What is AES256 How to Convert in decrypt Processing In Asp.net

AES256 (Advanced Encryption Standard 256-bit) is a symmetric key encryption algorithm used to encrypt and decrypt data. It is a widely used encryption standard for securing sensitive information.

To decrypt data encrypted using AES256 in ASP.NET, you can use the System.Security.Cryptography.Aes class, which is included in the .NET framework.

Here's an example of how you can use the Aes class to decrypt data in ASP.NET:

using System.Security.Cryptography;

// ...

string encryptedText = "encrypted text goes here";
byte[] key = Encoding.UTF8.GetBytes("encryption key goes here");

using (Aes aesAlg = Aes.Create())
{
    aesAlg.Key = key;
    aesAlg.IV = new byte[16]; // use a new IV for each encryption

    // Create a decryptor to perform the stream transform.
    ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

    // Convert the encrypted text to a byte array.
    byte[] encryptedBytes = Convert.FromBase64String(encryptedText);

    // Create the streams used for decryption.
    using (MemoryStream msDecrypt = new MemoryStream(encryptedBytes))
    {
        using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
        {
            using (StreamReader srDecrypt = new StreamReader(csDecrypt))
            {
                // Read the decrypted bytes from the decrypting stream
                // and place them in a string.
                string plaintext = srDecrypt.ReadToEnd();
                
                // Do something with the decrypted plaintext...
            }
        }
    }
}

n this example, you would replace the "encrypted text goes here" placeholder with the actual encrypted text that you want to decrypt. You would also replace the "encryption key goes here" placeholder with the actual encryption key that was used to encrypt the text.

The code creates a new instance of the Aes class, sets the encryption key and initialization vector (IV), and creates a decryptor using the CreateDecryptor method of the Aes class. It then converts the encrypted text to a byte array and creates a CryptoStream to decrypt the data. Finally, it reads the decrypted data from the CryptoStream and places it in a string variable called plaintext, which you can then use as needed.