Add format preserving encryption, design is FE1/FD1 from the paper

Format-Preserving Encryption (http://eprint.iacr.org/2009/251). This
doesn't implement the rank functions which are necessary for the actual
format-preserving part, though that would be nice to add to the example.

1 files changed, 22 insertions, 0 deletions

diff --git a/doc/examples/fpe.cpp b/doc/examples/fpe.cpp
new file mode 100644
index 000000000..9384a0d2d
--- /dev/null
+++ b/doc/examples/fpe.cpp
@@ -0,0 +1,22 @@
+#include <botan/fpe.h>
+#include <botan/init.h>
+
+using namespace Botan;
+
+#include <iostream>
+
+int main()
+   {
+   LibraryInitializer init;
+
+   BigInt n = 100000000;
+   BigInt x = 49604394;
+
+   SymmetricKey key("AAAAAAAAAAAAAAAA");
+   MemoryVector<byte> tweak(4);
+
+   BigInt c = fpe_encrypt(n, x, key, tweak);
+   BigInt p = fpe_decrypt(n, c, key, tweak);
+
+   std::cout << c << ' ' << p << ' ' << x << '\n';
+   }