C# 中的 Aes 加密 使用其他 IV 解密

Question

They say you can decrypt the data by using the same secret key but another Initialization Vector, How to achieve that one? Example: My IV for encryption is as follows byte[] bytes = {12,12,5,12,32,62,91,16,89,92,17,72,45,52,13,42}; but for my Decryption is random IV that is 16bytes in length.

Answer 1

You need to call SymmetricAlgorithm.CreateDecryptor() with the same IV that was used for encrypting.

Quoting from the docs :

The SymmetricAlgorithm.CreateDecryptor method from the Aes instance is passed the IV value and the same key that was used for encryption.

Code sample, also from docs page:

Aes aes = Aes.Create();
CryptoStream cryptStream = new CryptoStream(
    fileStream,
    aes.CreateDecryptor(key, iv),
    CryptoStreamMode.Read
);