bitbeans · May 24, 2024 04:18 · Aug 16, 2015 · Aug 16, 2015
diff --git a/Pkcs7.cs b/Pkcs7.cs
@@ -9,6 +9,11 @@
 /// <exception cref="ArgumentNullException"></exception>
 public static byte[] RemovePkcs7Padding(byte[] paddedByteArray)
 {
+    if (paddedByteArray == null)
+    {
+        throw new ArgumentNullException("paddedByteArray", "paddedByteArray can not be null");
+    }
+
     var last = paddedByteArray[paddedByteArray.Length - 1];
     if (paddedByteArray.Length <= last)
     {
@@ -31,6 +36,15 @@ public static byte[] RemovePkcs7Padding(byte[] paddedByteArray)
 /// <exception cref="ArgumentOutOfRangeException"></exception>
 public static byte[] AddPkcs7Padding(byte[] data, int paddingLength)
 {
+    if (data.Length > 256)
+    {
+        throw new ArgumentOutOfRangeException("data", "data must be <= 256 in length");
+    }
+    if (paddingLength > 256)
+    {
+        throw new ArgumentOutOfRangeException("paddingLength", "paddingLength must be <= 256");
+    }
+
     if (paddingLength <= data.Length)
     {
         // there is nothing to pad

diff --git a/Pkcs7.cs b/Pkcs7.cs
@@ -0,0 +1,66 @@
+/// <summary>
+///     Removes the Pkcs7 padding of an array.
+/// </summary>
+/// <param name="paddedByteArray">The padded array.</param>
+/// <returns>The unpadded array.</returns>
+/// <exception cref="OverflowException"></exception>
+/// <exception cref="ArgumentOutOfRangeException"></exception>
+/// <exception cref="ArgumentException"></exception>
+/// <exception cref="ArgumentNullException"></exception>
+public static byte[] RemovePkcs7Padding(byte[] paddedByteArray)
+{
+    var last = paddedByteArray[paddedByteArray.Length - 1];
+    if (paddedByteArray.Length <= last)
+    {
+        // there is nothing to unpad
+        return paddedByteArray;
+    }
+
+    return SubArray(paddedByteArray, 0, (paddedByteArray.Length - last));
+}
+
+/// <summary>
+///     Fill up an array with Pkcs7 padding.
+/// </summary>
+/// <param name="data">The source array.</param>
+/// <param name="paddingLength">The length of the padding.</param>
+/// <returns>The padded array.</returns>
+/// <exception cref="OverflowException"></exception>
+/// <exception cref="ArgumentNullException"></exception>
+/// <exception cref="ArgumentException"></exception>
+/// <exception cref="ArgumentOutOfRangeException"></exception>
+public static byte[] AddPkcs7Padding(byte[] data, int paddingLength)
+{
+    if (paddingLength <= data.Length)
+    {
+        // there is nothing to pad
+        return data;
+    }
+
+    var output = new byte[paddingLength];
+    Buffer.BlockCopy(data, 0, output, 0, data.Length);
+    for (var i = data.Length; i < output.Length; i++)
+    {
+        output[i] = (byte) (paddingLength - data.Length);
+    }
+    return output;
+}
+
+/// <summary>
+///     Extract a part of a byte array from another byte array.
+/// </summary>
+/// <typeparam name="T"></typeparam>
+/// <param name="arr">A byte array.</param>
+/// <param name="start">Position to start extraction.</param>
+/// <param name="length">The length of the extraction started at start.</param>
+/// <returns>A part with the given length of the byte array.</returns>
+/// <exception cref="ArgumentNullException"></exception>
+/// <exception cref="ArgumentException"></exception>
+/// <exception cref="ArgumentOutOfRangeException"></exception>
+public static T[] SubArray<T>(T[] arr, int start, int length)
+{
+    var result = new T[length];
+    Buffer.BlockCopy(arr, start, result, 0, length);
+
+    return result;
+}