Go SHA-256哈希与Java SHA-256哈希不同

Question

If I generate the SHA-256 hash in the language "GO", I get a different byte-Array compared to the Java equivalent.

This is the GO version:

fmt.Println(getSha256([]byte("5nonce=5")))

The resulting array looks like:

41 79 186 235 199 123 95 226 16 59 51 161 112 245 192 50 21 66 180 250 179 109 153 18 233 148 16 237 156 69 163 150]

This one should do the same in Java code:

MessageDigest md = MessageDigest.getInstance("SHA-256");

md.update("5nonce=5".getBytes()); 
byte[] digest = md.digest();

But results in this byte array

[41, 79, -70, -21, -57, 123, 95, -30, 16, 59, 51, -95, 112, -11, -64, 50, 21, 66, -76, -6, -77, 109, -103, 18, -23, -108, 16, -19, -100, 69, -93, -106]

Why are they different? How do I need to change the java version to work exactly like the Go version?

Answer 1

Why are they different?

They're not, really. They're the same bits. It's just that Java doesn't have unsigned bytes - so any byte with the top bit set is negative. In every case like that, you'll see that Java result = Go result - 256.

If you convert both byte arrays to hex or base64, you'll see same results.