C# 文字列をAES暗号化 – テックメモ

        private string Encrypt(string plainText)
        {
            // 半角16文字(128bit)、24文字(192bit)、32文字(256bit)から選ぶ。
            byte[] key = Encoding.UTF8.GetBytes(@"u5vwged9ky6y6vii");

            // Block Sizeと同じにする。半角16文字(128bit)
            byte[] iv = Encoding.UTF8.GetBytes(@"8knshgxqy4uf89gq"); 

            byte[] byteValue = Encoding.UTF8.GetBytes(plainText);
            var byteLength = byteValue.Length;

            using (var aes = Aes.Create())
            using (var encryptor = aes.CreateEncryptor(key, iv))
            {
                var encryptValue = encryptor.TransformFinalBlock(byteValue, 0, byteLength);
                var base64Value = Convert.ToBase64String(encryptValue);
                return base64Value;
            }
        }

        public static string Decrypt(string encryptText)
        {
            byte[] key = Encoding.UTF8.GetBytes(@"u5vwged9ky6y6vii");
            byte[] iv = Encoding.UTF8.GetBytes(@"8knshgxqy4uf89gq");

            var byteValue = Convert.FromBase64String(encryptText);
            var byteLength = byteValue.Length;

            using (var aes = Aes.Create())
            using (var decryptor = aes.CreateDecryptor(key, iv))
            {
                var decryptValue = decryptor.TransformFinalBlock(byteValue, 0, byteLength);
                var stringValue = Encoding.UTF8.GetString(decryptValue);
                return stringValue;
            }
        }

private string Encrypt(string plainText)

{

// 半角16文字(128bit)、24文字(192bit)、32文字(256bit)から選ぶ。

byte[] key = Encoding.UTF8.GetBytes(@"u5vwged9ky6y6vii");

// Block Sizeと同じにする。半角16文字(128bit)

byte[] iv = Encoding.UTF8.GetBytes(@"8knshgxqy4uf89gq");

byte[] byteValue = Encoding.UTF8.GetBytes(plainText);

var byteLength = byteValue.Length;

using (var aes = Aes.Create())

using (var encryptor = aes.CreateEncryptor(key, iv))

{

var encryptValue = encryptor.TransformFinalBlock(byteValue, 0, byteLength);

var base64Value = Convert.ToBase64String(encryptValue);

return base64Value;

}

public static string Decrypt(string encryptText)

{

byte[] key = Encoding.UTF8.GetBytes(@"u5vwged9ky6y6vii");

byte[] iv = Encoding.UTF8.GetBytes(@"8knshgxqy4uf89gq");

var byteValue = Convert.FromBase64String(encryptText);

var byteLength = byteValue.Length;

using (var aes = Aes.Create())

using (var decryptor = aes.CreateDecryptor(key, iv))

{

var decryptValue = decryptor.TransformFinalBlock(byteValue, 0, byteLength);

var stringValue = Encoding.UTF8.GetString(decryptValue);

return stringValue;

}