From de2fc78ad125287a0428f9826440b9f09db9e56c Mon Sep 17 00:00:00 2001
From: catbref <misc-github@talk2dom.com>
Date: Mon, 2 Nov 2020 10:47:27 +0000
Subject: [PATCH] Add support for SHA256 digest of ByteBuffer in Crypto class

---
 src/main/java/org/qortal/crypto/Crypto.java | 22 +++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/src/main/java/org/qortal/crypto/Crypto.java b/src/main/java/org/qortal/crypto/Crypto.java
index a21ac594..49cdd2fb 100644
--- a/src/main/java/org/qortal/crypto/Crypto.java
+++ b/src/main/java/org/qortal/crypto/Crypto.java
@@ -1,5 +1,6 @@
 package org.qortal.crypto;
 
+import java.nio.ByteBuffer;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
 import java.util.Arrays;
@@ -42,6 +43,27 @@ public abstract class Crypto {
 		}
 	}
 
+	/**
+	 * Returns 32-byte SHA-256 digest of message passed in input.
+	 * 
+	 * @param input
+	 *            variable-length byte[] message
+	 * @return byte[32] digest, or null if SHA-256 algorithm can't be accessed
+	 */
+	public static byte[] digest(ByteBuffer input) {
+		if (input == null)
+			return null;
+
+		try {
+			// SHA2-256
+			MessageDigest sha256 = MessageDigest.getInstance("SHA-256");
+			sha256.update(input);
+			return sha256.digest();
+		} catch (NoSuchAlgorithmException e) {
+			throw new RuntimeException("SHA-256 message digest not available");
+		}
+	}
+
 	/**
 	 * Returns 32-byte digest of two rounds of SHA-256 on message passed in input.
 	 *