include/crypto/kdf_sp800108.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2
   3 /*
   4  * Copyright (C) 2021, Stephan Mueller <smueller@chronox.de>
   5  */
   6
   7 #ifndef _CRYPTO_KDF108_H
   8 #define _CRYPTO_KDF108_H
   9
  10 #include <crypto/hash.h>
  11 #include <linux/uio.h>
  12
  13 /**
  14  * Counter KDF generate operation according to SP800-108 section 5.1
  15  * as well as SP800-56A section 5.8.1 (Single-step KDF).
  16  *
  17  * @kmd Keyed message digest whose key was set with crypto_kdf108_setkey or
  18  *      unkeyed message digest
  19  * @info optional context and application specific information - this may be
  20  *       NULL
  21  * @info_vec number of optional context/application specific information entries
  22  * @dst destination buffer that the caller already allocated
  23  * @dlen length of the destination buffer - the KDF derives that amount of
  24  *       bytes.
  25  *
  26  * To comply with SP800-108, the caller must provide Label || 0x00 || Context
  27  * in the info parameter.
  28  *
  29  * @return 0 on success, < 0 on error
  30  */
  31 int crypto_kdf108_ctr_generate(struct crypto_shash *kmd,
  32                                const struct kvec *info, unsigned int info_nvec,
  33                                u8 *dst, unsigned int dlen);
  34
  35 /**
  36  * Counter KDF setkey operation
  37  *
  38  * @kmd Keyed message digest allocated by the caller. The key should not have
  39  *      been set.
  40  * @key Seed key to be used to initialize the keyed message digest context.
  41  * @keylen This length of the key buffer.
  42  * @ikm The SP800-108 KDF does not support IKM - this parameter must be NULL
  43  * @ikmlen This parameter must be 0.
  44  *
  45  * According to SP800-108 section 7.2, the seed key must be at least as large as
  46  * the message digest size of the used keyed message digest. This limitation
  47  * is enforced by the implementation.
  48  *
  49  * SP800-108 allows the use of either a HMAC or a hash primitive. When
  50  * the caller intends to use a hash primitive, the call to
  51  * crypto_kdf108_setkey is not required and the key derivation operation can
  52  * immediately performed using crypto_kdf108_ctr_generate after allocating
  53  * a handle.
  54  *
  55  * @return 0 on success, < 0 on error
  56  */
  57 int crypto_kdf108_setkey(struct crypto_shash *kmd,
  58                          const u8 *key, size_t keylen,
  59                          const u8 *ikm, size_t ikmlen);
  60
  61 #endif /* _CRYPTO_KDF108_H */