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/**
* wsgcrypt.c
*
* Created on 2020-11-26
* @author: qyc
*
* @explain:
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "wsgcrypt.h"
gcry_error_t ws_hmac_buffer(int algo, void *digest, const void *buffer, size_t length, const void *key, size_t keylen)
{
gcry_md_hd_t hmac_handle;
gcry_error_t result = gcry_md_open(&hmac_handle, algo, GCRY_MD_FLAG_HMAC);
if (result) {
return result;
}
result = gcry_md_setkey(hmac_handle, key, keylen);
if (result) {
gcry_md_close(hmac_handle);
return result;
}
gcry_md_write(hmac_handle, buffer, length);
memcpy(digest, gcry_md_read(hmac_handle, 0), gcry_md_get_algo_dlen(algo));
gcry_md_close(hmac_handle);
return GPG_ERR_NO_ERROR;
}
gcry_error_t hkdf_expand(int hashalgo, const guint8 *prk, guint prk_len, const guint8 *info, guint info_len, guint8 *out, guint out_len)
{
// Current maximum hash output size: 48 bytes for SHA-384.
guchar lastoutput[48];
gcry_md_hd_t h;
gcry_error_t err;
const guint hash_len = gcry_md_get_algo_dlen(hashalgo);
// Some sanity checks
if (!(out_len > 0 && out_len <= 255 * hash_len) || !(hash_len > 0 && hash_len <= sizeof(lastoutput)))
return GPG_ERR_INV_ARG;
err = gcry_md_open(&h, hashalgo, GCRY_MD_FLAG_HMAC);
if (err)
return err;
guint offset;
for (offset = 0; offset < out_len; offset += hash_len) {
gcry_md_reset(h);
// Set PRK
gcry_md_setkey(h, prk, prk_len);
if (offset > 0)
// T(1..N)
gcry_md_write(h, lastoutput, hash_len);
// info
gcry_md_write(h, info, info_len);
// constant 0x01..N
gcry_md_putc(h, (guint8)(offset / hash_len + 1));
memcpy(lastoutput, gcry_md_read(h, hashalgo), hash_len);
memcpy(out + offset, lastoutput, MIN(hash_len, out_len - offset));
}
gcry_md_close(h);
return 0;
}
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