1 files changed, 57 insertions, 0 deletions
diff --git a/src/pbkdf/pgps2k/pgp_s2k.cpp b/src/pbkdf/pgps2k/pgp_s2k.cpp
new file mode 100644
index 000000000..db18adaf1
--- /dev/null
+++ b/src/pbkdf/pgps2k/pgp_s2k.cpp
@@ -0,0 +1,57 @@
+/*
+* OpenPGP S2K
+* (C) 1999-2007 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/pgp_s2k.h>
+
+namespace Botan {
+
+/*
+* Derive a key using the OpenPGP S2K algorithm
+*/
+OctetString OpenPGP_S2K::derive_key(u32bit key_len,
+                                    const std::string& passphrase,
+                                    const byte salt_buf[], u32bit salt_size,
+                                    u32bit iterations) const
+   {
+   SecureVector<byte> key(key_len), hash_buf;
+
+   u32bit pass = 0, generated = 0,
+          total_size = passphrase.size() + salt_size;
+   u32bit to_hash = std::max(iterations, total_size);
+
+   hash->clear();
+   while(key_len > generated)
+      {
+      for(u32bit j = 0; j != pass; ++j)
+         hash->update(0);
+
+      u32bit left = to_hash;
+      while(left >= total_size)
+         {
+         hash->update(salt_buf, salt_size);
+         hash->update(passphrase);
+         left -= total_size;
+         }
+      if(left <= salt_size)
+         hash->update(salt_buf, left);
+      else
+         {
+         hash->update(salt_buf, salt_size);
+         left -= salt_size;
+         hash->update(reinterpret_cast<const byte*>(passphrase.data()), left);
+         }
+
+      hash_buf = hash->final();
+      key.copy(generated, hash_buf, hash->OUTPUT_LENGTH);
+      generated += hash->OUTPUT_LENGTH;
+      ++pass;
+      }
+
+   return key;
+   }
+
+}