--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dcrypt/crypto/padding/PKCS7.d	Sun Aug 10 14:20:17 2008 -0400
@@ -0,0 +1,50 @@
+/**
+ * This file is part of the dcrypt project.
+ *
+ * Copyright: Copyright (C) dcrypt contributors 2008. All rights reserved.
+ * License:   MIT
+ * Authors:   Thomas Dixon
+ */
+
+module dcrypt.crypto.padding.PKCS7;
+
+import dcrypt.crypto.BlockCipherPadding; 
+
+/**
+ * This class implements the padding scheme described in PKCS7
+ * from RSA Security. Ex. [... 0x03, 0x03, 0x03]
+ */
+class PKCS7 : BlockCipherPadding {
+    char[] name() {
+        return "PKCS7";   
+    }
+    
+    /* Assumes input_ is a multiple of the underlying
+     * block cipher's block size.
+     */
+    uint padBlock(void[] input_, uint inOff) {
+        ubyte[] input = cast(ubyte[]) input_;
+
+        ubyte len = (input.length - inOff);
+        
+        input[inOff..input.length] = len;
+
+        return len;
+    }
+    
+    uint padLength(void[] input_) {
+        ubyte[] input = cast(ubyte[]) input_;
+        
+        ubyte len = input[input.length-1];
+         
+        if (len > input.length || len == 0)
+            throw new InvalidPaddingError(name()~": Incorrect padding.");
+        
+        uint limit = input.length;
+        for (int i = 0; i < len; i++)
+            if (input[--limit] != len)
+                throw new InvalidPaddingError(
+                        name()~": Pad value does not match pad length.");
+        return len;
+    }
+}