Add comment explaining why EAX tests for XTEA, Skipjack, and Noekeon

are not run (the implementations in LTC are incompatible with the ones
in Botan, mostly due to endian differences in underspecified algorithms).
The DES, 3DES, AES, Twofish, Blowfish, RC2, RC5, RC6, and SAFER-SK tests
of EAX mode from LTC all pass.

1 files changed, 19 insertions, 6 deletions

diff --git a/doc/examples/eax_test.cpp b/doc/examples/eax_test.cpp
index 2e0790257..b69aec5e9 100644
--- a/doc/examples/eax_test.cpp
+++ b/doc/examples/eax_test.cpp
@@ -120,9 +120,6 @@ std::pair<std::string, int> translate_algo(const std::string& in)
    if(in == "blowfish (8 byte key)")
       return std::make_pair("Blowfish", 8);
 
-   if(in == "xtea (16 byte key)xxx")
-      return std::make_pair("XTEA", 16);
-
    if(in == "rc2 (8 byte key)")
       return std::make_pair("RC2", 8);
 
@@ -144,12 +141,28 @@ std::pair<std::string, int> translate_algo(const std::string& in)
    if(in == "3des (24 byte key)")
       return std::make_pair("TripleDES", 24);
 
-   if(in == "noekeon (16 byte key)xxx")
-      return std::make_pair("Noekeon", 16);
+   // These 3 are disabled due to differences in base algorithm.
+
+#if 0
+   // XTEA: LTC uses little endian, Botan (and Crypto++) use big-endian
+   // I swapped to LE in XTEA and the vectors did match
+   if(in == "xtea (16 byte key)")
+      return std::make_pair("XTEA", 16);
 
-   if(in == "skipjack (10 byte key)xxx")
+   // Skipjack: LTC uses big-endian, Botan (and Crypto++) use
+   // little-endian I am not sure if that was the full difference
+   // though, was unable to replicate LTC's EAX vectors with Skipjack
+   if(in == "skipjack (10 byte key)")
       return std::make_pair("Skipjack", 10);
 
+   // Noekeon: unknown cause, though LTC's lone test vector does not
+   // match Botan
+
+   if(in == "noekeon (16 byte key)")
+      return std::make_pair("Noekeon", 16);
+
+#endif
+
    return std::make_pair("", 0);
    }