From bb3b2cfeb206f5b10b859e134651b54120e3f530 Mon Sep 17 00:00:00 2001 From: Linus Walleij Date: Tue, 30 Jun 2026 18:05:56 +0100 Subject: ARM: 9480/1: entry: expand comment in __switch_to As per discussion between the developers in the mail thread linked, expand the comment in __switch_to so that readers of the code understand what is going on. Suggested-by: Mark Rutland Acked-by: Mark Rutland Signed-off-by: Linus Walleij > Signed-off-by: Russell King --- include/crypto/nh.h | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 include/crypto/nh.h (limited to 'include/crypto/nh.h') diff --git a/include/crypto/nh.h b/include/crypto/nh.h new file mode 100644 index 000000000..465e85bf2 --- /dev/null +++ b/include/crypto/nh.h @@ -0,0 +1,52 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * NH hash function for Adiantum + */ + +#ifndef _CRYPTO_NH_H +#define _CRYPTO_NH_H + +#include + +/* NH parameterization: */ + +/* Endianness: little */ +/* Word size: 32 bits (works well on NEON, SSE2, AVX2) */ + +/* Stride: 2 words (optimal on ARM32 NEON; works okay on other CPUs too) */ +#define NH_PAIR_STRIDE 2 +#define NH_MESSAGE_UNIT (NH_PAIR_STRIDE * 2 * sizeof(u32)) + +/* Num passes (Toeplitz iteration count): 4, to give ε = 2^{-128} */ +#define NH_NUM_PASSES 4 +#define NH_HASH_BYTES (NH_NUM_PASSES * sizeof(u64)) + +/* Max message size: 1024 bytes (32x compression factor) */ +#define NH_NUM_STRIDES 64 +#define NH_MESSAGE_WORDS (NH_PAIR_STRIDE * 2 * NH_NUM_STRIDES) +#define NH_MESSAGE_BYTES (NH_MESSAGE_WORDS * sizeof(u32)) +#define NH_KEY_WORDS (NH_MESSAGE_WORDS + \ + NH_PAIR_STRIDE * 2 * (NH_NUM_PASSES - 1)) +#define NH_KEY_BYTES (NH_KEY_WORDS * sizeof(u32)) + +/** + * nh() - NH hash function for Adiantum + * @key: The key. @message_len + 48 bytes of it are used. This is NH_KEY_BYTES + * if @message_len has its maximum length of NH_MESSAGE_BYTES. + * @message: The message + * @message_len: The message length in bytes. Must be a multiple of 16 + * (NH_MESSAGE_UNIT) and at most 1024 (NH_MESSAGE_BYTES). + * @hash: (output) The resulting hash value + * + * Note: the pseudocode for NH in the Adiantum paper iterates over 1024-byte + * segments of the message, computes a 32-byte hash for each, and returns all + * the hashes concatenated together. In contrast, this function just hashes one + * segment and returns one hash. It's the caller's responsibility to call this + * function for each 1024-byte segment and collect all the hashes. + * + * Context: Any context. + */ +void nh(const u32 *key, const u8 *message, size_t message_len, + __le64 hash[NH_NUM_PASSES]); + +#endif /* _CRYPTO_NH_H */ -- cgit v1.3.1