1 files changed, 110 insertions, 0 deletions
diff --git a/comm/third_party/botan/src/lib/pubkey/mceies/mceies.cpp b/comm/third_party/botan/src/lib/pubkey/mceies/mceies.cpp
new file mode 100644
index 0000000000..4d62889fee
--- /dev/null
+++ b/comm/third_party/botan/src/lib/pubkey/mceies/mceies.cpp
@@ -0,0 +1,110 @@
+/*
+* McEliece Integrated Encryption System
+* (C) 2014,2015 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#include <botan/mceies.h>
+#include <botan/aead.h>
+#include <botan/rng.h>
+#include <botan/mceliece.h>
+#include <botan/pubkey.h>
+
+namespace Botan {
+
+namespace {
+
+secure_vector<uint8_t> aead_key(const secure_vector<uint8_t>& mk,
+                             const AEAD_Mode& aead)
+   {
+   // Fold the key as required for the AEAD mode in use
+   if(aead.valid_keylength(mk.size()))
+      return mk;
+
+   secure_vector<uint8_t> r(aead.key_spec().maximum_keylength());
+   BOTAN_ASSERT_NOMSG(r.size() > 0);
+   for(size_t i = 0; i != mk.size(); ++i)
+      r[i % r.size()] ^= mk[i];
+   return r;
+   }
+
+}
+
+secure_vector<uint8_t>
+mceies_encrypt(const McEliece_PublicKey& pubkey,
+               const uint8_t pt[], size_t pt_len,
+               const uint8_t ad[], size_t ad_len,
+               RandomNumberGenerator& rng,
+               const std::string& algo)
+   {
+   PK_KEM_Encryptor kem_op(pubkey, rng, "KDF1(SHA-512)");
+
+   secure_vector<uint8_t> mce_ciphertext, mce_key;
+   kem_op.encrypt(mce_ciphertext, mce_key, 64, rng);
+
+   const size_t mce_code_bytes = (pubkey.get_code_length() + 7) / 8;
+
+   BOTAN_ASSERT(mce_ciphertext.size() == mce_code_bytes, "Unexpected size");
+
+   std::unique_ptr<AEAD_Mode> aead = AEAD_Mode::create_or_throw(algo, ENCRYPTION);
+
+   const size_t nonce_len = aead->default_nonce_length();
+
+   aead->set_key(aead_key(mce_key, *aead));
+   aead->set_associated_data(ad, ad_len);
+
+   const secure_vector<uint8_t> nonce = rng.random_vec(nonce_len);
+
+   secure_vector<uint8_t> msg(mce_ciphertext.size() + nonce.size() + pt_len);
+   copy_mem(msg.data(), mce_ciphertext.data(), mce_ciphertext.size());
+   copy_mem(msg.data() + mce_ciphertext.size(), nonce.data(), nonce.size());
+   copy_mem(msg.data() + mce_ciphertext.size() + nonce.size(), pt, pt_len);
+
+   aead->start(nonce);
+   aead->finish(msg, mce_ciphertext.size() + nonce.size());
+   return msg;
+   }
+
+secure_vector<uint8_t>
+mceies_decrypt(const McEliece_PrivateKey& privkey,
+               const uint8_t ct[], size_t ct_len,
+               const uint8_t ad[], size_t ad_len,
+               const std::string& algo)
+   {
+   try
+      {
+      Null_RNG null_rng;
+      PK_KEM_Decryptor kem_op(privkey, null_rng, "KDF1(SHA-512)");
+
+      const size_t mce_code_bytes = (privkey.get_code_length() + 7) / 8;
+
+      std::unique_ptr<AEAD_Mode> aead = AEAD_Mode::create_or_throw(algo, DECRYPTION);
+
+      const size_t nonce_len = aead->default_nonce_length();
+
+      if(ct_len < mce_code_bytes + nonce_len + aead->tag_size())
+         throw Decoding_Error("Input message too small to be valid");
+
+      const secure_vector<uint8_t> mce_key = kem_op.decrypt(ct, mce_code_bytes, 64);
+
+      aead->set_key(aead_key(mce_key, *aead));
+      aead->set_associated_data(ad, ad_len);
+
+      secure_vector<uint8_t> pt(ct + mce_code_bytes + nonce_len, ct + ct_len);
+
+      aead->start(&ct[mce_code_bytes], nonce_len);
+      aead->finish(pt, 0);
+      return pt;
+      }
+   catch(Invalid_Authentication_Tag&)
+      {
+      throw;
+      }
+   catch(std::exception& e)
+      {
+      throw Decoding_Error("mce_decrypt failed: " + std::string(e.what()));
+      }
+   }
+
+}