From bd6dee5376a91b36803e1b797f86ac72fb49bc9d Mon Sep 17 00:00:00 2001
From: sharifi <h_sharifi@modernisc.com>
Date: Mon, 1 Nov 2021 11:01:44 +0330
Subject: [PATCH] bael-4604: add main class

---
 .../main/java/com/baeldung/hmac/HMACUtil.java | 68 +++++++++++++++++++
 1 file changed, 68 insertions(+)
 create mode 100644 core-java-modules/core-java-security-3/src/main/java/com/baeldung/hmac/HMACUtil.java

diff --git a/core-java-modules/core-java-security-3/src/main/java/com/baeldung/hmac/HMACUtil.java b/core-java-modules/core-java-security-3/src/main/java/com/baeldung/hmac/HMACUtil.java
new file mode 100644
index 0000000000..3b504d9338
--- /dev/null
+++ b/core-java-modules/core-java-security-3/src/main/java/com/baeldung/hmac/HMACUtil.java
@@ -0,0 +1,68 @@
+package com.baeldung.hmac;
+
+import org.apache.commons.codec.digest.HmacUtils;
+import org.bouncycastle.crypto.Digest;
+import org.bouncycastle.crypto.digests.MD5Digest;
+import org.bouncycastle.crypto.digests.SHA256Digest;
+import org.bouncycastle.crypto.digests.SHA384Digest;
+import org.bouncycastle.crypto.digests.SHA512Digest;
+import org.bouncycastle.crypto.macs.HMac;
+import org.bouncycastle.crypto.params.KeyParameter;
+
+import javax.crypto.Mac;
+import javax.crypto.spec.SecretKeySpec;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+
+
+public class HMACUtil {
+
+    public static String hmacWithJava(String algorithm, String data, String key)
+        throws NoSuchAlgorithmException, InvalidKeyException {
+        SecretKeySpec secretKeySpec = new SecretKeySpec(key.getBytes(), algorithm);
+        Mac mac = Mac.getInstance(algorithm);
+        mac.init(secretKeySpec);
+        return bytesToHex(mac.doFinal(data.getBytes()));
+    }
+
+    public static String hmacWithApacheCommons(String algorithm, String data, String key) {
+        String hmac = new HmacUtils(algorithm, key).hmacHex(data);
+        return hmac;
+    }
+
+    public static String hmacWithBouncyCastle(String algorithm, String data, String key) {
+        Digest digest = getHashDigest(algorithm);
+        HMac hMac = new HMac(digest);
+        hMac.init(new KeyParameter(key.getBytes()));
+        byte[] hmacIn = data.getBytes();
+        hMac.update(hmacIn, 0, hmacIn.length);
+        byte[] hmacOut = new byte[hMac.getMacSize()];
+        hMac.doFinal(hmacOut, 0);
+        return bytesToHex(hmacOut);
+    }
+
+    private static Digest getHashDigest(String algorithm) {
+        switch (algorithm) {
+          case "HmacMD5":
+            return new MD5Digest();
+          case "HmacSHA256":
+            return new SHA256Digest();
+          case "HmacSHA384":
+            return new SHA384Digest();
+          case "HmacSHA512":
+            return new SHA512Digest();
+        }
+        return new SHA256Digest();
+    }
+
+    public static String bytesToHex(byte[] hash) {
+        StringBuilder hexString = new StringBuilder(2 * hash.length);
+        for (byte h : hash) {
+          String hex = Integer.toHexString(0xff & h);
+          if (hex.length() == 1)
+            hexString.append('0');
+          hexString.append(hex);
+        }
+        return hexString.toString();
+    }
+}