Creating an AES 256 block cipher

Question

My NAS Cloud drive in amid of being reformatted. What I want to perform, afterwards, is to create an AES-256 block cipher.

It would be either a folder or an icon, which enables to prompt me to sign in my own created credentials using AES-256 encryption standard.

How would I perform this properly by using the right algorithms?

Regards,

JohnCTX

Answer 1

Hi @JohnCTX ,

I created a C++/CLR project, it uses AES 256, can encrypt and decrypt strings, you could use it to encrypt file names, the following is my code, you could refer to it.

private: array<unsigned char>^ AES_Encrypt(array<unsigned char>^ bytesToBeEncrypted, array<unsigned char>^ passwordBytes) {  
        array<unsigned char>^ encryptedBytes = nullptr;  
        array<unsigned char>^ saltBytes = gcnew array<unsigned char>(8) { 1, 2, 3, 4, 5, 6, 7, 8 };  
        MemoryStream^ ms = gcnew MemoryStream();  
        RijndaelManaged^ AES = gcnew RijndaelManaged();  
        AES->KeySize = 256;  
        AES->BlockSize = 128;  
        AES->Mode = CipherMode::CBC;  
        AES->Padding = System::Security::Cryptography::PaddingMode::Zeros;  
        auto key = gcnew Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);  
        AES->Key = key->GetBytes(AES->KeySize / 8);  
        AES->IV = key->GetBytes(AES->BlockSize / 8);  
        auto cs = gcnew CryptoStream(ms, AES->CreateEncryptor(), CryptoStreamMode::Write);  
        try {              
                try {  
                    cs->Write(bytesToBeEncrypted, 0, bytesToBeEncrypted->Length);  
                    cs->Close();  
                }  
                finally {  
                    if (cs != nullptr) delete cs;  
                }  
                encryptedBytes = ms->ToArray();           
        }  
        finally {  
            if (ms != nullptr) delete ms;  
        }  
        return encryptedBytes;  
    }  
    private: array<unsigned char>^ AES_Decrypt(array<unsigned char>^ bytesToBeDecrypted, array<unsigned char>^ passwordBytes) {  
        array<unsigned char>^ decryptedBytes = nullptr;  
        array<unsigned char>^ saltBytes = gcnew array<unsigned char>(8) { 1, 2, 3, 4, 5, 6, 7, 8 };  
        MemoryStream^ ms = gcnew MemoryStream();  
        RijndaelManaged^ AES = gcnew RijndaelManaged();  
        AES->KeySize = 256;  
        AES->BlockSize = 128;  
        AES->Mode = CipherMode::CBC;  
        AES->Padding = System::Security::Cryptography::PaddingMode::Zeros;  
        auto key = gcnew Rfc2898DeriveBytes(passwordBytes, saltBytes, 1000);  
        AES->Key = key->GetBytes(AES->KeySize / 8);  
        AES->IV = key->GetBytes(AES->BlockSize / 8);        
        auto cs = gcnew CryptoStream(ms, AES->CreateDecryptor(), CryptoStreamMode::Write);  
        try {      
                try {  
                    cs->Write(bytesToBeDecrypted, 0, bytesToBeDecrypted->Length);  
                    cs->Close();  
                }  
                finally {  
                    if (cs != nullptr) delete cs;  
                }  
                decryptedBytes = ms->ToArray();  
            }        
        finally {  
            if (ms != nullptr) delete ms;  
        }  
        return decryptedBytes;  
    }  
           //Encrypt String  
    private: System::String^ EncryptText(System::String^ input, System::String^ password) {  
        array<unsigned char>^ bytesToBeEncrypted = System::Text::Encoding::UTF8->GetBytes(input);  
        array<unsigned char>^ passwordBytes = System::Text::Encoding::UTF8->GetBytes(password);  
        passwordBytes = SHA256::Create()->ComputeHash(passwordBytes);  
        array<unsigned char>^ bytesEncrypted = AES_Encrypt(bytesToBeEncrypted, passwordBytes);  
        System::String^ result = Convert::ToBase64String(bytesEncrypted);  
        return result;  
    }  
           //Decrypt String  
    private: System::String^ DecryptText(System::String^ input, System::String^ password) {  
        array<unsigned char>^ bytesToBeDecrypted = Convert::FromBase64String(input);  
        array<unsigned char>^ passwordBytes = System::Text::Encoding::Encoding::UTF8->GetBytes(password);  
        passwordBytes = SHA256::Create()->ComputeHash(passwordBytes);  
        array<unsigned char>^ bytesDecrypted = AES_Decrypt(bytesToBeDecrypted, passwordBytes);  
        System::String^ result = System::Text::Encoding::Encoding::UTF8->GetString(bytesDecrypted);  
        return result;  
    }  
#pragma endregion  
    private: System::Void button1_Click(System::Object^ sender, System::EventArgs^ e) {  
  
        System::String^ temp = EncryptText(this->textBox1->Text, "batman");  
        this->label1->Text = temp;  
        this->label2->Text = DecryptText(temp, "batman");  
    }  

Best regards,

Elya

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