/** * DSA verify * * @param string $message message * @param string $hash_alg hash algorithm * @param MathBigInteger $r r * @param MathBigInteger $s s * @param MathBigInteger $p p * @param MathBigInteger $q q * @param MathBigInteger $g g * @param MathBigInteger $y public key * @return bool */ public static function verify($message, $hash_alg, $r, $s, $p, $q, $g, $y) { $hash = new CryptHash($hash_alg); $hash_m = new MathBigInteger($hash->hash($message), 256); $w = $s->modInverse($q); $hash_m_mul = $hash_m->multiply($w); $u1_base = $hash_m_mul->divide($q); $u1 = $u1_base[1]; $r_mul = $r->multiply($w); $u2_base = $r_mul->divide($q); $u2 = $u2_base[1]; $g_pow = $g->modPow($u1, $p); $y_pow = $y->modPow($u2, $p); $g_pow_mul = $g_pow->multiply($y_pow); $g_pow_mul_mod_base = $g_pow_mul->divide($p); $g_pow_mul_mod = $g_pow_mul_mod_base[1]; $v_base = $g_pow_mul_mod->divide($q); $v = $v_base[1]; return $v->compare($r) == 0; }