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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * NH hash function for Adiantum
4 */
5
6#ifndef _CRYPTO_NH_H
7#define _CRYPTO_NH_H
8
9#include <linux/types.h>
10
11/* NH parameterization: */
12
13/* Endianness: little */
14/* Word size: 32 bits (works well on NEON, SSE2, AVX2) */
15
16/* Stride: 2 words (optimal on ARM32 NEON; works okay on other CPUs too) */
17#define NH_PAIR_STRIDE 2
18#define NH_MESSAGE_UNIT (NH_PAIR_STRIDE * 2 * sizeof(u32))
19
20/* Num passes (Toeplitz iteration count): 4, to give ε = 2^{-128} */
21#define NH_NUM_PASSES 4
22#define NH_HASH_BYTES (NH_NUM_PASSES * sizeof(u64))
23
24/* Max message size: 1024 bytes (32x compression factor) */
25#define NH_NUM_STRIDES 64
26#define NH_MESSAGE_WORDS (NH_PAIR_STRIDE * 2 * NH_NUM_STRIDES)
27#define NH_MESSAGE_BYTES (NH_MESSAGE_WORDS * sizeof(u32))
28#define NH_KEY_WORDS (NH_MESSAGE_WORDS + \
29 NH_PAIR_STRIDE * 2 * (NH_NUM_PASSES - 1))
30#define NH_KEY_BYTES (NH_KEY_WORDS * sizeof(u32))
31
32/**
33 * nh() - NH hash function for Adiantum
34 * @key: The key. @message_len + 48 bytes of it are used. This is NH_KEY_BYTES
35 * if @message_len has its maximum length of NH_MESSAGE_BYTES.
36 * @message: The message
37 * @message_len: The message length in bytes. Must be a multiple of 16
38 * (NH_MESSAGE_UNIT) and at most 1024 (NH_MESSAGE_BYTES).
39 * @hash: (output) The resulting hash value
40 *
41 * Note: the pseudocode for NH in the Adiantum paper iterates over 1024-byte
42 * segments of the message, computes a 32-byte hash for each, and returns all
43 * the hashes concatenated together. In contrast, this function just hashes one
44 * segment and returns one hash. It's the caller's responsibility to call this
45 * function for each 1024-byte segment and collect all the hashes.
46 *
47 * Context: Any context.
48 */
49void nh(const u32 *key, const u8 *message, size_t message_len,
50 __le64 hash[NH_NUM_PASSES]);
51
52#endif /* _CRYPTO_NH_H */