Add SHAKE-128 and SHAKE-256 as hash functions

1 files changed, 101 insertions, 0 deletions

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();
+   }
+
+}