netcore加密填充无效且无法删除

Question

因此，我尝试在 .netcore 下为 Web API 进行加密/解密。 发现这篇文章显示了加密和解密的工作示例。

https://mikaelkoskinen.net/post/encrypt-decrypt-string-asp-net-core

复制并运行，它有效，非常棒——到目前为止。

然后我更改了要加密/解密的字符串，如果因填充问题而失败，则不允许。 EncryptString 和 DecryptString 是逐字记录到网站源代码的。

// THIS IS ORIGINAL and works (without Console.WriteLine)
var content = "Example test";
var key = "E546C8DF278CD5931069B522E695D4F2";
var encrypted = EncryptString(content, key);
var decrypted = DecryptString(encrypted, key);

// Then I changed to encrypt a simple string and fails
content = "testing16charsX1";
encrypted = EncryptString(content, key);
decrypted = DecryptString(encrypted, key);

将函数的原始代码保留在此处的单一源位置。

 public static string EncryptString(string text, string keyString)
        {
            var key = Encoding.UTF8.GetBytes(keyString);

            using (var aesAlg = Aes.Create())
            {
                using (var encryptor = aesAlg.CreateEncryptor(key, aesAlg.IV))
                {
                    using (var msEncrypt = new MemoryStream())
                    {
                        using (var csEncrypt = new CryptoStream(msEncrypt, encryptor, CryptoStreamMode.Write))
                        using (var swEncrypt = new StreamWriter(csEncrypt))
                        {
                            swEncrypt.Write(text);
                        }

                        var iv = aesAlg.IV;

                        var decryptedContent = msEncrypt.ToArray();

                        var result = new byte[iv.Length + decryptedContent.Length];

                        Buffer.BlockCopy(iv, 0, result, 0, iv.Length);
                        Buffer.BlockCopy(decryptedContent, 0, result, iv.Length, decryptedContent.Length);

                        return Convert.ToBase64String(result);
                    }
                }
            }
        }

        public static string DecryptString(string cipherText, string keyString)
        {
            var fullCipher = Convert.FromBase64String(cipherText);

            var iv = new byte[16];
            var cipher = new byte[16];

            Buffer.BlockCopy(fullCipher, 0, iv, 0, iv.Length);
            Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, iv.Length);
            var key = Encoding.UTF8.GetBytes(keyString);

            using (var aesAlg = Aes.Create())
            {
                using (var decryptor = aesAlg.CreateDecryptor(key, iv))
                {
                    string result;
                    using (var msDecrypt = new MemoryStream(cipher))
                    {
                        using (var csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
                        {
                            using (var srDecrypt = new StreamReader(csDecrypt))
                            {
                                result = srDecrypt.ReadToEnd();
                            }
                        }
                    }

                    return result;
                }
            }
        }

感谢帮助。 此外，想要强制执行 AES256 加密/解密，这里没有关于 KeySize 设置为 256 的内容，但想要在不破坏的情况下进行测试，但似乎也被破坏了？

Answer 1

错误就在这里。在

EncryptString

方法中，它依次复制IV和加密内容：

var result = new byte[iv.Length + decryptedContent.Length];
Buffer.BlockCopy(iv, 0, result, 0, iv.Length);
Buffer.BlockCopy(decryptedContent, 0, result, iv.Length, decryptedContent.Length);

但是在

DecryptString

方法中，它只复制了16字节的加密内容：

var iv = new byte[16];
var cipher = new byte[16];
Buffer.BlockCopy(fullCipher, 0, iv, 0, iv.Length);
Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, iv.Length);

它应该复制所有剩余的内容：

var cipher = new byte[fullCipher.Length - iv.Length];
Buffer.BlockCopy(fullCipher, 0, iv, 0, iv.Length);
Buffer.BlockCopy(fullCipher, iv.Length, cipher, 0, cipher.Length);