Add an AES implementation with openssl evp

7 files changed, 144 insertions, 8 deletions

diff --git a/IT-Sicherheit_SS2015_BaseProject.pro b/IT-Sicherheit_SS2015_BaseProject.pro
index efbfe13..2fbf22f 100644
--- a/IT-Sicherheit_SS2015_BaseProject.pro
+++ b/IT-Sicherheit_SS2015_BaseProject.pro
@@ -29,7 +29,8 @@ SOURCES +=  src/main.cpp \
     src/crypt/cryptclasscaesar.cpp \
     src/crypt/cryptclassrc4.cpp \
     src/crypt/cryptrc4.cpp \
-    src/crypt/cryptclassevp.cpp
+    src/crypt/cryptclassevp.cpp \
+    src/crypt/cryptaes.cpp
 
 HEADERS  += src/mainwindow.h \
             src/tabwidgetselectalgorithm.h \
@@ -46,7 +47,8 @@ HEADERS  += src/mainwindow.h \
     src/crypt/cryptclasscaesar.h \
     src/crypt/cryptclassrc4.h \
     src/crypt/cryptrc4.h \
-    src/crypt/cryptclassevp.h
+    src/crypt/cryptclassevp.h \
+    src/crypt/cryptaes.h
 
 FORMS    += src/forms/mainwindow.ui \
             src/forms/tabsymmetric.ui \
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();
+}
diff --git a/src/crypt/cryptaes.h b/src/crypt/cryptaes.h
new file mode 100644
index 0000000..58ddba1
--- /dev/null
+++ b/src/crypt/cryptaes.h
@@ -0,0 +1,21 @@
+#ifndef CRYPTAES_H
+#define CRYPTAES_H
+
+#include "cryptclassevp.h"
+
+#include <QDebug>
+
+class CryptAes : public CryptClassEvp
+{
+public:
+    CryptAes();
+
+    // CryptClassEvp interface
+public:
+    virtual const EVP_CIPHER *algorithm();
+
+    virtual void encrypt();
+    virtual void decrypt();
+};
+
+#endif // CRYPTAES_H
diff --git a/src/crypt/cryptclassbase.cpp b/src/crypt/cryptclassbase.cpp
index 88f99a1..ac4a812 100644
--- a/src/crypt/cryptclassbase.cpp
+++ b/src/crypt/cryptclassbase.cpp
@@ -10,6 +10,7 @@ CryptClassBase::~CryptClassBase()
     m_cryptText.fill(0);
     m_clearText.fill(0);
     m_binaryData = false;
+    m_keyLength = 0;
 }
 
 void CryptClassBase::generateRandomKey()
diff --git a/src/crypt/cryptclassevp.cpp b/src/crypt/cryptclassevp.cpp
index 1ee09a0..7aec7b6 100644
--- a/src/crypt/cryptclassevp.cpp
+++ b/src/crypt/cryptclassevp.cpp
@@ -19,9 +19,9 @@ void CryptClassEvp::encrypt()
 
     EVP_CIPHER_CTX *ctx;
 
-    int len;
+    int len = 0;
 
-    int ciphertext_len;
+    int ciphertext_len = 0;
 
     /* Create and initialise the context */
     if (!(ctx = EVP_CIPHER_CTX_new()))
@@ -58,6 +58,7 @@ void CryptClassEvp::encrypt()
 
     ciphertext_len += len;
 
+    m_cryptText.resize(ciphertext_len);
     /* Clean up */
     EVP_CIPHER_CTX_free(ctx);
 }
@@ -104,7 +105,7 @@ void CryptClassEvp::decrypt()
     }
 
     plaintext_len += len;
-
+    m_clearText.resize(plaintext_len);
     /* Clean up */
     EVP_CIPHER_CTX_free(ctx);
 }
diff --git a/src/crypt/cryptengine.cpp b/src/crypt/cryptengine.cpp
index 3e620a6..fcee6f2 100644
--- a/src/crypt/cryptengine.cpp
+++ b/src/crypt/cryptengine.cpp
@@ -114,8 +114,8 @@ void CryptEngine::oncipherSelected_triggered(int cipher)
     }
     else if( algorithm == "AES" )
     {
-//        delete m_cryptClass;
-//        m_cryptClass = new CryptClassAES;
+        delete m_cryptClass;
+        m_cryptClass = new CryptAes;
         qDebug("CryptEngine::oncipherSelected_triggered - AES");
     }
     else if( algorithm == "RSA" )
diff --git a/src/crypt/cryptengine.h b/src/crypt/cryptengine.h
index df91599..50f91a1 100644
--- a/src/crypt/cryptengine.h
+++ b/src/crypt/cryptengine.h
@@ -9,7 +9,7 @@
 #include "cryptclasscaesar.h"
 #include "cryptclassrc4.h"
 //#include "cryptclasscube.h"
-//#include "cryptclassaes.h"
+#include "cryptaes.h"
 //#include "cryptclassrsa.h"
 //#include "cryptclassecc.h"