include/crypto/kdf_sp800108.h

0001 /* SPDX-License-Identifier: GPL-2.0 */
0002
0003 /*
0004  * Copyright (C) 2021, Stephan Mueller <smueller@chronox.de>
0005  */
0006
0007 #ifndef _CRYPTO_KDF108_H
0008 #define _CRYPTO_KDF108_H
0009
0010 #include <crypto/hash.h>
0011 #include <linux/uio.h>
0012
0013 /**
0014  * Counter KDF generate operation according to SP800-108 section 5.1
0015  * as well as SP800-56A section 5.8.1 (Single-step KDF).
0016  *
0017  * @kmd Keyed message digest whose key was set with crypto_kdf108_setkey or
0018  *  unkeyed message digest
0019  * @info optional context and application specific information - this may be
0020  *   NULL
0021  * @info_vec number of optional context/application specific information entries
0022  * @dst destination buffer that the caller already allocated
0023  * @dlen length of the destination buffer - the KDF derives that amount of
0024  *   bytes.
0025  *
0026  * To comply with SP800-108, the caller must provide Label || 0x00 || Context
0027  * in the info parameter.
0028  *
0029  * @return 0 on success, < 0 on error
0030  */
0031 int crypto_kdf108_ctr_generate(struct crypto_shash *kmd,
0032                    const struct kvec *info, unsigned int info_nvec,
0033                    u8 *dst, unsigned int dlen);
0034
0035 /**
0036  * Counter KDF setkey operation
0037  *
0038  * @kmd Keyed message digest allocated by the caller. The key should not have
0039  *  been set.
0040  * @key Seed key to be used to initialize the keyed message digest context.
0041  * @keylen This length of the key buffer.
0042  * @ikm The SP800-108 KDF does not support IKM - this parameter must be NULL
0043  * @ikmlen This parameter must be 0.
0044  *
0045  * According to SP800-108 section 7.2, the seed key must be at least as large as
0046  * the message digest size of the used keyed message digest. This limitation
0047  * is enforced by the implementation.
0048  *
0049  * SP800-108 allows the use of either a HMAC or a hash primitive. When
0050  * the caller intends to use a hash primitive, the call to
0051  * crypto_kdf108_setkey is not required and the key derivation operation can
0052  * immediately performed using crypto_kdf108_ctr_generate after allocating
0053  * a handle.
0054  *
0055  * @return 0 on success, < 0 on error
0056  */
0057 int crypto_kdf108_setkey(struct crypto_shash *kmd,
0058              const u8 *key, size_t keylen,
0059              const u8 *ikm, size_t ikmlen);
0060
0061 #endif /* _CRYPTO_KDF108_H */