mirror of
https://github.com/bol-van/zapret.git
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338 lines
9.7 KiB
C
338 lines
9.7 KiB
C
/**************************** hkdf.c ***************************/
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/***************** See RFC 6234 for details. *******************/
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/* Copyright (c) 2011 IETF Trust and the persons identified as */
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/* authors of the code. All rights reserved. */
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/* See sha.h for terms of use and redistribution. */
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/*
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* Description:
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* This file implements the HKDF algorithm (HMAC-based
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* Extract-and-Expand Key Derivation Function, RFC 5869),
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* expressed in terms of the various SHA algorithms.
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*/
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#include "sha.h"
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#include <string.h>
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#include <stdlib.h>
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/*
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* hkdf
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*
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* Description:
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* This function will generate keying material using HKDF.
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*
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* Parameters:
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* whichSha: [in]
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* One of SHA1, SHA224, SHA256, SHA384, SHA512
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* salt[ ]: [in]
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* The optional salt value (a non-secret random value);
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* if not provided (salt == NULL), it is set internally
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* to a string of HashLen(whichSha) zeros.
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* salt_len: [in]
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* The length of the salt value. (Ignored if salt == NULL.)
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* ikm[ ]: [in]
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* Input keying material.
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* ikm_len: [in]
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* The length of the input keying material.
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* info[ ]: [in]
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* The optional context and application specific information.
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* If info == NULL or a zero-length string, it is ignored.
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* info_len: [in]
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* The length of the optional context and application specific
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* information. (Ignored if info == NULL.)
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* okm[ ]: [out]
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* Where the HKDF is to be stored.
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* okm_len: [in]
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* The length of the buffer to hold okm.
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* okm_len must be <= 255 * USHABlockSize(whichSha)
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*
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* Notes:
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* Calls hkdfExtract() and hkdfExpand().
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*
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* Returns:
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* sha Error Code.
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*
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*/
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int hkdf(SHAversion whichSha,
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const unsigned char *salt, size_t salt_len,
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const unsigned char *ikm, size_t ikm_len,
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const unsigned char *info, size_t info_len,
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uint8_t okm[], size_t okm_len)
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{
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uint8_t prk[USHAMaxHashSize];
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return hkdfExtract(whichSha, salt, salt_len, ikm, ikm_len, prk) ||
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hkdfExpand(whichSha, prk, USHAHashSize(whichSha), info,
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info_len, okm, okm_len);
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}
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/*
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* hkdfExtract
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*
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* Description:
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* This function will perform HKDF extraction.
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*
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* Parameters:
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* whichSha: [in]
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* One of SHA1, SHA224, SHA256, SHA384, SHA512
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* salt[ ]: [in]
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* The optional salt value (a non-secret random value);
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* if not provided (salt == NULL), it is set internally
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* to a string of HashLen(whichSha) zeros.
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* salt_len: [in]
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* The length of the salt value. (Ignored if salt == NULL.)
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* ikm[ ]: [in]
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* Input keying material.
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* ikm_len: [in]
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* The length of the input keying material.
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* prk[ ]: [out]
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* Array where the HKDF extraction is to be stored.
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* Must be larger than USHAHashSize(whichSha);
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*
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* Returns:
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* sha Error Code.
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*
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*/
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int hkdfExtract(SHAversion whichSha,
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const unsigned char *salt, size_t salt_len,
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const unsigned char *ikm, size_t ikm_len,
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uint8_t prk[USHAMaxHashSize])
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{
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unsigned char nullSalt[USHAMaxHashSize];
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if (salt == 0) {
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salt = nullSalt;
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salt_len = USHAHashSize(whichSha);
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memset(nullSalt, '\0', salt_len);
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}
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else if (salt_len < 0) {
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return shaBadParam;
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}
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return hmac(whichSha, ikm, ikm_len, salt, salt_len, prk);
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}
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/*
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* hkdfExpand
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*
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* Description:
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* This function will perform HKDF expansion.
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*
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* Parameters:
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* whichSha: [in]
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* One of SHA1, SHA224, SHA256, SHA384, SHA512
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* prk[ ]: [in]
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* The pseudo-random key to be expanded; either obtained
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* directly from a cryptographically strong, uniformly
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* distributed pseudo-random number generator, or as the
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* output from hkdfExtract().
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* prk_len: [in]
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* The length of the pseudo-random key in prk;
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* should at least be equal to USHAHashSize(whichSHA).
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* info[ ]: [in]
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* The optional context and application specific information.
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* If info == NULL or a zero-length string, it is ignored.
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* info_len: [in]
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* The length of the optional context and application specific
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* information. (Ignored if info == NULL.)
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* okm[ ]: [out]
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* Where the HKDF is to be stored.
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* okm_len: [in]
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* The length of the buffer to hold okm.
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* okm_len must be <= 255 * USHABlockSize(whichSha)
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*
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* Returns:
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* sha Error Code.
