Add an implementation of McEliece encryption based on HyMES

(https://www.rocq.inria.fr/secret/CBCrypto/index.php?pg=hymes).
The original version is LGPL but cryptsource GmbH has secured
permission to release it under a BSD license. Also includes the
Overbeck CCA2 message encoding scheme.

1 files changed, 57 insertions, 0 deletions

diff --git a/src/lib/pubkey/mce/code_based_util.h b/src/lib/pubkey/mce/code_based_util.h
new file mode 100644
index 000000000..fd8bcaa49
--- /dev/null
+++ b/src/lib/pubkey/mce/code_based_util.h
@@ -0,0 +1,57 @@
+/**
+ * (C) Copyright Projet SECRET, INRIA, Rocquencourt
+ * (C) Bhaskar Biswas and  Nicolas Sendrier
+ *
+ * (C) 2014 cryptosource GmbH
+ * (C) 2014 Falko Strenzke [email protected]
+ *
+ * Distributed under the terms of the Botan license
+ *
+ */
+
+#ifndef BOTAN_CODE_BASED_UTIL_H__
+#define BOTAN_CODE_BASED_UTIL_H__
+
+#include <botan/gf2m_small_m.h>
+
+namespace Botan {
+
+/**
+* Expand an input to a bit mask depending on it being being zero or non-zero
+* @ param tst the input
+* @return the mask 0xFFFF if tst is non-zero and 0 otherwise
+*/
+template<typename T>
+u16bit expand_mask_16bit(T tst)
+   {
+   const u16bit result = (tst != 0);
+   return ~(result - 1);
+   }
+
+inline gf2m_small_m::gf2m gray_to_lex(gf2m_small_m::gf2m gray)
+   {
+   gf2m_small_m::gf2m result = gray ^ (gray>>8);
+   result ^= (result >> 4);
+   result ^= (result >> 2);
+   result ^= (result >> 1);
+   return result;
+   }
+
+inline gf2m_small_m::gf2m lex_to_gray(gf2m_small_m::gf2m lex)
+   {
+   return (lex>>1) ^ lex;
+   }
+
+inline u32bit bit_size_to_byte_size(u32bit bit_size)
+   {
+   return (bit_size - 1) / 8 + 1;
+   }
+
+inline u32bit bit_size_to_32bit_size(u32bit bit_size)
+   {
+   return (bit_size - 1) / 32 + 1;
+   }
+
+}
+
+#endif