1 files changed, 102 insertions, 0 deletions
diff --git a/crypto/src/openpgp/SXprUtilities.cs b/crypto/src/openpgp/SXprUtilities.cs
new file mode 100644
index 000000000..68ff373a8
--- /dev/null
+++ b/crypto/src/openpgp/SXprUtilities.cs
@@ -0,0 +1,102 @@
+using System;
+using System.IO;
+
+using Org.BouncyCastle.Utilities.IO;
+
+namespace Org.BouncyCastle.Bcpg.OpenPgp
+{
+ /**
+ * Utility functions for looking a S-expression keys. This class will move when it finds a better home!
+ * <p>
+ * Format documented here:
+ * http://git.gnupg.org/cgi-bin/gitweb.cgi?p=gnupg.git;a=blob;f=agent/keyformat.txt;h=42c4b1f06faf1bbe71ffadc2fee0fad6bec91a97;hb=refs/heads/master
+ * </p>
+ */
+ public sealed class SXprUtilities
+ {
+ private SXprUtilities()
+ {
+ }
+
+ private static int ReadLength(Stream input, int ch)
+ {
+ int len = ch - '0';
+
+ while ((ch = input.ReadByte()) >= 0 && ch != ':')
+ {
+ len = len * 10 + ch - '0';
+ }
+
+ return len;
+ }
+
+ internal static string ReadString(Stream input, int ch)
+ {
+ int len = ReadLength(input, ch);
+
+ char[] chars = new char[len];
+
+ for (int i = 0; i != chars.Length; i++)
+ {
+ chars[i] = (char)input.ReadByte();
+ }
+
+ return new string(chars);
+ }
+
+ internal static byte[] ReadBytes(Stream input, int ch)
+ {
+ int len = ReadLength(input, ch);
+
+ byte[] data = new byte[len];
+
+ Streams.ReadFully(input, data);
+
+ return data;
+ }
+
+ internal static S2k ParseS2k(Stream input)
+ {
+ SkipOpenParenthesis(input);
+
+ string alg = ReadString(input, input.ReadByte());
+ byte[] iv = ReadBytes(input, input.ReadByte());
+ long iterationCount = Int64.Parse(ReadString(input, input.ReadByte()));
+
+ SkipCloseParenthesis(input);
+
+ // we have to return the actual iteration count provided.
+ return new MyS2k(HashAlgorithmTag.Sha1, iv, iterationCount);
+ }
+
+ internal static void SkipOpenParenthesis(Stream input)
+ {
+ int ch = input.ReadByte();
+ if (ch != '(')
+ throw new IOException("unknown character encountered");
+ }
+
+ internal static void SkipCloseParenthesis(Stream input)
+ {
+ int ch = input.ReadByte();
+ if (ch != ')')
+ throw new IOException("unknown character encountered");
+ }
+
+ private class MyS2k : S2k
+ {
+ private readonly long mIterationCount64;
+
+ internal MyS2k(HashAlgorithmTag algorithm, byte[] iv, long iterationCount64)
+ : base(algorithm, iv, (int)iterationCount64)
+ {
+ this.mIterationCount64 = iterationCount64;
+ }
+
+ public override long IterationCount
+ {
+ get { return mIterationCount64; }
+ }
+ }
+ }
+}
|
