added CMacWithIV class for "backwards" compatibility.

2 files changed, 45 insertions, 1 deletions

diff --git a/core/src/main/java/org/bouncycastle/crypto/macs/CMac.java b/core/src/main/java/org/bouncycastle/crypto/macs/CMac.java
index 64294e08..e4b2d7f3 100644
--- a/core/src/main/java/org/bouncycastle/crypto/macs/CMac.java
+++ b/core/src/main/java/org/bouncycastle/crypto/macs/CMac.java
@@ -142,7 +142,8 @@ public class CMac implements Mac
             cipher.processBlock(ZEROES, 0, L, 0);
             Lu = doubleLu(L);
             Lu2 = doubleLu(Lu);
-        } else if (params != null)
+        }
+        else if (params != null)
         {
             // CMAC mode does not permit IV to underlying CBC mode
             throw new IllegalArgumentException("CMac mode only permits key to be set.");
diff --git a/core/src/main/java/org/bouncycastle/crypto/macs/CMacWithIV.java b/core/src/main/java/org/bouncycastle/crypto/macs/CMacWithIV.java
new file mode 100644
index 00000000..8361eea0
--- /dev/null
+++ b/core/src/main/java/org/bouncycastle/crypto/macs/CMacWithIV.java
@@ -0,0 +1,43 @@
+package org.bouncycastle.crypto.macs;
+
+import org.bouncycastle.crypto.BlockCipher;
+import org.bouncycastle.crypto.CipherParameters;
+import org.bouncycastle.crypto.params.ParametersWithIV;
+
+/**
+ * A non-NIST variant which allows passing of an IV to the underlying CBC cipher.
+ * <p>Note: there isn't really a good reason to use an IV here, use the regular CMac where possible.</p>
+ */
+public class CMacWithIV
+    extends CMac
+{
+    private BlockCipher cipher;
+
+    public CMacWithIV(BlockCipher cipher)
+    {
+        super(cipher);
+        this.cipher = cipher;
+    }
+
+    public CMacWithIV(BlockCipher cipher, int macSizeInBits)
+    {
+        super(cipher, macSizeInBits);
+        this.cipher = cipher;
+    }
+
+    public void init(CipherParameters params)
+    {
+        if (params instanceof ParametersWithIV)
+        {
+            ParametersWithIV pWithIV = (ParametersWithIV)params;
+
+            super.init(pWithIV.getParameters());
+
+            cipher.init(true, params);
+        }
+        else
+        {
+            super.init(params);
+        }
+    }
+}