1 files changed, 81 insertions, 0 deletions
diff --git a/src/lib/pubkey/keypair/keypair.cpp b/src/lib/pubkey/keypair/keypair.cpp
new file mode 100644
index 000000000..a8631062d
--- /dev/null
+++ b/src/lib/pubkey/keypair/keypair.cpp
@@ -0,0 +1,81 @@
+/*
+* Keypair Checks
+* (C) 1999-2010 Jack Lloyd
+*
+* Distributed under the terms of the Botan license
+*/
+
+#include <botan/keypair.h>
+#include <botan/pubkey.h>
+
+namespace Botan {
+
+namespace KeyPair {
+
+/*
+* Check an encryption key pair for consistency
+*/
+bool encryption_consistency_check(RandomNumberGenerator& rng,
+                                  const Private_Key& key,
+                                  const std::string& padding)
+   {
+   PK_Encryptor_EME encryptor(key, padding);
+   PK_Decryptor_EME decryptor(key, padding);
+
+   /*
+   Weird corner case, if the key is too small to encrypt anything at
+   all. This can happen with very small RSA keys with PSS
+   */
+   if(encryptor.maximum_input_size() == 0)
+      return true;
+
+   std::vector<byte> plaintext =
+      unlock(rng.random_vec(encryptor.maximum_input_size() - 1));
+
+   std::vector<byte> ciphertext = encryptor.encrypt(plaintext, rng);
+   if(ciphertext == plaintext)
+      return false;
+
+   std::vector<byte> decrypted = unlock(decryptor.decrypt(ciphertext));
+
+   return (plaintext == decrypted);
+   }
+
+/*
+* Check a signature key pair for consistency
+*/
+bool signature_consistency_check(RandomNumberGenerator& rng,
+                                 const Private_Key& key,
+                                 const std::string& padding)
+   {
+   PK_Signer signer(key, padding);
+   PK_Verifier verifier(key, padding);
+
+   std::vector<byte> message = unlock(rng.random_vec(16));
+
+   std::vector<byte> signature;
+
+   try
+      {
+      signature = signer.sign_message(message, rng);
+      }
+   catch(Encoding_Error)
+      {
+      return false;
+      }
+
+   if(!verifier.verify_message(message, signature))
+      return false;
+
+   // Now try to check a corrupt signature, ensure it does not succeed
+   ++message[0];
+
+   if(verifier.verify_message(message, signature))
+      return false;
+
+   return true;
+   }
+
+}
+
+}