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, 22 insertions, 0 deletions

diff --git a/src/lib/utils/bit_ops.h b/src/lib/utils/bit_ops.h
index 0072fde71..75a7584ad 100644
--- a/src/lib/utils/bit_ops.h
+++ b/src/lib/utils/bit_ops.h
@@ -1,6 +1,10 @@
 /*
 * Bit/Word Operations
 * (C) 1999-2008 Jack Lloyd
+* (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
 */
@@ -98,6 +102,24 @@ inline size_t ctz(T n)
    return 8*sizeof(T);
    }
 
+template<typename T>
+size_t ceil_log2(T x)
+   {
+   if(x >> (sizeof(T)*8-1))
+      return sizeof(T)*8;
+
+   size_t result = 0;
+   T compare = 1;
+
+   while(compare < x)
+      {
+      compare <<= 1;
+      result++;
+      }
+
+   return result;
+   }
+
 }
 
 #endif