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-rw-r--r--src/PolarSSL++/AesCfb128Decryptor.cpp67
1 files changed, 67 insertions, 0 deletions
diff --git a/src/PolarSSL++/AesCfb128Decryptor.cpp b/src/PolarSSL++/AesCfb128Decryptor.cpp
new file mode 100644
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+++ b/src/PolarSSL++/AesCfb128Decryptor.cpp
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+
+// AesCfb128Decryptor.cpp
+
+// Implements the cAesCfb128Decryptor class decrypting data using AES CFB-128
+
+#include "Globals.h"
+#include "AesCfb128Decryptor.h"
+
+
+
+
+
+cAesCfb128Decryptor::cAesCfb128Decryptor(void) :
+ m_IVOffset(0),
+ m_IsValid(false)
+{
+}
+
+
+
+
+
+cAesCfb128Decryptor::~cAesCfb128Decryptor()
+{
+ // Clear the leftover in-memory data, so that they can't be accessed by a backdoor
+ memset(&m_Aes, 0, sizeof(m_Aes));
+}
+
+
+
+
+
+void cAesCfb128Decryptor::Init(const Byte a_Key[16], const Byte a_IV[16])
+{
+ ASSERT(!IsValid()); // Cannot Init twice
+
+ memcpy(m_IV, a_IV, 16);
+ aes_setkey_enc(&m_Aes, a_Key, 128);
+ m_IsValid = true;
+}
+
+
+
+
+
+void cAesCfb128Decryptor::ProcessData(Byte * a_DecryptedOut, const Byte * a_EncryptedIn, size_t a_Length)
+{
+ ASSERT(IsValid()); // Must Init() first
+
+ // PolarSSL doesn't support AES-CFB8, need to implement it manually:
+ for (size_t i = 0; i < a_Length; i++)
+ {
+ Byte Buffer[sizeof(m_IV)];
+ aes_crypt_ecb(&m_Aes, AES_ENCRYPT, m_IV, Buffer);
+ for (size_t idx = 0; idx < sizeof(m_IV) - 1; idx++)
+ {
+ m_IV[idx] = m_IV[idx + 1];
+ }
+ m_IV[sizeof(m_IV) - 1] = a_EncryptedIn[i];
+ a_DecryptedOut[i] = a_EncryptedIn[i] ^ Buffer[0];
+ }
+}
+
+
+
+
+