Add SHAKE-128 and SHAKE-256 as hash functions

3 files changed, 187 insertions, 0 deletions

diff --git a/src/lib/hash/shake/info.txt b/src/lib/hash/shake/info.txt
new file mode 100644
index 000000000..f579383eb
--- /dev/null
+++ b/src/lib/hash/shake/info.txt
@@ -0,0 +1,5 @@
+define SHAKE 20161009
+
+<requires>
+sha3
+</requires>
diff --git a/src/lib/hash/shake/shake.cpp b/src/lib/hash/shake/shake.cpp
new file mode 100644
index 000000000..1ff6f1fd3
--- /dev/null
+++ b/src/lib/hash/shake/shake.cpp
@@ -0,0 +1,101 @@
+/*
+* SHAKE-128/256 as a hash
+* (C) 2016 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/shake.h>
+#include <botan/sha3.h>
+#include <botan/parsing.h>
+#include <botan/exceptn.h>
+
+namespace Botan {
+
+SHAKE_128::SHAKE_128(size_t output_bits) :
+   m_output_bits(output_bits), m_S(25), m_S_pos(0)
+   {
+   if(output_bits % 8 != 0)
+      throw Invalid_Argument("SHAKE_128: Invalid output length " +
+                             std::to_string(output_bits));
+   }
+
+std::string SHAKE_128::name() const
+   {
+   return "SHAKE-128(" + std::to_string(m_output_bits) + ")";
+   }
+
+HashFunction* SHAKE_128::clone() const
+   {
+   return new SHAKE_128(m_output_bits);
+   }
+
+void SHAKE_128::clear()
+   {
+   zeroise(m_S);
+   m_S_pos = 0;
+   }
+
+void SHAKE_128::add_data(const byte input[], size_t length)
+   {
+   m_S_pos = SHA_3::absorb(SHAKE_128_BITRATE, m_S, m_S_pos, input, length);
+   }
+
+void SHAKE_128::final_result(byte output[])
+   {
+   std::vector<byte> padding(SHAKE_128_BITRATE / 8 - m_S_pos);
+
+   padding[0] = 0x1F;
+   padding[padding.size()-1] |= 0x80;
+
+   add_data(padding.data(), padding.size());
+
+   SHA_3::expand(SHAKE_128_BITRATE, m_S, output, output_length());
+
+   clear();
+   }
+
+SHAKE_256::SHAKE_256(size_t output_bits) :
+   m_output_bits(output_bits), m_S(25), m_S_pos(0)
+   {
+   if(output_bits % 8 != 0)
+      throw Invalid_Argument("SHAKE_256: Invalid output length " +
+                             std::to_string(output_bits));
+   }
+
+std::string SHAKE_256::name() const
+   {
+   return "SHAKE-256(" + std::to_string(m_output_bits) + ")";
+   }
+
+HashFunction* SHAKE_256::clone() const
+   {
+   return new SHAKE_256(m_output_bits);
+   }
+
+void SHAKE_256::clear()
+   {
+   zeroise(m_S);
+   m_S_pos = 0;
+   }
+
+void SHAKE_256::add_data(const byte input[], size_t length)
+   {
+   m_S_pos = SHA_3::absorb(SHAKE_256_BITRATE, m_S, m_S_pos, input, length);
+   }
+
+void SHAKE_256::final_result(byte output[])
+   {
+   std::vector<byte> padding(SHAKE_256_BITRATE / 8 - m_S_pos);
+
+   padding[0] = 0x1F;
+   padding[padding.size()-1] |= 0x80;
+
+   add_data(padding.data(), padding.size());
+
+   SHA_3::expand(SHAKE_256_BITRATE, m_S, output, output_length());
+
+   clear();
+   }
+
+}
diff --git a/src/lib/hash/shake/shake.h b/src/lib/hash/shake/shake.h
new file mode 100644
index 000000000..96c171323
--- /dev/null
+++ b/src/lib/hash/shake/shake.h
@@ -0,0 +1,81 @@
+/*
+* SHAKE hash functions
+* (C) 2010,2016 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_SHAKE_HASH_H__
+#define BOTAN_SHAKE_HASH_H__
+
+#include <botan/hash.h>
+#include <botan/secmem.h>
+#include <string>
+
+namespace Botan {
+
+/**
+* SHAKE-128
+*/
+class BOTAN_DLL SHAKE_128 : public HashFunction
+   {
+   public:
+
+      /**
+      * @param output_bits the desired output size in bits
+      * must be a multiple of 8
+      */
+      SHAKE_128(size_t output_bits);
+
+      size_t hash_block_size() const override { return SHAKE_128_BITRATE / 8; }
+      size_t output_length() const override { return m_output_bits / 8; }
+
+      HashFunction* clone() const override;
+      std::string name() const override;
+      void clear() override;
+
+   private:
+      void add_data(const byte input[], size_t length) override;
+      void final_result(byte out[]) override;
+
+      static const size_t SHAKE_128_BITRATE = 1600 - 256;
+
+      size_t m_output_bits;
+      secure_vector<u64bit> m_S;
+      size_t m_S_pos;
+   };
+
+/**
+* SHAKE-256
+*/
+class BOTAN_DLL SHAKE_256 : public HashFunction
+   {
+   public:
+
+      /**
+      * @param output_bits the desired output size in bits
+      * must be a multiple of 8
+      */
+      SHAKE_256(size_t output_bits);
+
+      size_t hash_block_size() const override { return SHAKE_256_BITRATE / 8; }
+      size_t output_length() const override { return m_output_bits / 8; }
+
+      HashFunction* clone() const override;
+      std::string name() const override;
+      void clear() override;
+
+   private:
+      void add_data(const byte input[], size_t length) override;
+      void final_result(byte out[]) override;
+
+      static const size_t SHAKE_256_BITRATE = 1600 - 512;
+
+      size_t m_output_bits;
+      secure_vector<u64bit> m_S;
+      size_t m_S_pos;
+   };
+
+}
+
+#endif