CRYPTO_MEMCMP(3) Library Functions Manual CRYPTO_MEMCMP(3)
NAME
CRYPTO_memcmp — constant time memory comparison
SYNOPSIS
#include <openssl/crypto.h>
int
CRYPTO_memcmp(const void *a, const void *b, size_t len);
DESCRIPTION
CRYPTO_memcmp() compares the len bytes pointed to by a and b for equality. It takes an amount of time dependent on len, but independent of the contents of the memory regions pointed to by a and b.
RETURN VALUES
CRYPTO_memcmp() returns 0 if the content of the memory regions is equal or non-zero otherwise.
HISTORY
CRYPTO_memcmp() first appeared in OpenSSL 1.0.1d and has been available since OpenBSD 5.6.
BUGS
Unlike memcmp(3) and timingsafe_memcmp(3), this function cannot be used to order the two memory regions. In the current implementation, the return value is always greater than or equal to 0. GNU August 25, 2019 CRYPTO_MEMCMP(3)