Add an AES implementation with openssl evp

1 files changed, 111 insertions, 0 deletions

diff --git a/src/crypt/cryptaes.cpp b/src/crypt/cryptaes.cpp
new file mode 100644
index 0000000..b74ae03
--- /dev/null
+++ b/src/crypt/cryptaes.cpp
@@ -0,0 +1,111 @@
+#include "cryptaes.h"
+
+CryptAes::CryptAes()
+    : CryptClassEvp()
+{
+    m_iv = QByteArray(16, 0);
+}
+
+const EVP_CIPHER *CryptAes::algorithm()
+{
+    switch (m_keyLength)
+    {
+    case 128:
+
+        return EVP_aes_128_cbc();
+        break;
+
+    case 192:
+
+        return EVP_aes_192_cbc();
+        break;
+
+    case 256:
+
+        return EVP_aes_256_cbc();
+        break;
+    }
+
+    return EVP_enc_null();
+}
+
+
+void CryptAes::encrypt()
+{
+    EVP_MD_CTX *ctx;
+
+    /* Create and initialise the context */
+    if (!(ctx = EVP_MD_CTX_create()))
+    {
+        handleOpenSslError();
+    }
+
+    /* Initialise the encryption operation. IMPORTANT - ensure you use a key
+     * and IV size appropriate for your cipher */
+    if (1 != EVP_DigestInit_ex(ctx, EVP_sha256(), NULL))
+    {
+        handleOpenSslError();
+    }
+
+    /* Provide the message to be encrypted, and obtain the encrypted output.
+     * EVP_EncryptUpdate can be called multiple times if necessary
+     */
+    if (1 != EVP_DigestUpdate(ctx, m_key.data(), m_key.size()))
+    {
+        handleOpenSslError();
+    }
+
+    m_key = QByteArray(256, 0);
+
+    /* Finalise the encryption. Further ciphertext bytes may be written at
+     * this stage.
+     */
+    if (1 != EVP_DigestFinal_ex(ctx, (unsigned char *) m_key.data(), NULL))
+    {
+        handleOpenSslError();
+    }
+
+    EVP_MD_CTX_destroy(ctx);
+
+    CryptClassEvp::encrypt();
+}
+
+void CryptAes::decrypt()
+{
+    EVP_MD_CTX *ctx;
+
+    /* Create and initialise the context */
+    if (!(ctx = EVP_MD_CTX_create()))
+    {
+        handleOpenSslError();
+    }
+
+    /* Initialise the encryption operation. IMPORTANT - ensure you use a key
+     * and IV size appropriate for your cipher */
+    if (1 != EVP_DigestInit_ex(ctx, EVP_sha256(), NULL))
+    {
+        handleOpenSslError();
+    }
+
+    /* Provide the message to be encrypted, and obtain the encrypted output.
+     * EVP_EncryptUpdate can be called multiple times if necessary
+     */
+    if (1 != EVP_DigestUpdate(ctx, m_key.data(), m_key.size()))
+    {
+        handleOpenSslError();
+    }
+
+    m_key = QByteArray(256, 0);
+
+    /* Finalise the encryption. Further ciphertext bytes may be written at
+     * this stage.
+     */
+    if (1 != EVP_DigestFinal_ex(ctx, (unsigned char *) m_key.data(), NULL))
+    {
+        handleOpenSslError();
+    }
+
+    EVP_MD_CTX_destroy(ctx);
+
+    CryptClassEvp::decrypt();
+}