1 files changed, 152 insertions, 0 deletions
diff --git a/lib/pk_pad/emsa3/emsa3.cpp b/lib/pk_pad/emsa3/emsa3.cpp
new file mode 100644
index 000000000..0d603c508
--- /dev/null
+++ b/lib/pk_pad/emsa3/emsa3.cpp
@@ -0,0 +1,152 @@
+/*
+* EMSA3 and EMSA3_Raw
+* (C) 1999-2008 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/emsa3.h>
+#include <botan/hash_id.h>
+
+namespace Botan {
+
+namespace {
+
+/*
+* EMSA3 Encode Operation
+*/
+secure_vector<byte> emsa3_encoding(const secure_vector<byte>& msg,
+                                  size_t output_bits,
+                                  const byte hash_id[],
+                                  size_t hash_id_length)
+   {
+   size_t output_length = output_bits / 8;
+   if(output_length < hash_id_length + msg.size() + 10)
+      throw Encoding_Error("emsa3_encoding: Output length is too small");
+
+   secure_vector<byte> T(output_length);
+   const size_t P_LENGTH = output_length - msg.size() - hash_id_length - 2;
+
+   T[0] = 0x01;
+   set_mem(&T[1], P_LENGTH, 0xFF);
+   T[P_LENGTH+1] = 0x00;
+   buffer_insert(T, P_LENGTH+2, hash_id, hash_id_length);
+   buffer_insert(T, output_length-msg.size(), &msg[0], msg.size());
+   return T;
+   }
+
+}
+
+/*
+* EMSA3 Update Operation
+*/
+void EMSA3::update(const byte input[], size_t length)
+   {
+   hash->update(input, length);
+   }
+
+/*
+* Return the raw (unencoded) data
+*/
+secure_vector<byte> EMSA3::raw_data()
+   {
+   return hash->final();
+   }
+
+/*
+* EMSA3 Encode Operation
+*/
+secure_vector<byte> EMSA3::encoding_of(const secure_vector<byte>& msg,
+                                      size_t output_bits,
+                                      RandomNumberGenerator&)
+   {
+   if(msg.size() != hash->output_length())
+      throw Encoding_Error("EMSA3::encoding_of: Bad input length");
+
+   return emsa3_encoding(msg, output_bits,
+                         &hash_id[0], hash_id.size());
+   }
+
+/*
+* Default signature decoding
+*/
+bool EMSA3::verify(const secure_vector<byte>& coded,
+                   const secure_vector<byte>& raw,
+                   size_t key_bits)
+   {
+   if(raw.size() != hash->output_length())
+      return false;
+
+   try
+      {
+      return (coded == emsa3_encoding(raw, key_bits,
+                                      &hash_id[0], hash_id.size()));
+      }
+   catch(...)
+      {
+      return false;
+      }
+   }
+
+/*
+* EMSA3 Constructor
+*/
+EMSA3::EMSA3(HashFunction* hash_in) : hash(hash_in)
+   {
+   hash_id = pkcs_hash_id(hash->name());
+   }
+
+/*
+* EMSA3 Destructor
+*/
+EMSA3::~EMSA3()
+   {
+   delete hash;
+   }
+
+/*
+* EMSA3_Raw Update Operation
+*/
+void EMSA3_Raw::update(const byte input[], size_t length)
+   {
+   message += std::make_pair(input, length);
+   }
+
+/*
+* Return the raw (unencoded) data
+*/
+secure_vector<byte> EMSA3_Raw::raw_data()
+   {
+   secure_vector<byte> ret;
+   std::swap(ret, message);
+   return ret;
+   }
+
+/*
+* EMSA3_Raw Encode Operation
+*/
+secure_vector<byte> EMSA3_Raw::encoding_of(const secure_vector<byte>& msg,
+                                          size_t output_bits,
+                                          RandomNumberGenerator&)
+   {
+   return emsa3_encoding(msg, output_bits, nullptr, 0);
+   }
+
+/*
+* Default signature decoding
+*/
+bool EMSA3_Raw::verify(const secure_vector<byte>& coded,
+                       const secure_vector<byte>& raw,
+                       size_t key_bits)
+   {
+   try
+      {
+      return (coded == emsa3_encoding(raw, key_bits, nullptr, 0));
+      }
+   catch(...)
+      {
+      return false;
+      }
+   }
+
+}