Java Rsa 签名 验签

签名：

    private static final BouncyCastleProvider PROVIDER = new BouncyCastleProvider();

public static String sign(String content, PrivateKey privateKey) throws Exception{
        Signature signature = Signature.getInstance("SHA256withRSAandMGF1", PROVIDER);
        signature.initSign(privateKey);
        signature.update(content.getBytes("utf-8"));
        byte[] signed = signature.sign();
        return encodeBASE64(signed);
    }

    public static String encodeBASE64(byte[] bytes) throws Exception{
        //BASE64Encoder b64=new BASE64Encoder();
        //return b64.encode(bytes);
        Base64 b64=new Base64();
        String str=new String(b64.encodeBase64(bytes),"UTF8");
        return str;
    }

验签:

    private static final BouncyCastleProvider PROVIDER = new BouncyCastleProvider();

    public static boolean checkSign(String content, String sign, PublicKey publicKey, String signAlgorithm) throws Exception{
        Signature signature = Signature.getInstance("SHA256withRSAandMGF1", PROVIDER);
        signature.initVerify(publicKey);
        signature.update(content.getBytes("utf-8"));
        return signature.verify(decodeBASE64(sign));
    }

注意：签名验签时候的签名算法要统一，此処的算法為sha256