Reorganize the EMSA classes, and remove the last references to prng_reference

in the library ccode.

1 files changed, 56 insertions, 21 deletions

diff --git a/src/emsa2.cpp b/src/emsa2.cpp
index f8d69737a..825329e7e 100644
--- a/src/emsa2.cpp
+++ b/src/emsa2.cpp
@@ -9,6 +9,44 @@
 
 namespace Botan {
 
+namespace {
+
+/*************************************************
+* EMSA2 Encode Operation                         *
+*************************************************/
+SecureVector<byte> emsa2_encoding(const MemoryRegion<byte>& msg,
+                                  u32bit output_bits,
+                                  const MemoryRegion<byte>& empty_hash,
+                                  byte hash_id)
+   {
+   const u32bit HASH_SIZE = empty_hash.size();
+
+   u32bit output_length = (output_bits + 1) / 8;
+
+   if(msg.size() != HASH_SIZE)
+      throw Encoding_Error("EMSA2::encoding_of: Bad input length");
+   if(output_length < HASH_SIZE + 4)
+      throw Encoding_Error("EMSA2::encoding_of: Output length is too small");
+
+   bool empty = true;
+   for(u32bit j = 0; j != HASH_SIZE; ++j)
+      if(empty_hash[j] != msg[j])
+         empty = false;
+
+   SecureVector<byte> output(output_length);
+
+   output[0] = (empty ? 0x4B : 0x6B);
+   output[output_length - 3 - HASH_SIZE] = 0xBA;
+   set_mem(output + 1, output_length - 4 - HASH_SIZE, 0xBB);
+   output.copy(output_length - (HASH_SIZE + 2), msg, msg.size());
+   output[output_length-2] = hash_id;
+   output[output_length-1] = 0xCC;
+
+   return output;
+   }
+
+}
+
 /*************************************************
 * EMSA2 Update Operation                         *
 *************************************************/
@@ -32,28 +70,25 @@ SecureVector<byte> EMSA2::encoding_of(const MemoryRegion<byte>& msg,
                                       u32bit output_bits,
                                       RandomNumberGenerator&)
    {
-   u32bit output_length = (output_bits + 1) / 8;
-
-   if(msg.size() != hash->OUTPUT_LENGTH)
-      throw Encoding_Error("EMSA2::encoding_of: Bad input length");
-   if(output_length < hash->OUTPUT_LENGTH + 4)
-      throw Encoding_Error("EMSA2::encoding_of: Output length is too small");
-
-   bool empty = true;
-   for(u32bit j = 0; j != hash->OUTPUT_LENGTH; ++j)
-      if(empty_hash[j] != msg[j])
-         empty = false;
-
-   SecureVector<byte> output(output_length);
-
-   output[0] = (empty ? 0x4B : 0x6B);
-   output[output_length - 3 - hash->OUTPUT_LENGTH] = 0xBA;
-   set_mem(output + 1, output_length - 4 - hash->OUTPUT_LENGTH, 0xBB);
-   output.copy(output_length-2-hash->OUTPUT_LENGTH, msg, msg.size());
-   output[output_length-2] = hash_id;
-   output[output_length-1] = 0xCC;
+   return emsa2_encoding(msg, output_bits, empty_hash, hash_id);
+   }
 
-   return output;
+/*************************************************
+* EMSA2 Verify Operation                         *
+*************************************************/
+bool EMSA2::verify(const MemoryRegion<byte>& coded,
+                   const MemoryRegion<byte>& raw,
+                   u32bit key_bits) throw()
+   {
+   try
+      {
+      return (coded == emsa2_encoding(raw, key_bits,
+                                      empty_hash, hash_id));
+      }
+   catch(...)
+      {
+      return false;
+      }
    }
 
 /*************************************************