src/main/java/cn/jiguang/common/utils/sm2/BCECUtil.java
public static ECPrivateKeyParameters convertSEC1ToECPrivateKey(byte[] sec1Key)
        throws NoSuchAlgorithmException, NoSuchProviderException, InvalidKeySpecException, IOException {
        BCECPrivateKey privateKey = convertSEC1ToBCECPrivateKey(sec1Key);
        return convertPrivateKeyToParameters(privateKey);
    }
public static ECPrivateKeyParameters convertSEC1ToECPrivateKey(byte[] sec1Key)
        throws NoSuchAlgorithmException, NoSuchProviderException, InvalidKeySpecException, IOException {
        BCECPrivateKey privateKey = convertSEC1ToBCECPrivateKey(sec1Key);
        return convertPrivateKeyToParameters(privateKey);
    }
将SEC1标准的私钥字节流转为ECPrivateKeyParameters对象
openssl i2d_ECPrivateKey函数生成的DER编码的ecc私钥是：SEC1标准的、带有EC_GROUP、带有公钥的，
这个工具函数的主要目的就是为了使Java程序能够“识别”openssl生成的ECC私钥

@param sec1Key
@return
@throws NoSuchAlgorithmException
@throws NoSuchProviderException
@throws InvalidKeySpecException