If you are decrypting data using the Rijndael encryption algorithm in C# and getting a 16-character response, it's possible that the decrypted data is in a byte array format, and you are converting it directly to a string. When you convert binary data to a string, it might not display as expected if the data contains non-printable characters.
To handle this, you should first convert the decrypted byte array to a valid string format using an appropriate character encoding, such as UTF-8. Here's an example of how to do this:
```csharp
using System;
using System.Security.Cryptography;
using System.Text;
// Your encrypted data as a byte array
byte[] encryptedData = ...;
// Rijndael decryption
using (Rijndael rijAlg = Rijndael.Create())
{
// Set your decryption key and IV
using (ICryptoTransform decryptor = rijAlg.CreateDecryptor())
{
using (MemoryStream msDecrypt = new MemoryStream(encryptedData))
{
using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
{
using (StreamReader sr = new StreamReader(csDecrypt, Encoding.UTF8))
{
// Read the decrypted data as a string
string decryptedString = sr.ReadToEnd();
Console.WriteLine(decryptedString);
}
}
}
}
}
```
Ensure that you set the correct key and IV for your decryption process. The `Encoding.UTF8` argument in the `StreamReader` constructor is important for converting the decrypted bytes to a readable string.