1 files changed, 85 insertions, 0 deletions
diff --git a/botan/src/kdf/tls_prf/prf_tls.cpp b/botan/src/kdf/tls_prf/prf_tls.cpp
new file mode 100644
index 0000000..7c638b9
--- /dev/null
+++ b/botan/src/kdf/tls_prf/prf_tls.cpp
@@ -0,0 +1,85 @@
+/*
+* TLS PRF
+* (C) 2004-2006 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/prf_tls.h>
+#include <botan/xor_buf.h>
+#include <botan/hmac.h>
+#include <botan/md5.h>
+#include <botan/sha160.h>
+
+namespace Botan {
+
+namespace {
+
+/*
+* TLS PRF P_hash function
+*/
+SecureVector<byte> P_hash(MessageAuthenticationCode* mac,
+                          u32bit len,
+                          const byte secret[], u32bit secret_len,
+                          const byte seed[], u32bit seed_len)
+   {
+   SecureVector<byte> out;
+
+   mac->set_key(secret, secret_len);
+
+   SecureVector<byte> A(seed, seed_len);
+   while(len)
+      {
+      const u32bit this_block_len = std::min(mac->OUTPUT_LENGTH, len);
+
+      A = mac->process(A);
+
+      mac->update(A);
+      mac->update(seed, seed_len);
+      SecureVector<byte> block = mac->final();
+
+      out.append(block, this_block_len);
+      len -= this_block_len;
+      }
+   return out;
+   }
+
+}
+
+/*
+* TLS PRF Constructor and Destructor
+*/
+TLS_PRF::TLS_PRF()
+   {
+   hmac_md5 = new HMAC(new MD5);
+   hmac_sha1 = new HMAC(new SHA_160);
+   }
+
+TLS_PRF::~TLS_PRF()
+   {
+   delete hmac_md5;
+   delete hmac_sha1;
+   }
+
+/*
+* TLS PRF
+*/
+SecureVector<byte> TLS_PRF::derive(u32bit key_len,
+                                   const byte secret[], u32bit secret_len,
+                                   const byte seed[], u32bit seed_len) const
+   {
+   u32bit S1_len = (secret_len + 1) / 2,
+          S2_len = (secret_len + 1) / 2;
+   const byte* S1 = secret;
+   const byte* S2 = secret + (secret_len - S2_len);
+
+   SecureVector<byte> key1, key2;
+   key1 = P_hash(hmac_md5,  key_len, S1, S1_len, seed, seed_len);
+   key2 = P_hash(hmac_sha1, key_len, S2, S2_len, seed, seed_len);
+
+   xor_buf(key1.begin(), key2.begin(), key2.size());
+
+   return key1;
+   }
+
+}