diff --git a/Crypto/src/util/encoders/HexEncoder.cs b/Crypto/src/util/encoders/HexEncoder.cs
new file mode 100644
index 000000000..c47d6219b
--- /dev/null
+++ b/Crypto/src/util/encoders/HexEncoder.cs
@@ -0,0 +1,164 @@
+using System;
+using System.IO;
+
+namespace Org.BouncyCastle.Utilities.Encoders
+{
+ public class HexEncoder
+ : IEncoder
+ {
+ private static readonly byte[] encodingTable =
+ {
+ (byte)'0', (byte)'1', (byte)'2', (byte)'3', (byte)'4', (byte)'5', (byte)'6', (byte)'7',
+ (byte)'8', (byte)'9', (byte)'a', (byte)'b', (byte)'c', (byte)'d', (byte)'e', (byte)'f'
+ };
+
+ /*
+ * set up the decoding table.
+ */
+ internal static readonly byte[] decodingTable = new byte[128];
+
+ static HexEncoder()
+ {
+ for (int i = 0; i < encodingTable.Length; i++)
+ {
+ decodingTable[encodingTable[i]] = (byte)i;
+ }
+
+ decodingTable['A'] = decodingTable['a'];
+ decodingTable['B'] = decodingTable['b'];
+ decodingTable['C'] = decodingTable['c'];
+ decodingTable['D'] = decodingTable['d'];
+ decodingTable['E'] = decodingTable['e'];
+ decodingTable['F'] = decodingTable['f'];
+ }
+
+ /**
+ * encode the input data producing a Hex output stream.
+ *
+ * @return the number of bytes produced.
+ */
+ public int Encode(
+ byte[] data,
+ int off,
+ int length,
+ Stream outStream)
+ {
+ for (int i = off; i < (off + length); i++)
+ {
+ int v = data[i];
+
+ outStream.WriteByte(encodingTable[v >> 4]);
+ outStream.WriteByte(encodingTable[v & 0xf]);
+ }
+
+ return length * 2;
+ }
+
+ private bool ignore(
+ char c)
+ {
+ return (c == '\n' || c =='\r' || c == '\t' || c == ' ');
+ }
+
+ /**
+ * decode the Hex encoded byte data writing it to the given output stream,
+ * whitespace characters will be ignored.
+ *
+ * @return the number of bytes produced.
+ */
+ public int Decode(
+ byte[] data,
+ int off,
+ int length,
+ Stream outStream)
+ {
+ byte b1, b2;
+ int outLen = 0;
+ int end = off + length;
+
+ while (end > off)
+ {
+ if (!ignore((char)data[end - 1]))
+ {
+ break;
+ }
+
+ end--;
+ }
+
+ int i = off;
+ while (i < end)
+ {
+ while (i < end && ignore((char)data[i]))
+ {
+ i++;
+ }
+
+ b1 = decodingTable[data[i++]];
+
+ while (i < end && ignore((char)data[i]))
+ {
+ i++;
+ }
+
+ b2 = decodingTable[data[i++]];
+
+ outStream.WriteByte((byte)((b1 << 4) | b2));
+
+ outLen++;
+ }
+
+ return outLen;
+ }
+
+ /**
+ * decode the Hex encoded string data writing it to the given output stream,
+ * whitespace characters will be ignored.
+ *
+ * @return the number of bytes produced.
+ */
+ public int DecodeString(
+ string data,
+ Stream outStream)
+ {
+ byte b1, b2;
+ int length = 0;
+
+ int end = data.Length;
+
+ while (end > 0)
+ {
+ if (!ignore(data[end - 1]))
+ {
+ break;
+ }
+
+ end--;
+ }
+
+ int i = 0;
+ while (i < end)
+ {
+ while (i < end && ignore(data[i]))
+ {
+ i++;
+ }
+
+ b1 = decodingTable[data[i++]];
+
+ while (i < end && ignore(data[i]))
+ {
+ i++;
+ }
+
+ b2 = decodingTable[data[i++]];
+
+ outStream.WriteByte((byte)((b1 << 4) | b2));
+
+ length++;
+ }
+
+ return length;
+ }
+ }
+}
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