tls_kdf.c File Reference

TLS key derivation functions. More...

#include "core/crypto.h"
#include "kdf/tls_kdf.h"
#include "kdf/hkdf.h"
#include "mac/hmac.h"

Go to the source code of this file.

Macros
#define	TRACE_LEVEL   CRYPTO_TRACE_LEVEL

Functions
error_t	tlsPrf (const uint8_t *secret, size_t secretLen, const char_t *label, const uint8_t *seed, size_t seedLen, uint8_t *output, size_t outputLen)
	Pseudorandom function (TLS 1.0 and 1.1) More...
error_t	tls12Prf (const HashAlgo *hashAlgo, const uint8_t *secret, size_t secretLen, const char_t *label, const uint8_t *seed, size_t seedLen, uint8_t *output, size_t outputLen)
	Pseudorandom function (TLS 1.2) More...
error_t	hkdfExpandLabel (const HashAlgo *hashAlgo, const uint8_t *secret, size_t secretLen, const char_t *prefix, const char_t *label, const uint8_t *context, size_t contextLen, uint8_t *output, size_t outputLen)
	HKDF-Expand-Label function (TLS 1.3) More...

Detailed Description

TLS key derivation functions.

License

SPDX-License-Identifier: GPL-2.0-or-later

Copyright (C) 2010-2026 Oryx Embedded SARL. All rights reserved.

This file is part of CycloneCRYPTO Open.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

Author

Oryx Embedded SARL (www.oryx-embedded.com)

Version

2.6.6

Definition in file tls_kdf.c.

Macro Definition Documentation

TRACE_LEVEL

#define TRACE_LEVEL   CRYPTO_TRACE_LEVEL

Definition at line 32 of file tls_kdf.c.

Function Documentation

hkdfExpandLabel()

error_t hkdfExpandLabel	(	const HashAlgo *	hashAlgo,
		const uint8_t *	secret,
		size_t	secretLen,
		const char_t *	prefix,
		const char_t *	label,
		const uint8_t *	context,
		size_t	contextLen,
		uint8_t *	output,
		size_t	outputLen
	)

HKDF-Expand-Label function (TLS 1.3)

Parameters

[in]	hashAlgo	Hash function used by HKDF
[in]	secret	Pointer to the secret
[in]	secretLen	Length of the secret
[in]	prefix	Label prefix ("tls13 " for TLS, "dtls13" for DTLS)
[in]	label	Identifying label (NULL-terminated string)
[in]	context	Pointer to the upper-layer context
[in]	contextLen	Length of the upper-layer context
[out]	output	Pointer to the output
[in]	outputLen	Desired output length

Returns

Error code

Definition at line 270 of file tls_kdf.c.

tls12Prf()

error_t tls12Prf	(	const HashAlgo *	hashAlgo,
		const uint8_t *	secret,
		size_t	secretLen,
		const char_t *	label,
		const uint8_t *	seed,
		size_t	seedLen,
		uint8_t *	output,
		size_t	outputLen
	)

Pseudorandom function (TLS 1.2)

The pseudorandom function (PRF) takes as input a secret, a seed, and an identifying label and produces an output of arbitrary length. This function is used to expand secrets into blocks of data for the purpose of key generation

Parameters

[in]	hashAlgo	Hash function used to compute PRF
[in]	secret	Pointer to the secret
[in]	secretLen	Length of the secret
[in]	label	Identifying label (NULL-terminated string)
[in]	seed	Pointer to the seed
[in]	seedLen	Length of the seed
[out]	output	Pointer to the output
[in]	outputLen	Desired output length

Returns

Error code

Definition at line 187 of file tls_kdf.c.

tlsPrf()

error_t tlsPrf	(	const uint8_t *	secret,
		size_t	secretLen,
		const char_t *	label,
		const uint8_t *	seed,
		size_t	seedLen,
		uint8_t *	output,
		size_t	outputLen
	)

Pseudorandom function (TLS 1.0 and 1.1)

The pseudorandom function (PRF) takes as input a secret, a seed, and an identifying label and produces an output of arbitrary length. This function is used to expand secrets into blocks of data for the purpose of key generation

Parameters

[in]	secret	Pointer to the secret
[in]	secretLen	Length of the secret
[in]	label	Identifying label (NULL-terminated string)
[in]	seed	Pointer to the seed
[in]	seedLen	Length of the seed
[out]	output	Pointer to the output
[in]	outputLen	Desired output length

Returns

Error code

Definition at line 62 of file tls_kdf.c.