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*
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*/
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int hkdfExpand(SHAversion whichSha, const uint8_t prk[], size_t prk_len,
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const unsigned char *info, size_t info_len,
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uint8_t okm[], size_t okm_len)
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{
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size_t hash_len, N;
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unsigned char T[USHAMaxHashSize];
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size_t Tlen, where, i;
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if (info == 0) {
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info = (const unsigned char *)"";
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info_len = 0;
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}
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else if (info_len < 0) {
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return shaBadParam;
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}
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if (okm_len <= 0) return shaBadParam;
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if (!okm) return shaBadParam;
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hash_len = USHAHashSize(whichSha);
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if (prk_len < hash_len) return shaBadParam;
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N = okm_len / hash_len;
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if ((okm_len % hash_len) != 0) N++;
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if (N > 255) return shaBadParam;
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Tlen = 0;
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where = 0;
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for (i = 1; i <= N; i++) {
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HMACContext context;
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unsigned char c = i;
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int ret = hmacReset(&context, whichSha, prk, prk_len) ||
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hmacInput(&context, T, Tlen) ||
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hmacInput(&context, info, info_len) ||
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hmacInput(&context, &c, 1) ||
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hmacResult(&context, T);
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if (ret != shaSuccess) return ret;
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memcpy(okm + where, T,
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(i != N) ? hash_len : (okm_len - where));
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where += hash_len;
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Tlen = hash_len;
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}
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return shaSuccess;
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}
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/*
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* hkdfReset
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*
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* Description:
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* This function will initialize the hkdfContext in preparation
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* for key derivation using the modular HKDF interface for
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* arbitrary length inputs.
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*
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* Parameters:
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* context: [in/out]
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* The context to reset.
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* whichSha: [in]
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* One of SHA1, SHA224, SHA256, SHA384, SHA512
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* salt[ ]: [in]
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* The optional salt value (a non-secret random value);
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* if not provided (salt == NULL), it is set internally
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* to a string of HashLen(whichSha) zeros.
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* salt_len: [in]
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* The length of the salt value. (Ignored if salt == NULL.)
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*
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* Returns:
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* sha Error Code.
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*
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*/
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int hkdfReset(HKDFContext *context, enum SHAversion whichSha,
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const unsigned char *salt, size_t salt_len)
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{
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unsigned char nullSalt[USHAMaxHashSize];
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if (!context) return shaNull;
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context->whichSha = whichSha;
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context->hashSize = USHAHashSize(whichSha);
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if (salt == 0) {
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salt = nullSalt;
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salt_len = context->hashSize;
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memset(nullSalt, '\0', salt_len);
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}
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return hmacReset(&context->hmacContext, whichSha, salt, salt_len);
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}
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/*
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* hkdfInput
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*
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* Description:
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* This function accepts an array of octets as the next portion
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* of the input keying material. It may be called multiple times.
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*
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* Parameters:
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* context: [in/out]
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* The HKDF context to update.
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* ikm[ ]: [in]
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* An array of octets representing the next portion of
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* the input keying material.
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* ikm_len: [in]
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* The length of ikm.
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*
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* Returns:
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* sha Error Code.
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*
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*/
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int hkdfInput(HKDFContext *context, const unsigned char *ikm,
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size_t ikm_len)
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{
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if (!context) return shaNull;
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if (context->Corrupted) return context->Corrupted;
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if (context->Computed) return context->Corrupted = shaStateError;
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return hmacInput(&context->hmacContext, ikm, ikm_len);
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}
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/*
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* hkdfFinalBits
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*
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* Description:
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* This function will add in any final bits of the
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* input keying material.
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*
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* Parameters:
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* context: [in/out]
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* The HKDF context to update
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* ikm_bits: [in]
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* The final bits of the input keying material, in the upper
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* portion of the byte. (Use 0b###00000 instead of 0b00000###
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* to input the three bits ###.)
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* ikm_bit_count: [in]
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* The number of bits in message_bits, between 1 and 7.
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*
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* Returns:
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* sha Error Code.
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*/
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int hkdfFinalBits(HKDFContext *context, uint8_t ikm_bits,
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unsigned int ikm_bit_count)
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{
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if (!context) return shaNull;
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if (context->Corrupted) return context->Corrupted;
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if (context->Computed) return context->Corrupted = shaStateError;
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return hmacFinalBits(&context->hmacContext, ikm_bits, ikm_bit_count);
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}
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/*
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* hkdfResult
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*
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* Description:
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* This function will finish the HKDF extraction and perform the
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* final HKDF expansion.
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*
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* Parameters:
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* context: [in/out]
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* The HKDF context to use to calculate the HKDF hash.
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* prk[ ]: [out]
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* An optional location to store the HKDF extraction.
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* Either NULL, or pointer to a buffer that must be
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* larger than USHAHashSize(whichSha);
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* info[ ]: [in]
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* The optional context and application specific information.
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* If info == NULL or a zero-length string, it is ignored.
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* info_len: [in]
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* The length of the optional context and application specific
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* information. (Ignored if info == NULL.)
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* okm[ ]: [out]
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* Where the HKDF is to be stored.
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* okm_len: [in]
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* The length of the buffer to hold okm.
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* okm_len must be <= 255 * USHABlockSize(whichSha)
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*
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* Returns:
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* sha Error Code.
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*
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*/
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int hkdfResult(HKDFContext *context,
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uint8_t prk[USHAMaxHashSize],
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const unsigned char *info, size_t info_len,
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uint8_t okm[], size_t okm_len)
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{
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uint8_t prkbuf[USHAMaxHashSize];
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int ret;
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if (!context) return shaNull;
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if (context->Corrupted) return context->Corrupted;
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if (context->Computed) return context->Corrupted = shaStateError;
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if (!okm) return context->Corrupted = shaBadParam;
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if (!prk) prk = prkbuf;
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ret = hmacResult(&context->hmacContext, prk) ||
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hkdfExpand(context->whichSha, prk, context->hashSize, info,
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info_len, okm, okm_len);
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context->Computed = 1;
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return context->Corrupted = ret;
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}
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