Java数字签名与C＃不同

Question

I have the following c# code to generate a digital signature from a private key:

    static string Sign(string text, string certificate)
    {

        X509Certificate2 cert = new X509Certificate2(certificate, "TestPassword", X509KeyStorageFlags.Exportable);
        RSACryptoServiceProvider rsa = (RSACryptoServiceProvider)cert.PrivateKey;
        // Hash the data
        SHA1Managed sha1 = new SHA1Managed();
        ASCIIEncoding encoding = new ASCIIEncoding();
        byte[] data = encoding.GetBytes(text);
        byte[] hash = sha1.ComputeHash(data);
        // Sign the hash
        return System.Convert.ToBase64String(rsa.SignHash(hash, CryptoConfig.MapNameToOID("SHA1")));            
    }

I then created what I thought was the equivalent java code:

public static String signData(String dataToSign, String keyFile) { 
  FileInputStream keyfis = null;
  try {
    keyfis = new FileInputStream(fileName);
    KeyStore store = KeyStore.getInstance("PKCS12");
    store.load(keyfis, "TestPassword".toCharArray());
    KeyStore.PrivateKeyEntry pvk = (KeyStore.PrivateKeyEntry)store.
          getEntry("testkey", 
          new KeyStore.PasswordProtection("TestPassword".toCharArray()));
    PrivateKey privateKey = (PrivateKey)pvk.getPrivateKey();
    byte[] data = dataToSign.getBytes("US-ASCII");
    MessageDigest md = MessageDigest.getInstance("SHA1");
    byte[] hashed = md.digest(data);
    Signature rsa = Signature.getInstance("SHA1withRSA");
    rsa.initSign(privateKey);
    rsa.update(data);
    return Base64.encode(rsa.sign());
  } catch (Exception ex) {
    Logger.getLogger(this.getClass().getName()).log(Level.SEVERE, null, ex);
  } finally {
    if ( keyfis != null ) {
      try { keyfis.close() } catch (Exception ex) { keyfis = null; }
    }
  }
  return null;
}

Unfortunately the digital signatures do not match.

Any assistance will be greatly appreciated. Thanks in advance.

EDIT : If I remove the MessageDigest from the java code then the output is the same. Why? I thought hashing is needed.

Regards, Eugene

Answer 1

Ok so I have confirmed it. If I remove the MessageDigest/Hashing code from the java sample code then the two digital signatures are the same. Not sure why, but I'll try and find out. If anyone would like to educate me further feel free.

Answer 2

Java符号方法基于Signature类的getInstance方法中提供的算法进行散列和签名，因此基本上您在Java中进行了两次哈希处理。