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Always turn off hyphenation; it makes .\" way too many mistakes in technical documents. .if n .ad l .nh .SH "NAME" openssl\-kdf \- perform Key Derivation Function operations .SH "SYNOPSIS" .IX Header "SYNOPSIS" \&\fBopenssl kdf\fR [\fB\-help\fR] [\fB\-cipher\fR] [\fB\-digest\fR] [\fB\-mac\fR] [\fB\-kdfopt\fR \fInm\fR:\fIv\fR] [\fB\-keylen\fR \fInum\fR] [\fB\-out\fR \fIfilename\fR] [\fB\-binary\fR] [\fB\-provider\fR \fIname\fR] [\fB\-provider\-path\fR \fIpath\fR] [\fB\-propquery\fR \fIpropq\fR] \&\fIkdf_name\fR .SH "DESCRIPTION" .IX Header "DESCRIPTION" The key derivation functions generate a derived key from either a secret or password. .SH "OPTIONS" .IX Header "OPTIONS" .IP "\fB\-help\fR" 4 .IX Item "-help" Print a usage message. .IP "\fB\-keylen\fR \fInum\fR" 4 .IX Item "-keylen num" The output size of the derived key. This field is required. .IP "\fB\-out\fR \fIfilename\fR" 4 .IX Item "-out filename" Filename to output to, or standard output by default. .IP "\fB\-binary\fR" 4 .IX Item "-binary" Output the derived key in binary form. Uses hexadecimal text format if not specified. .IP "\fB\-cipher\fR \fIname\fR" 4 .IX Item "-cipher name" Specify the cipher to be used by the \s-1KDF.\s0 Not all KDFs require a cipher and it is an error to use this option in such cases. .IP "\fB\-digest\fR \fIname\fR" 4 .IX Item "-digest name" Specify the digest to be used by the \s-1KDF.\s0 Not all KDFs require a digest and it is an error to use this option in such cases. To see the list of supported digests, use \f(CW\*(C`openssl list \-digest\-commands\*(C'\fR. .IP "\fB\-mac\fR \fIname\fR" 4 .IX Item "-mac name" Specify the \s-1MAC\s0 to be used by the \s-1KDF.\s0 Not all KDFs require a \s-1MAC\s0 and it is an error to use this option in such cases. .IP "\fB\-kdfopt\fR \fInm\fR:\fIv\fR" 4 .IX Item "-kdfopt nm:v" Passes options to the \s-1KDF\s0 algorithm. A comprehensive list of parameters can be found in the \s-1EVP_KDF_CTX\s0 implementation documentation. Common parameter names used by \fBEVP_KDF_CTX_set_params()\fR are: .RS 4 .IP "\fBkey:\fR\fIstring\fR" 4 .IX Item "key:string" Specifies the secret key as an alphanumeric string (use if the key contains printable characters only). The string length must conform to any restrictions of the \s-1KDF\s0 algorithm. A key must be specified for most \s-1KDF\s0 algorithms. .IP "\fBhexkey:\fR\fIstring\fR" 4 .IX Item "hexkey:string" Specifies the secret key in hexadecimal form (two hex digits per byte). The key length must conform to any restrictions of the \s-1KDF\s0 algorithm. A key must be specified for most \s-1KDF\s0 algorithms. .IP "\fBpass:\fR\fIstring\fR" 4 .IX Item "pass:string" Specifies the password as an alphanumeric string (use if the password contains printable characters only). The password must be specified for \s-1PBKDF2\s0 and scrypt. .IP "\fBhexpass:\fR\fIstring\fR" 4 .IX Item "hexpass:string" Specifies the password in hexadecimal form (two hex digits per byte). The password must be specified for \s-1PBKDF2\s0 and scrypt. .IP "\fBdigest:\fR\fIstring\fR" 4 .IX Item "digest:string" This option is identical to the \fB\-digest\fR option. .IP "\fBcipher:\fR\fIstring\fR" 4 .IX Item "cipher:string" This option is identical to the \fB\-cipher\fR option. .IP "\fBmac:\fR\fIstring\fR" 4 .IX Item "mac:string" This option is identical to the \fB\-mac\fR option. .RE .RS 4 .RE .IP "\fB\-provider\fR \fIname\fR" 4 .IX Item "-provider name" .PD 0 .IP "\fB\-provider\-path\fR \fIpath\fR" 4 .IX Item "-provider-path path" .IP "\fB\-propquery\fR \fIpropq\fR" 4 .IX Item "-propquery propq" .PD See \*(L"Provider Options\*(R" in \fBopenssl\fR\|(1), \fBprovider\fR\|(7), and \fBproperty\fR\|(7). .IP "\fIkdf_name\fR" 4 .IX Item "kdf_name" Specifies the name of a supported \s-1KDF\s0 algorithm which will be used. The supported algorithms names include \s-1TLS1\-PRF, HKDF, SSKDF, PBKDF2, SSHKDF, X942KDF\-ASN1, X942KDF\-CONCAT, X963KDF\s0 and \s-1SCRYPT.