问题
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 toConfig.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.
回答1:
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);
来源:https://stackoverflow.com/questions/39749956/converting-hmac-sha1-from-node-js-to-java