public static PrivateKey readPemPrivateKey(InputStream pemStream) {
		return (PrivateKey) readPemKey(pemStream);
	}
@Test
	public void readECPrivateKeyTest() {
		final PrivateKey privateKey = PemUtil.readPemPrivateKey(ResourceUtil.getStream("test_ec_sec1_private_key.pem"));
		final SM2 sm2 = new SM2(privateKey, null);
		sm2.usePlainEncoding();

		//需要签名的明文,得到明文对应的字节数组
		final byte[] dataBytes = "我是一段测试aaaa".getBytes(StandardCharsets.UTF_8);

		final byte[] sign = sm2.sign(dataBytes, null);
		// 64位签名
		assertEquals(64, sign.length);
	}