1 files changed, 108 insertions, 0 deletions
diff --git a/src/lib/hash/mdx_hash/mdx_hash.cpp b/src/lib/hash/mdx_hash/mdx_hash.cpp
new file mode 100644
index 000000000..81042c1fa
--- /dev/null
+++ b/src/lib/hash/mdx_hash/mdx_hash.cpp
@@ -0,0 +1,108 @@
+/*
+* Merkle-Damgard Hash Function
+* (C) 1999-2008 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/mdx_hash.h>
+#include <botan/exceptn.h>
+#include <botan/loadstor.h>
+
+namespace Botan {
+
+/*
+* MDx_HashFunction Constructor
+*/
+MDx_HashFunction::MDx_HashFunction(size_t block_len,
+                                   bool byte_end,
+                                   bool bit_end,
+                                   size_t cnt_size) :
+   buffer(block_len),
+   BIG_BYTE_ENDIAN(byte_end),
+   BIG_BIT_ENDIAN(bit_end),
+   COUNT_SIZE(cnt_size)
+   {
+   count = position = 0;
+   }
+
+/*
+* Clear memory of sensitive data
+*/
+void MDx_HashFunction::clear()
+   {
+   zeroise(buffer);
+   count = position = 0;
+   }
+
+/*
+* Update the hash
+*/
+void MDx_HashFunction::add_data(const byte input[], size_t length)
+   {
+   count += length;
+
+   if(position)
+      {
+      buffer_insert(buffer, position, input, length);
+
+      if(position + length >= buffer.size())
+         {
+         compress_n(&buffer[0], 1);
+         input += (buffer.size() - position);
+         length -= (buffer.size() - position);
+         position = 0;
+         }
+      }
+
+   const size_t full_blocks = length / buffer.size();
+   const size_t remaining   = length % buffer.size();
+
+   if(full_blocks)
+      compress_n(input, full_blocks);
+
+   buffer_insert(buffer, position, input + full_blocks * buffer.size(), remaining);
+   position += remaining;
+   }
+
+/*
+* Finalize a hash
+*/
+void MDx_HashFunction::final_result(byte output[])
+   {
+   buffer[position] = (BIG_BIT_ENDIAN ? 0x80 : 0x01);
+   for(size_t i = position+1; i != buffer.size(); ++i)
+      buffer[i] = 0;
+
+   if(position >= buffer.size() - COUNT_SIZE)
+      {
+      compress_n(&buffer[0], 1);
+      zeroise(buffer);
+      }
+
+   write_count(&buffer[buffer.size() - COUNT_SIZE]);
+
+   compress_n(&buffer[0], 1);
+   copy_out(output);
+   clear();
+   }
+
+/*
+* Write the count bits to the buffer
+*/
+void MDx_HashFunction::write_count(byte out[])
+   {
+   if(COUNT_SIZE < 8)
+      throw Invalid_State("MDx_HashFunction::write_count: COUNT_SIZE < 8");
+   if(COUNT_SIZE >= output_length() || COUNT_SIZE >= hash_block_size())
+      throw Invalid_Argument("MDx_HashFunction: COUNT_SIZE is too big");
+
+   const u64bit bit_count = count * 8;
+
+   if(BIG_BYTE_ENDIAN)
+      store_be(bit_count, out + COUNT_SIZE - 8);
+   else
+      store_le(bit_count, out + COUNT_SIZE - 8);
+   }
+
+}