如何在Android中计算字符串的SHA-256哈希值？

Question

我想在Android中获取字符串的SHA256.

这是我要匹配的PHP代码:

echo bin2hex(mhash(MHASH_SHA256,"asdf"));
//outputs "f0e4c2f76c58916ec258f246851bea091d14d4247a2fc3e18694461b1816e13b"

现在,在Java中,我正在尝试执行以下操作:

            String password="asdf"
            MessageDigest digest=null;
    try {
        digest = MessageDigest.getInstance("SHA-256");
    } catch (NoSuchAlgorithmException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
       digest.reset();
       try {
        Log.i("Eamorr",digest.digest(password.getBytes("UTF-8")).toString());
    } catch (UnsupportedEncodingException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

但这打印出来:"a42yzk3axdv3k4yh98g8"

我在这做错了什么？

---

解决方案感谢erickson:

 Log.i("Eamorr",bin2hex(getHash("asdf")));

 public byte[] getHash(String password) {
       MessageDigest digest=null;
    try {
        digest = MessageDigest.getInstance("SHA-256");
    } catch (NoSuchAlgorithmException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }
       digest.reset();
       return digest.digest(password.getBytes());
 }
static String bin2hex(byte[] data) {
    return String.format("%0" + (data.length*2) + "X", new BigInteger(1, data));
}

Answer 1

PHP函数bin2hex意味着它需要一个字节串并将其编码为十六进制数.

在Java代码中,您尝试使用平台的默认字符编码来获取一堆随机字节并将其解码为字符串.这不会起作用,如果确实如此,它将不会产生相同的结果.

这是Java的快速而又脏的二进制到十六进制转换:

static String bin2hex(byte[] data) {
    StringBuilder hex = new StringBuilder(data.length * 2);
    for (byte b : data)
        hex.append(String.format("%02x", b & 0xFF));
    return hex.toString();
}

这很快写,不一定快速执行.如果你正在做很多这些,你应该用更快的实现重写函数.

Answer 2

你是沿着正确的路线,但转换字节有点复杂.这适用于我的设备:

// utility function
    private static String bytesToHexString(byte[] bytes) {
        // http://stackoverflow.com/questions/332079
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < bytes.length; i++) {
            String hex = Integer.toHexString(0xFF & bytes[i]);
            if (hex.length() == 1) {
                sb.append('0');
            }
            sb.append(hex);
        }
        return sb.toString();
    }

// generate a hash

    String password="asdf";
    MessageDigest digest=null;
    String hash;
    try {
        digest = MessageDigest.getInstance("SHA-256");
        digest.update(password.getBytes());

        hash = bytesToHexString(digest.digest());

        Log.i("Eamorr", "result is " + hash);
    } catch (NoSuchAlgorithmException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }

来源:bytesToHexString函数来自IOSched项目.

Answer 3

通过使用示例完成答案，感谢埃里克森。

public static String getSha256Hash(String password) {
    try {
        MessageDigest digest = null;
        try {
            digest = MessageDigest.getInstance("SHA-256");
        } catch (NoSuchAlgorithmException e1) {
            e1.printStackTrace();
        }
        digest.reset();
        return bin2hex(digest.digest(password.getBytes()));
    } catch (Exception ignored) {
        return null;
    }
}

private static String bin2hex(byte[] data) {
    StringBuilder hex = new StringBuilder(data.length * 2);
    for (byte b : data)
        hex.append(String.format("%02x", b & 0xFF));
    return hex.toString();
}

使用示例：

Toast.makeText(this, Utils.getSha256Hash("123456_MY_PASSWORD"), Toast.LENGTH_SHORT).show();