McEliece cleanups

Remove and consolidate various headers

Reduce memory usage of GF2m_Field by sharing the log and exponent
tables across all instances of a particular word size.

Remove McEliece_Public_Operation and McEliece_Private_Operation which
were difficult to use safely. Instead only the KEM operations are exposed.

Add McEliece_PublicKey::random_plaintext_element

Add command line `mce` tool and some McEliece documentation

Convert the speed program to check McEliece keys of the suggested size

Add McEliece KATs for both key generation and KEM

Fix HMAC_DRBG constructor which derefed a pointer before its time

2 files changed, 19 insertions, 18 deletions

diff --git a/src/lib/pubkey/mceies/mceies.cpp b/src/lib/pubkey/mceies/mceies.cpp
index 58dde2e27..d4d956a54 100644
--- a/src/lib/pubkey/mceies/mceies.cpp
+++ b/src/lib/pubkey/mceies/mceies.cpp
@@ -31,9 +31,10 @@ secure_vector<byte> aead_key(const secure_vector<byte>& mk,
 
 secure_vector<byte>
 mceies_encrypt(const McEliece_PublicKey& pubkey,
-               const secure_vector<byte>& pt,
-               byte ad[], size_t ad_len,
-               RandomNumberGenerator& rng)
+               const byte pt[], size_t pt_len,
+               const byte ad[], size_t ad_len,
+               RandomNumberGenerator& rng,
+               const std::string& algo)
    {
    McEliece_KEM_Encryptor kem_op(pubkey);
 
@@ -45,7 +46,6 @@ mceies_encrypt(const McEliece_PublicKey& pubkey,
 
    BOTAN_ASSERT(mce_ciphertext.size() == mce_code_bytes, "Unexpected size");
 
-   const std::string algo = "AES-256/OCB";
    std::unique_ptr<AEAD_Mode> aead(get_aead(algo, ENCRYPTION));
    if(!aead)
       throw std::runtime_error("mce_encrypt unable to create AEAD instance '" + algo + "'");
@@ -57,10 +57,10 @@ mceies_encrypt(const McEliece_PublicKey& pubkey,
 
    const secure_vector<byte> nonce = rng.random_vec(nonce_len);
 
-   secure_vector<byte> msg(mce_ciphertext.size() + nonce.size() + pt.size());
+   secure_vector<byte> 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.data(), pt.size());
+   copy_mem(msg.data() + mce_ciphertext.size() + nonce.size(), pt, pt_len);
 
    aead->start(nonce);
    aead->finish(msg, mce_ciphertext.size() + nonce.size());
@@ -69,8 +69,9 @@ mceies_encrypt(const McEliece_PublicKey& pubkey,
 
 secure_vector<byte>
 mceies_decrypt(const McEliece_PrivateKey& privkey,
-               const secure_vector<byte>& ct,
-               byte ad[], size_t ad_len)
+               const byte ct[], size_t ct_len,
+               const byte ad[], size_t ad_len,
+               const std::string& algo)
    {
    try
       {
@@ -78,23 +79,21 @@ mceies_decrypt(const McEliece_PrivateKey& privkey,
 
       const size_t mce_code_bytes = (privkey.get_code_length() + 7) / 8;
 
-
-      const std::string algo = "AES-256/OCB";
       std::unique_ptr<AEAD_Mode> aead(get_aead(algo, DECRYPTION));
       if(!aead)
          throw std::runtime_error("Unable to create AEAD instance '" + algo + "'");
 
       const size_t nonce_len = aead->default_nonce_length();
 
-      if(ct.size() < mce_code_bytes + nonce_len + aead->tag_size())
+      if(ct_len < mce_code_bytes + nonce_len + aead->tag_size())
          throw std::runtime_error("Input message too small to be valid");
 
-      const secure_vector<byte> mce_key = kem_op.decrypt(ct.data(), mce_code_bytes);
+      const secure_vector<byte> mce_key = kem_op.decrypt(ct, mce_code_bytes);
 
       aead->set_key(aead_key(mce_key, *aead));
       aead->set_associated_data(ad, ad_len);
 
-      secure_vector<byte> pt(ct.begin() + mce_code_bytes + nonce_len, ct.end());
+      secure_vector<byte> pt(ct + mce_code_bytes + nonce_len, ct + ct_len);
 
       aead->start(&ct[mce_code_bytes], nonce_len);
       aead->finish(pt, 0);
diff --git a/src/lib/pubkey/mceies/mceies.h b/src/lib/pubkey/mceies/mceies.h
index 9ead21a17..b43e2065f 100644
--- a/src/lib/pubkey/mceies/mceies.h
+++ b/src/lib/pubkey/mceies/mceies.h
@@ -23,9 +23,10 @@ class McEliece_PrivateKey;
 */
 secure_vector<byte>
 BOTAN_DLL mceies_encrypt(const McEliece_PublicKey& pubkey,
-                         const secure_vector<byte>& pt,
-                         byte ad[], size_t ad_len,
-                         RandomNumberGenerator& rng);
+                         const byte pt[], size_t pt_len,
+                         const byte ad[], size_t ad_len,
+                         RandomNumberGenerator& rng,
+                         const std::string& aead = "AES-256/OCB");
 
 /**
 * McEliece Integrated Encryption System
@@ -34,8 +35,9 @@ BOTAN_DLL mceies_encrypt(const McEliece_PublicKey& pubkey,
 */
 secure_vector<byte>
 BOTAN_DLL mceies_decrypt(const McEliece_PrivateKey& privkey,
-                         const secure_vector<byte>& ct,
-                         byte ad[], size_t ad_len);
+                         const byte ct[], size_t ct_len,
+                         const byte ad[], size_t ad_len,
+                         const std::string& aead = "AES-256/OCB");
 
 
 }