Modularize KDFs, PBKDFs, and PRFs

1 files changed, 81 insertions, 0 deletions

diff --git a/modules/kdf/pbkdf2/pbkdf2.cpp b/modules/kdf/pbkdf2/pbkdf2.cpp
new file mode 100644
index 000000000..09d51d2a6
--- /dev/null
+++ b/modules/kdf/pbkdf2/pbkdf2.cpp
@@ -0,0 +1,81 @@
+/*************************************************
+* PBKDF2 Source File                             *
+* (C) 1999-2007 Jack Lloyd                       *
+*************************************************/
+
+#include <botan/pbkdf2.h>
+#include <botan/loadstor.h>
+#include <botan/hmac.h>
+#include <botan/lookup.h>
+#include <botan/xor_buf.h>
+
+namespace Botan {
+
+/*************************************************
+* Return a PKCS#5 PBKDF2 derived key             *
+*************************************************/
+OctetString PKCS5_PBKDF2::derive(u32bit key_len,
+                                 const std::string& passphrase,
+                                 const byte salt[], u32bit salt_size,
+                                 u32bit iterations) const
+   {
+   if(iterations == 0)
+      throw Invalid_Argument("PKCS#5 PBKDF2: Invalid iteration count");
+
+   if(passphrase.length() == 0)
+      throw Invalid_Argument("PKCS#5 PBKDF2: Empty passphrase is invalid");
+
+   HMAC hmac(hash_name);
+
+   hmac.set_key(reinterpret_cast<const byte*>(passphrase.data()),
+                passphrase.length());
+
+   SecureVector<byte> key(key_len);
+
+   byte* T = key.begin();
+
+   u32bit counter = 1;
+   while(key_len)
+      {
+      u32bit T_size = std::min(hmac.OUTPUT_LENGTH, key_len);
+      SecureVector<byte> U(hmac.OUTPUT_LENGTH);
+
+      hmac.update(salt, salt_size);
+      for(u32bit j = 0; j != 4; ++j)
+         hmac.update(get_byte(j, counter));
+      hmac.final(U);
+      xor_buf(T, U, T_size);
+
+      for(u32bit j = 1; j != iterations; ++j)
+         {
+         hmac.update(U);
+         hmac.final(U);
+         xor_buf(T, U, T_size);
+         }
+
+      key_len -= T_size;
+      T += T_size;
+      ++counter;
+      }
+
+   return key;
+   }
+
+/*************************************************
+* Return the name of this type                   *
+*************************************************/
+std::string PKCS5_PBKDF2::name() const
+   {
+   return "PBKDF2(" + hash_name + ")";
+   }
+
+/*************************************************
+* PKCS5_PBKDF2 Constructor                       *
+*************************************************/
+PKCS5_PBKDF2::PKCS5_PBKDF2(const std::string& h_name) : hash_name(h_name)
+   {
+   if(!have_hash(hash_name))
+      throw Algorithm_Not_Found(hash_name);
+   }
+
+}