When I reproduce a SHA2 hash via the following code:
MessageDigest digest = MessageDigest.getInstance("SHA-256");
digest.digest("A".getBytes("UTF-8"));
it gives me a byte array, which is: 85,-102,-22,-48,-126,100,-43,121,93,57,9,113,-116,-35,5,-85,-44,-107,114,-24,79,-27,85,-112,-18,-13,26,-120,-96,-113,-33,-3
But when I reproduce same hash via MySQL it gives me a string which is: 5cfe2cddbb9940fb4d8505e25ea77e763a0077693dbb01b1a6aa94f2
How can I convert tha Java's result so that I can compare it with MySQL's result?
First check out your DB result it looks like your initial hash is actually a SHA-224 not SHA-256:
mysql> SELECT SHA2("A", 224);
+----------------------------------------------------------+
| SHA2("A", 224) |
+----------------------------------------------------------+
| 5cfe2cddbb9940fb4d8505e25ea77e763a0077693dbb01b1a6aa94f2 |
+----------------------------------------------------------+
1 row in set (0.00 sec)
Instead of:
mysql> SELECT SHA2("A", 256);
+------------------------------------------------------------------+
| SHA2("A", 256) |
+------------------------------------------------------------------+
| 559aead08264d5795d3909718cdd05abd49572e84fe55590eef31a88a08fdffd |
+------------------------------------------------------------------+
1 row in set (0.06 sec)
From there you're on the right track you just need to convert the byte[] output to a hex string.
import java.security.MessageDigest;
public class TestSHA256 {
public static void main(String[] args) {
try {
MessageDigest digest = MessageDigest.getInstance("SHA-256");
byte[] hash = digest.digest("A".getBytes("UTF-8"));
StringBuilder hexString = new StringBuilder();
for (int i: hash) {
hexString.append(Integer.toHexString(0XFF & i));
}
System.out.println(hexString);
} catch (Exception e) {
e.printStackTrace();
}
}
}
Output:
559aead08264d5795d399718cdd5abd49572e84fe55590eef31a88a08fdffd
Integer.toHexString(0XFF & i) must be replaced with String.format("%02x", 0XFF & i), otherwise it only produces a 1 character output, while 2 characters are expected.
