HASH_REG_SIZEOF
#define HASH_MD5_MAX_REG (MD5_DIGEST_SIZE / HASH_REG_SIZEOF)
#define HASH_SHA1_MAX_REG (SHA1_DIGEST_SIZE / HASH_REG_SIZEOF)
#define HASH_SHA256_MAX_REG (SHA256_DIGEST_SIZE / HASH_REG_SIZEOF)
memcpy(req->result, ctx->digest, ctx->nregs * HASH_REG_SIZEOF);