C# AES encryption and decryption, custom key, offset and encryption mode

encryption

/// <summary>
        /// AES加密
        /// </summary>
        /// <param name="source"></param>
        /// <param name="key">密钥</param>
        /// <param name="iv">初始向量</param>
        /// <param name="padding">填充模式</param>
        /// <param name="mode">加密模式</param>
        /// <returns></returns>
        public static (bool isOk, string text) AESEncrypt(this string source, string key, string iv = "", PaddingMode padding = PaddingMode.PKCS7, CipherMode mode = CipherMode.CBC)
        {
            try
            {
                byte[] keyBytes = Encoding.UTF8.GetBytes(key);
                byte[] textBytes = Encoding.UTF8.GetBytes(source);
                byte[] ivBytes = Encoding.UTF8.GetBytes(iv);

                byte[] useKeyBytes = new byte[16];
                byte[] useIvBytes = new byte[16];

                if (keyBytes.Length > useKeyBytes.Length)
                    Array.Copy(keyBytes, useKeyBytes, useKeyBytes.Length);
                else
                    Array.Copy(keyBytes, useKeyBytes, keyBytes.Length);

                if (ivBytes.Length > useIvBytes.Length)
                    Array.Copy(ivBytes, useIvBytes, useIvBytes.Length);
                else
                    Array.Copy(ivBytes, useIvBytes, ivBytes.Length);

                Aes aes = System.Security.Cryptography.Aes.Create();
                aes.KeySize = 256;//秘钥的大小，以位为单位,128,256等
                aes.BlockSize = 128;//支持的块大小
                aes.Padding = padding;//填充模式
                aes.Mode = mode;
                aes.Key = useKeyBytes;
                aes.IV = useIvBytes;//初始化向量，如果没有设置默认的16个0

                ICryptoTransform cryptoTransform = aes.CreateEncryptor();
                byte[] resultBytes = cryptoTransform.TransformFinalBlock(textBytes, 0, textBytes.Length);

                return (true, Convert.ToBase64String(resultBytes));
            }
            catch (Exception ex)
            {
                return (false, ex.Message);
            }
        }

Decrypt

/// <summary>
        /// AES解密
        /// </summary>
        /// <param name="source"></param>
        /// <param name="key">密钥</param>
        /// <param name="iv">初始向量</param>
        /// <param name="padding">填充模式</param>
        /// <param name="mode">加密模式</param>
        /// <returns></returns>
        public static (bool isOk, string text) AESDecrypt(this string source, string key, string iv = "", PaddingMode padding = PaddingMode.PKCS7, CipherMode mode = CipherMode.CBC)
        {
            try
            {
                byte[] keyBytes = Encoding.UTF8.GetBytes(key);
                byte[] textBytes = Convert.FromBase64String(source);
                byte[] ivBytes = Encoding.UTF8.GetBytes(iv);

                byte[] useKeyBytes = new byte[16];
                byte[] useIvBytes = new byte[16];

                if (keyBytes.Length > useKeyBytes.Length)
                    Array.Copy(keyBytes, useKeyBytes, useKeyBytes.Length);
                else
                    Array.Copy(keyBytes, useKeyBytes, keyBytes.Length);

                if (ivBytes.Length > useIvBytes.Length)
                    Array.Copy(ivBytes, useIvBytes, useIvBytes.Length);
                else
                    Array.Copy(ivBytes, useIvBytes, ivBytes.Length);

                Aes aes = System.Security.Cryptography.Aes.Create();
                aes.KeySize = 256;//秘钥的大小，以位为单位,128,256等
                aes.BlockSize = 128;//支持的块大小
                aes.Padding = padding;//填充模式
                aes.Mode = mode;
                aes.Key = useKeyBytes;
                aes.IV = useIvBytes;//初始化向量，如果没有设置默认的16个0

                ICryptoTransform decryptoTransform = aes.CreateDecryptor();
                byte[] resultBytes = decryptoTransform.TransformFinalBlock(textBytes, 0, textBytes.Length);

                return (true, Encoding.UTF8.GetString(resultBytes));
            }
            catch (Exception ex)
            {
                return (false, ex.Message);
            }
        }