1 files changed, 45 insertions, 0 deletions
diff --git a/crypto/src/openpgp/PgpPad.cs b/crypto/src/openpgp/PgpPad.cs
new file mode 100644
index 000000000..48f7f2f44
--- /dev/null
+++ b/crypto/src/openpgp/PgpPad.cs
@@ -0,0 +1,45 @@
+using System;
+
+namespace Org.BouncyCastle.Bcpg.OpenPgp
+{
+ /// <remarks>Padding functions.</remarks>
+ public sealed class PgpPad
+ {
+ private PgpPad()
+ {
+ }
+
+ public static byte[] PadSessionData(byte[] sessionInfo)
+ {
+ byte[] result = new byte[40];
+
+ Array.Copy(sessionInfo, 0, result, 0, sessionInfo.Length);
+
+ byte padValue = (byte)(result.Length - sessionInfo.Length);
+
+ for (int i = sessionInfo.Length; i != result.Length; i++)
+ {
+ result[i] = padValue;
+ }
+
+ return result;
+ }
+
+ public static byte[] UnpadSessionData(byte[] encoded)
+ {
+ byte padValue = encoded[encoded.Length - 1];
+
+ for (int i = encoded.Length - padValue; i != encoded.Length; i++)
+ {
+ if (encoded[i] != padValue)
+ throw new PgpException("bad padding found in session data");
+ }
+
+ byte[] taggedKey = new byte[encoded.Length - padValue];
+
+ Array.Copy(encoded, 0, taggedKey, 0, taggedKey.Length);
+
+ return taggedKey;
+ }
+ }
+}
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