1 files changed, 141 insertions, 0 deletions
diff --git a/misc/cms/cms_algo.cpp b/misc/cms/cms_algo.cpp
new file mode 100644
index 000000000..8143bbe5c
--- /dev/null
+++ b/misc/cms/cms_algo.cpp
@@ -0,0 +1,141 @@
+/*************************************************
+* CMS Algorithm Specific Code Source File        *
+* (C) 1999-2003 The Botan Project                *
+*************************************************/
+
+#include <botan/cms_enc.h>
+#include <botan/der_enc.h>
+#include <botan/lookup.h>
+#include <botan/filters.h>
+#include <botan/rng.h>
+#include <botan/rc2.h>
+
+namespace Botan {
+
+namespace {
+
+/*************************************************
+* Wrap a key as specified in RFC 3217            *
+*************************************************/
+SecureVector<byte> do_rfc3217_wrap(const std::string& cipher,
+                                   const SymmetricKey& kek,
+                                   const SecureVector<byte>& input)
+   {
+   class Flip_Bytes : public Filter
+      {
+      public:
+         void write(const byte data[], u32bit length)
+            {
+            buf.append(data, length);
+            }
+         void end_msg()
+            {
+            for(u32bit j = 0; j != buf.size(); j++)
+               send(buf[buf.size()-j-1]);
+            buf.destroy();
+            }
+         Flip_Bytes(const SecureVector<byte>& prefix) { buf.append(prefix); }
+      private:
+         SecureVector<byte> buf;
+      };
+
+   if(block_size_of(cipher) != 8)
+      throw Encoding_Error("do_rfc3217_wrap: Bad cipher: " + cipher);
+
+   Pipe icv(new Hash_Filter("SHA-160", 8));
+   icv.process_msg(input);
+
+   InitializationVector iv(8);
+   InitializationVector fixed("4ADDA22C79E82105");
+
+   Pipe pipe(get_cipher(cipher + "/CBC/NoPadding", kek, iv, ENCRYPTION),
+             new Flip_Bytes(iv.copy()),
+             get_cipher(cipher + "/CBC/NoPadding", kek, fixed, ENCRYPTION));
+   pipe.start_msg();
+   pipe.write(input);
+   pipe.write(icv.read_all());
+   pipe.end_msg();
+   return pipe.read_all();
+   }
+
+}
+
+/*************************************************
+* Wrap a CEK with a KEK                          *
+*************************************************/
+SecureVector<byte> CMS_Encoder::wrap_key(const std::string& cipher,
+                                         const SymmetricKey& cek,
+                                         const SymmetricKey& kek)
+   {
+   if(cipher == "TripleDES")
+      {
+      SymmetricKey cek_parity = cek;
+      cek_parity.set_odd_parity();
+      return do_rfc3217_wrap(cipher, kek, cek_parity.copy());
+      }
+   else if(cipher == "RC2" || cipher == "CAST-128")
+      {
+      if(kek.length() != 16)
+         throw Encoding_Error("CMS: 128-bit KEKs must be used with " + cipher);
+
+      SecureVector<byte> lcekpad;
+      lcekpad.append((byte)cek.length());
+      lcekpad.append(cek.copy());
+      while(lcekpad.size() % 8)
+         lcekpad.append(Global_RNG::random(Nonce));
+      return do_rfc3217_wrap(cipher, kek, lcekpad);
+      }
+   else
+      throw Invalid_Argument("CMS_Encoder::wrap: Unknown cipher " + cipher);
+   }
+
+/*************************************************
+* Encode the parameters for an encryption algo   *
+*************************************************/
+SecureVector<byte> CMS_Encoder::encode_params(const std::string& cipher,
+                                              const SymmetricKey& key,
+                                              const InitializationVector& iv)
+   {
+   DER_Encoder encoder;
+
+   if(cipher == "RC2")
+      {
+      encoder.start_sequence();
+      DER::encode(encoder, RC2::EKB_code(8*key.length()));
+      DER::encode(encoder, iv.copy(), OCTET_STRING);
+      encoder.end_sequence();
+      }
+   else if(cipher == "CAST-128")
+      {
+      encoder.start_sequence();
+      DER::encode(encoder, iv.copy(), OCTET_STRING);
+      DER::encode(encoder, 8*key.length());
+      encoder.end_sequence();
+      }
+   else
+      DER::encode(encoder, iv.copy(), OCTET_STRING);
+
+   return encoder.get_contents();
+   }
+
+/*************************************************
+* Generate a CEK or KEK for the cipher           *
+*************************************************/
+SymmetricKey CMS_Encoder::setup_key(const std::string& cipher)
+   {
+   u32bit keysize = 0;
+
+   if(cipher == "TripleDES") keysize = 24;
+   if(cipher == "RC2")       keysize = 16;
+   if(cipher == "CAST-128")  keysize = 16;
+
+   if(keysize == 0)
+      throw Invalid_Argument("CMS: Cannot encrypt with cipher " + cipher);
+
+   SymmetricKey key(keysize);
+   if(cipher == "DES" || cipher == "TripleDES")
+      key.set_odd_parity();
+   return key;
+   }
+
+}