在Android/Java和C#中计算SHA256哈希

Question

我试图在android中生成SHA256哈希,然后我传递给ASP.NET Web API Web服务并在那里比较哈希.因此,我需要在Android中构造一个哈希,给定ASP.NET中相同的输入将生成一个等效的哈希.我拉着我的头发试图找出我做错了什么.

这是Android代码:

public String computeHash(String input) throws NoSuchAlgorithmException{
    MessageDigest digest = MessageDigest.getInstance("SHA-256");
    digest.reset();
    try{
      digest.update(input.getBytes("UTF-8"));
    } catch (UnsupportedEncodingException e){
      e.printStackTrace();
    }

    byte[] byteData = digest.digest(input.getBytes());
    StringBuffer sb = new StringBuffer();

    for (int i = 0; i < byteData.length; i++){
      sb.append(Integer.toString((byteData[i] & 0xff) + 0x100, 16).substring(1));
    }
    return sb.toString();
}

以及这里的服务器代码(c#):

    private static string ComputeHash(string input, HashAlgorithm algorithm)
    {

        Byte[] inputBytes = Encoding.UTF8.GetBytes(input);
        Byte[] hashedBytes = algorithm.ComputeHash(inputBytes);

        StringBuilder sb = new StringBuilder();

        for (int i = 0; i < hashedBytes.Length; i++)
        {
            sb.Append(String.Format("{0:x2}", hashedBytes[i]));
        }

        return sb.ToString();
    }

更新: 这是更正的Android/Java实现(谢谢Nikolay Elenkov):

public String computeHash(String input) throws NoSuchAlgorithmException, UnsupportedEncodingException{
    MessageDigest digest = MessageDigest.getInstance("SHA-256");
    digest.reset();

    byte[] byteData = digest.digest(input.getBytes("UTF-8"));
    StringBuffer sb = new StringBuffer();

    for (int i = 0; i < byteData.length; i++){
      sb.append(Integer.toString((byteData[i] & 0xff) + 0x100, 16).substring(1));
    }
    return sb.toString();
}

Answer 1

您的Java代码错误:您要添加两次输入字节.如果你是在一个去计算这个,你只需要透过电话digest(bytes)或呼叫digest()后update(bytes);