_KDF-PBKDF2(7)>. 104 105 =item B<hexsalt:>I<string> 106 107 Alternative to the B<salt:> option where 108 the salt is specified in hexadecimal form (two hex digits per byte). 109 110 =item B<info:>I<string> 111 112 Some KDF implementations, such as L<EVP_KDF-HKDF(7)>, take an 'info' parameter 113 for binding the derived key material 114 to application- and context-specific information. 115 Specifies the info, fixed info, other info or shared info argument 116 as an alphanumeric string (use if it contains printable characters only). 117 The length must conform to any restrictions of the KDF algorithm. 118 119 =item B<hexinfo:>I<string> 120 121 Alternative to the B<info:> option where 122 the info is specified in hexadecimal form (two hex digits per byte). 123 124 =item B<digest:>I<string> 125 126 This option is identical to the B<-digest> option. 127 128 =item B<cipher:>I<string> 129 130 This option is identical to the B<-cipher> option. 131 132 =item B<mac:>I<string> 133 134 This option is identical to the B<-mac> option. 135 136 =back 137 138 {- $OpenSSL::safe::opt_provider_item -} 139 140 =item I<kdf_name> 141 142 Specifies the name of a supported KDF algorithm which will be used. 143 The supported algorithms names include TLS1-PRF, HKDF, SSKDF, PBKDF2, 144 SSHKDF, X942KDF-ASN1, X942KDF-CONCAT, X963KDF and SCRYPT. 145 146 =back 147 148 =head1 EXAMPLES 149 150 Use TLS1-PRF to create a hex-encoded derived key from a secret key and seed: 151 152 openssl kdf -keylen 16 -kdfopt digest:SHA2-256 -kdfopt key:secret \ 153 -kdfopt seed:seed TLS1-PRF 154 155 Use HKDF to create a hex-encoded derived key from a secret key, salt and info: 156 157 openssl kdf -keylen 10 -kdfopt digest:SHA2-256 -kdfopt key:secret \ 158 -kdfopt salt:salt -kdfopt info:label HKDF 159 160 Use SSKDF with KMAC to create a hex-encoded derived key from a secret key, salt and info: 161 162 openssl kdf -keylen 64 -kdfopt mac:KMAC-128 -kdfopt maclen:20 \ 163 -kdfopt hexkey:b74a149a161545 -kdfopt hexinfo:348a37a2 \ 164 -kdfopt hexsalt:3638271ccd68a2 SSKDF 165 166 Use SSKDF with HMAC to create a hex-encoded derived key from a secret key, salt and info: 167 168 openssl kdf -keylen 16 -kdfopt mac:HMAC -kdfopt digest:SHA2-256 \ 169 -kdfopt hexkey:b74a149a -kdfopt hexinfo:348a37a2 \ 170 -kdfopt hexsalt:3638271c SSKDF 171 172 Use SSKDF with Hash to create a hex-encoded derived key from a secret key, salt and info: 173 174 openssl kdf -keylen 14 -kdfopt digest:SHA2-256 \ 175 -kdfopt hexkey:6dbdc23f045488 \ 176 -kdfopt hexinfo:a1b2c3d4 SSKDF 177 178 Use SSHKDF to create a hex-encoded derived key from a secret key, hash and session_id: 179 180 openssl kdf -keylen 16 -kdfopt digest:SHA2-256 \ 181 -kdfopt hexkey:0102030405 \ 182 -kdfopt hexxcghash:06090A \ 183 -kdfopt hexsession_id:01020304 \ 184 -kdfopt type:A SSHKDF 185 186 Use PBKDF2 to create a hex-encoded derived key from a password and salt: 187 188 openssl kdf -keylen 32 -kdfopt digest:SHA256 -kdfopt pass:password \ 189 -kdfopt salt:salt -kdfopt iter:2 PBKDF2 190 191 Use scrypt to create a hex-encoded derived key from a password and salt: 192 193 openssl kdf -keylen 64 -kdfopt pass:password -kdfopt salt:NaCl \ 194 -kdfopt n:1024 -kdfopt r:8 -kdfopt p:16 \ 195 -kdfopt maxmem_bytes:10485760 SCRYPT 196 197 =head1 NOTES 198 199 The KDF mechanisms that are available will depend on the options 200 used when building OpenSSL. 201 202 =head1 SEE ALSO 203 204 L<openssl(1)>, 205 L<openssl-pkeyutl(1)>, 206 L<EVP_KDF(3)>, 207 L<EVP_KDF-SCRYPT(7)>, 208 L<EVP_KDF-TLS1_PRF(7)>, 209 L<EVP_KDF-PBKDF2(7)>, 210 L<EVP_KDF-HKDF(7)>, 211 L<EVP_KDF-SS(7)>, 212 L<EVP_KDF-SSHKDF(7)>, 213 L<EVP_KDF-X942-ASN1(7)>, 214 L<EVP_KDF-X942-CONCAT(7)>, 215 L<EVP_KDF-X963(7)> 216 217 =head1 HISTORY 218 219 Added in OpenSSL 3.0 220 221 =head1 COPYRIGHT 222 223 Copyright 2019-2023 The OpenSSL Project Authors. All Rights Reserved. 224 225 Licensed under the Apache License 2.0 (the "License"). You may not use 226 this file except in compliance with the License. You can obtain a copy 227 in the file LICENSE in the source distribution or at 228 L<https://www.openssl.org/source/license.html>. 229 230 =cut 231
Indexes created Sun May 03 00:22:47 UTC 2026