RSA签名报错

这是签名的方法

public static String Sign2(String data, String BEISEN_PRIKEY) throws Exception {
        // 密钥格式为PKCS1 需要转换为PKCS8才可以使用
        byte[] encodeByte = Base64.decodeBase64(BEISEN_PRIKEY);
        AlgorithmIdentifier algorithmIdentifier = new AlgorithmIdentifier(PKCSObjectIdentifiers.pkcs8ShroudedKeyBag);    //PKCSObjectIdentifiers.pkcs8ShroudedKeyBag
        ASN1Object asn1Object = ASN1Object.fromByteArray(encodeByte);
        PrivateKeyInfo privKeyInfo = new PrivateKeyInfo(algorithmIdentifier, asn1Object);
        byte[] pkcs8Bytes = privKeyInfo.getEncoded();

        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(pkcs8Bytes);
        KeyFactory keyFactory = KeyFactory.getInstance("RSA","BC");
        PrivateKey key = keyFactory.generatePrivate(keySpec);
        Signature signature = Signature.getInstance(SIGN_ALGORITHMS);
        signature.initSign(key);
        signature.update(data.getBytes(encoding));
        return new String(Base64.encodeBase64(signature.sign()));
    }





然后控制台报了这个错


java.security.spec.InvalidKeySpecException: java.lang.ClassCastException: org.bouncycastle.asn1.DERSequence cannot be cast to org.bouncycastle.asn1.DERInteger


这个要怎么改的