namespace System.Security.Cryptography
{
    // Note for discussion: Should this be sealed or unsealed?
    public sealed class AuthenticationTagMismatchException : CryptographicException
    {
        public AuthenticationTagMismatchException();
        public AuthenticationTagMismatchException(string? message);
        public AuthenticationTagMismatchException(string? message, Exception? innerException);
    }
}

// User has provided password, and PBKDF was used to derive key.
using (var aesGcm = new AesGcm(key))
{
    try
    {
        aesGcm.Decrypt(iv, ciphertext, tag, plaintext);
    }
    catch (AuthenticationTagMismatchException)
    {
        // Notify user that password was incorrect or data was corrupt.
        // Prompt user for password again in case user typo'd password.
    }
    catch (CryptographicException)
    {
        // Notify the user that decryption failed.
    }
}