bool hashlib_SSLVerifySignature(const uint8_t *ca_pubkey, size_t keysize, const uint8_t *cert, size_t certlen, uint8_t sig_alg){
	if((ca_pubkey == NULL) || (cert == NULL)) return false;
    if(certlen <= keysize) return false;
	switch(sig_alg){
		case RSA_SHA256:
		{
            uint8_t sig_buf[RSA_MODULUS_MAX];
			uint8_t sha256digest[32];
			SHA256_CTX ctx;
			uint8_t mbuffer[64*4];
            memcpy(sig_buf, &cert[certlen-keysize-1], keysize);
			hashlib_RSAEncrypt(sig_buf, keysize, ca_pubkey, keysize);
			hashlib_Sha256Init(&ctx, mbuffer);
			hashlib_Sha256Update(&ctx, cert, certlen-keysize);
			hashlib_Sha256Final(&ctx, sha256digest);
            return hashlib_RSAVerifyPSS(sha256digest, 32, sig_buf, keysize);
			break;
		}
		default:
			return false;
	}
}