\s0 .SH "EXAMPLES" .IX Header "EXAMPLES" Use \s-1TLS1\-PRF\s0 to create a hex-encoded derived key from a secret key and seed: .PP .Vb 2 \& openssl kdf \-keylen 16 \-kdfopt digest:SHA2\-256 \-kdfopt key:secret \e \& \-kdfopt seed:seed TLS1\-PRF .Ve .PP Use \s-1HKDF\s0 to create a hex-encoded derived key from a secret key, salt and info: .PP .Vb 2 \& openssl kdf \-keylen 10 \-kdfopt digest:SHA2\-256 \-kdfopt key:secret \e \& \-kdfopt salt:salt \-kdfopt info:label HKDF .Ve .PP Use \s-1SSKDF\s0 with \s-1KMAC\s0 to create a hex-encoded derived key from a secret key, salt and info: .PP .Vb 3 \& openssl kdf \-keylen 64 \-kdfopt mac:KMAC\-128 \-kdfopt maclen:20 \e \& \-kdfopt hexkey:b74a149a161545 \-kdfopt hexinfo:348a37a2 \e \& \-kdfopt hexsalt:3638271ccd68a2 SSKDF .Ve .PP Use \s-1SSKDF\s0 with \s-1HMAC\s0 to create a hex-encoded derived key from a secret key, salt and info: .PP .Vb 3 \& openssl kdf \-keylen 16 \-kdfopt mac:HMAC \-kdfopt digest:SHA2\-256 \e \& \-kdfopt hexkey:b74a149a \-kdfopt hexinfo:348a37a2 \e \& \-kdfopt hexsalt:3638271c SSKDF .Ve .PP Use \s-1SSKDF\s0 with Hash to create a hex-encoded derived key from a secret key, salt and info: .PP .Vb 3 \& openssl kdf \-keylen 14 \-kdfopt digest:SHA2\-256 \e \& \-kdfopt hexkey:6dbdc23f045488 \e \& \-kdfopt hexinfo:a1b2c3d4 SSKDF .Ve .PP Use \s-1SSHKDF\s0 to create a hex-encoded derived key from a secret key, hash and session_id: .PP .Vb 5 \& openssl kdf \-keylen 16 \-kdfopt digest:SHA2\-256 \e \& \-kdfopt hexkey:0102030405 \e \& \-kdfopt hexxcghash:06090A \e \& \-kdfopt hexsession_id:01020304 \e \& \-kdfopt type:A SSHKDF .Ve .PP Use \s-1PBKDF2\s0 to create a hex-encoded derived key from a password and salt: .PP .Vb 2 \& openssl kdf \-keylen 32 \-kdfopt digest:SHA256 \-kdfopt pass:password \e \& \-kdfopt salt:salt \-kdfopt iter:2 PBKDF2 .Ve .PP Use scrypt to create a hex-encoded derived key from a password and salt: .PP .Vb 3 \& openssl kdf \-keylen 64 \-kdfopt pass:password \-kdfopt salt:NaCl \e \& \-kdfopt n:1024 \-kdfopt r:8 \-kdfopt p:16 \e \& \-kdfopt maxmem_bytes:10485760 SCRYPT .Ve .SH "NOTES" .IX Header "NOTES" The \s-1KDF\s0 mechanisms that are available will depend on the options used when building OpenSSL. .SH "SEE ALSO" .IX Header "SEE ALSO" \&\fBopenssl\fR\|(1), \&\fBopenssl\-pkeyutl\fR\|(1), \&\s-1\fBEVP_KDF\s0\fR\|(3), \&\s-1\fBEVP_KDF\-SCRYPT\s0\fR\|(7), \&\s-1\fBEVP_KDF\-TLS1_PRF\s0\fR\|(7), \&\s-1\fBEVP_KDF\-PBKDF2\s0\fR\|(7), \&\s-1\fBEVP_KDF\-HKDF\s0\fR\|(7), \&\s-1\fBEVP_KDF\-SS\s0\fR\|(7), \&\s-1\fBEVP_KDF\-SSHKDF\s0\fR\|(7), \&\s-1\fBEVP_KDF\-X942\-ASN1\s0\fR\|(7), \&\s-1\fBEVP_KDF\-X942\-CONCAT\s0\fR\|(7), \&\s-1\fBEVP_KDF\-X963\s0\fR\|(7) .SH "HISTORY" .IX Header "HISTORY" Added in OpenSSL 3.0 .SH "COPYRIGHT" .IX Header "COPYRIGHT" Copyright 2019\-2022 The OpenSSL Project Authors. All Rights Reserved. .PP Licensed under the Apache License 2.0 (the \*(L"License\*(R"). You may not use this file except in compliance with the License. You can obtain a copy in the file \s-1LICENSE\s0 in the source distribution or at .