1 files changed, 79 insertions, 0 deletions
diff --git a/Crypto/src/crypto/paddings/ISO7816d4Padding.cs b/Crypto/src/crypto/paddings/ISO7816d4Padding.cs
new file mode 100644
index 000000000..016b25a81
--- /dev/null
+++ b/Crypto/src/crypto/paddings/ISO7816d4Padding.cs
@@ -0,0 +1,79 @@
+using System;
+
+using Org.BouncyCastle.Crypto;
+using Org.BouncyCastle.Security;
+
+namespace Org.BouncyCastle.Crypto.Paddings
+{
+ /**
+ * A padder that adds the padding according to the scheme referenced in
+ * ISO 7814-4 - scheme 2 from ISO 9797-1. The first byte is 0x80, rest is 0x00
+ */
+ public class ISO7816d4Padding
+ : IBlockCipherPadding
+ {
+ /**
+ * Initialise the padder.
+ *
+ * @param random - a SecureRandom if available.
+ */
+ public void Init(
+ SecureRandom random)
+ {
+ // nothing to do.
+ }
+
+ /**
+ * Return the name of the algorithm the padder implements.
+ *
+ * @return the name of the algorithm the padder implements.
+ */
+ public string PaddingName
+ {
+ get { return "ISO7816-4"; }
+ }
+
+ /**
+ * add the pad bytes to the passed in block, returning the
+ * number of bytes added.
+ */
+ public int AddPadding(
+ byte[] input,
+ int inOff)
+ {
+ int added = (input.Length - inOff);
+
+ input[inOff]= (byte) 0x80;
+ inOff ++;
+
+ while (inOff < input.Length)
+ {
+ input[inOff] = (byte) 0;
+ inOff++;
+ }
+
+ return added;
+ }
+
+ /**
+ * return the number of pad bytes present in the block.
+ */
+ public int PadCount(
+ byte[] input)
+ {
+ int count = input.Length - 1;
+
+ while (count > 0 && input[count] == 0)
+ {
+ count--;
+ }
+
+ if (input[count] != (byte)0x80)
+ {
+ throw new InvalidCipherTextException("pad block corrupted");
+ }
+
+ return input.Length - count;
+ }
+ }
+}
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