Add ctaes-based constant time AES implementation

src/crypto/aes.cpp

@@ -0,0 +1,73 @@
+// Copyright (c) 2016 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "aes.h"
+#include "crypto/common.h"
+
+#include <assert.h>
+#include <string.h>
+
+extern "C" {
+#include "crypto/ctaes/ctaes.c"
+}
+
+AES128Encrypt::AES128Encrypt(const unsigned char key[16])
+{
+    AES128_init(&ctx, key);
+}
+
+AES128Encrypt::~AES128Encrypt()
+{
+    memset(&ctx, 0, sizeof(ctx));
+}
+
+void AES128Encrypt::Encrypt(unsigned char ciphertext[16], const unsigned char plaintext[16]) const
+{
+    AES128_encrypt(&ctx, 1, ciphertext, plaintext);
+}
+
+AES128Decrypt::AES128Decrypt(const unsigned char key[16])
+{
+    AES128_init(&ctx, key);
+}
+
+AES128Decrypt::~AES128Decrypt()
+{
+    memset(&ctx, 0, sizeof(ctx));
+}
+
+void AES128Decrypt::Decrypt(unsigned char plaintext[16], const unsigned char ciphertext[16]) const
+{
+    AES128_decrypt(&ctx, 1, plaintext, ciphertext);
+}
+
+AES256Encrypt::AES256Encrypt(const unsigned char key[32])
+{
+    AES256_init(&ctx, key);
+}
+
+AES256Encrypt::~AES256Encrypt()
+{
+    memset(&ctx, 0, sizeof(ctx));
+}
+
+void AES256Encrypt::Encrypt(unsigned char ciphertext[16], const unsigned char plaintext[16]) const
+{
+    AES256_encrypt(&ctx, 1, ciphertext, plaintext);
+}
+
+AES256Decrypt::AES256Decrypt(const unsigned char key[32])
+{
+    AES256_init(&ctx, key);
+}
+
+AES256Decrypt::~AES256Decrypt()
+{
+    memset(&ctx, 0, sizeof(ctx));
+}
+
+void AES256Decrypt::Decrypt(unsigned char plaintext[16], const unsigned char ciphertext[16]) const
+{
+    AES256_decrypt(&ctx, 1, plaintext, ciphertext);
+}