41 lines
1.2 KiB
C
41 lines
1.2 KiB
C
/*
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* HKDF-SHA3-256 (RFC 5869, with SHA3-256 as the hash)
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* SPDX-License-Identifier: AGPL-3.0-or-later
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*
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* SHA3-256 is preferred over SHA-256 here because Keccak's sponge
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* construction has stronger structural properties (no length-extension,
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* indifferentiable from a random oracle in the standard model).
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*/
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#ifndef ZSDK_HKDF_H
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#define ZSDK_HKDF_H
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#ifdef __cplusplus
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extern "C" {
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#endif
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#include <stddef.h>
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#include <stdint.h>
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#define ZSDK_HKDF_HASHLEN 32 /* SHA3-256 output size */
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/* HKDF-Extract: PRK = HMAC-SHA3-256(salt, IKM) */
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void zsdk_hkdf_extract(uint8_t prk[32],
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const uint8_t *salt, size_t salt_len,
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const uint8_t *ikm, size_t ikm_len);
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/* HKDF-Expand: produces `out_len` bytes (out_len <= 255 * 32). */
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int zsdk_hkdf_expand(uint8_t *out, size_t out_len,
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const uint8_t prk[32],
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const uint8_t *info, size_t info_len);
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/* Convenience: extract+expand in one call. */
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int zsdk_hkdf(uint8_t *out, size_t out_len,
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const uint8_t *salt, size_t salt_len,
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const uint8_t *ikm, size_t ikm_len,
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const uint8_t *info, size_t info_len);
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#ifdef __cplusplus
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}
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#endif
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#endif
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