将HMAC-SHA1从node.js转换为Java [英] Converting HMAC-SHA1 from node.js to Java

问题描述

我的任务是将一些现有的node.js代码转换为Java。我觉得我很顺利，但现在我有点卡住了。方法的输出似乎不匹配。

我正在做的是根据查询字符串创建SHA-1签名。此查询字符串包含一些与查询相关的数据（与此问题无关）和API密钥。

重要

• node.js中的 api_secret 字符串相当于 Config.API_SECRET in Java。


• 示例查询字符串（在node.js和Java程序中它们相同）：
  
  / events？festival = imaginate& pretty = 1& size = 100& from = 0& key = SOME_KEY

实际代码

SHA-1 hmac在nodejs中初始化如下：

  const hmac = crypto.createHmac（'sha1'，api_secret）; 
  

SHA-1 mac在Java中初始化如下：

  final SecretKeySpec secretKeySpec = new SecretKeySpec（Config.API_SECRET.getBytes（UTF-8），HmacSHA1）; 
 final Mac hmac = Mac.getInstance（HmacSHA1）; 
 hmac.init（secretKeySpec）; 
  

接下来，node.js程序更新hmac（ query 参数如上所列）：

  hmac.update（query，'ascii'）; 
  

我在Java中复制的是这样的（查询参数等于node.js 查询参数）：

  hmac.update（query.getBytes（ US-ASCII））; 
  

最后，在node.js程序中将字节字符串转换为SHA-1哈希：

  const signature = hmac.digest（'hex'）; 
  

我找不到Java的确切翻译，但这是我的尝试，我认为关于同样的事情：

字节数组到十六进制函数

  public static String byteArrayToHex（byte [] a）{
 StringBuilder sb = new StringBuilder（a.length * 2）; 
 for（byte b：a）
 sb.append（String.format（％02x，b& 0xff））; 
返回sb.toString（）; 
} 
  

实际使用情况

  byte [] result = hmac.doFinal（）; 
 MessageDigest md = MessageDigest.getInstance（SHA-1）; 
 String sha1Hash = byteArrayToHex（md.digest（result））; 
  

然而，这是我感到困惑的地方。 node.js程序返回此哈希值：
18cf4fce7bd6163c64d3b2ea8d935b0f16720fe3

但我的Java程序将此哈希值作为输出：
f65f8738cce89134dc73709e3353d94c83ccf1fb

我无法弄清楚我哪里出错了，我真的希望有人可以说清楚这一点。

解决方案

我想通了！

<事实证明我正在做一个不必要的步骤。

这一行：

  byte [] result = mac.doFinal （）; 
  

已包含签名哈希。我需要将该字节数组转换为十六进制字符串，而不是该字节数组的摘要。

所以工作代码只是：

  byte [] result = mac.doFinal（）; 
返回byteArrayToHex（result）; 
  

I have been tasked with converting some existing piece of node.js code to Java. I think I'm well on my way, but I'm kind of stuck right now. The output of the methods do not seem to match.

What I'm doing is creating a SHA-1 signature based on a query string. This query string contains some query-related data (not relevant for this question) and an API key.

Important

• The api_secret string in node.js is equivalent to Config.API_SECRET in Java.
• Example query string (these are equal in the node.js and Java program):
  /events?festival=imaginate&pretty=1&size=100&from=0&key=SOME_KEY

Actual code

The SHA-1 hmac is initialized as follows in nodejs:

const hmac = crypto.createHmac('sha1', api_secret);

The SHA-1 mac is initialized as follows in Java:

final SecretKeySpec secretKeySpec = new SecretKeySpec(Config.API_SECRET.getBytes("UTF-8"), "HmacSHA1");
final Mac hmac = Mac.getInstance("HmacSHA1");
hmac.init(secretKeySpec);

Next, the node.js program updates the hmac as such (query parameter is as listed above):

hmac.update(query, 'ascii');

Which I replicated in Java like this (query parameter is equal to the node.js query parameter):

hmac.update(query.getBytes("US-ASCII"));

Finally, the byte string is converted to a SHA-1 hash as such in the node.js program:

const signature = hmac.digest('hex');

I couldn't find an exact translation to Java, but this was my attempt, which I think does about the same thing:

Byte array to hex function

public static String byteArrayToHex(byte[] a) {
    StringBuilder sb = new StringBuilder(a.length * 2);
    for(byte b: a)
        sb.append(String.format("%02x", b & 0xff));
    return sb.toString();
}

Actual usage

byte[] result = hmac.doFinal();
MessageDigest md = MessageDigest.getInstance("SHA-1");
String sha1Hash = byteArrayToHex(md.digest(result));

However, this is where I get confused. The node.js program returns this hash: 18cf4fce7bd6163c64d3b2ea8d935b0f16720fe3

But my Java program gives this hash as output: f65f8738cce89134dc73709e3353d94c83ccf1fb

I can't figure out where I went wrong and I really hope someone could shed a light on this.

解决方案

I figured it out!

Turns out I was doing one unnecessary step.

This line:

byte[] result = mac.doFinal();

Already contained the signature hash. I needed to convert that byte array to a hex string, not the digest of that byte array.

So the working code was simply:

byte[] result = mac.doFinal();
return byteArrayToHex(result);

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