Json.Net 没有内置加密。如果您希望能够在序列化过程中进行加密和解密，您将需要编写一些自定义代码。一种方法是将自定义IContractResolver 与IValueProvider 结合使用。值提供者为您提供了一个钩子，您可以在其中转换序列化过程中的值，而合同解析器使您可以控制何时何地应用值提供者。他们可以一起为您提供您正在寻找的解决方案。
以下是您需要的代码示例。首先，您会注意到我定义了一个新的[JsonEncrypt] 属性；这将用于指示您要加密的属性。 EncryptedStringPropertyResolver 类扩展了 Json.Net 提供的 DefaultContractResolver。我已经覆盖了CreateProperties() 方法，以便我可以检查由基本解析器创建的JsonProperty 对象，并将我的自定义EncryptedStringValueProvider 的一个实例附加到任何应用了[JsonEncrypt] 属性的字符串属性。 EncryptedStringValueProvider 稍后通过各自的 GetValue() 和 SetValue() 方法处理目标字符串属性的实际加密/解密。
using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Security.Cryptography;
using System.Text;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;
[AttributeUsage(AttributeTargets.Property)]
public class JsonEncryptAttribute : Attribute
{
}
public class EncryptedStringPropertyResolver : DefaultContractResolver
{
private byte[] encryptionKeyBytes;
public EncryptedStringPropertyResolver(string encryptionKey)
{
if (encryptionKey == null)
throw new ArgumentNullException("encryptionKey");
// Hash the key to ensure it is exactly 256 bits long, as required by AES-256
using (SHA256Managed sha = new SHA256Managed())
{
this.encryptionKeyBytes =
sha.ComputeHash(Encoding.UTF8.GetBytes(encryptionKey));
}
}
protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
{
IList<JsonProperty> props = base.CreateProperties(type, memberSerialization);
// Find all string properties that have a [JsonEncrypt] attribute applied
// and attach an EncryptedStringValueProvider instance to them
foreach (JsonProperty prop in props.Where(p => p.PropertyType == typeof(string)))
{
PropertyInfo pi = type.GetProperty(prop.UnderlyingName);
if (pi != null && pi.GetCustomAttribute(typeof(JsonEncryptAttribute), true) != null)
{
prop.ValueProvider =
new EncryptedStringValueProvider(pi, encryptionKeyBytes);
}
}
return props;
}
class EncryptedStringValueProvider : IValueProvider
{
PropertyInfo targetProperty;
private byte[] encryptionKey;
public EncryptedStringValueProvider(PropertyInfo targetProperty, byte[] encryptionKey)
{
this.targetProperty = targetProperty;
this.encryptionKey = encryptionKey;
}
// GetValue is called by Json.Net during serialization.
// The target parameter has the object from which to read the unencrypted string;
// the return value is an encrypted string that gets written to the JSON
public object GetValue(object target)
{
string value = (string)targetProperty.GetValue(target);
byte[] buffer = Encoding.UTF8.GetBytes(value);
using (MemoryStream inputStream = new MemoryStream(buffer, false))
using (MemoryStream outputStream = new MemoryStream())
using (AesManaged aes = new AesManaged { Key = encryptionKey })
{
byte[] iv = aes.IV; // first access generates a new IV
outputStream.Write(iv, 0, iv.Length);
outputStream.Flush();
ICryptoTransform encryptor = aes.CreateEncryptor(encryptionKey, iv);
using (CryptoStream cryptoStream = new CryptoStream(outputStream, encryptor, CryptoStreamMode.Write))
{
inputStream.CopyTo(cryptoStream);
}
return Convert.ToBase64String(outputStream.ToArray());
}
}
// SetValue gets called by Json.Net during deserialization.
// The value parameter has the encrypted value read from the JSON;
// target is the object on which to set the decrypted value.
public void SetValue(object target, object value)
{
byte[] buffer = Convert.FromBase64String((string)value);
using (MemoryStream inputStream = new MemoryStream(buffer, false))
using (MemoryStream outputStream = new MemoryStream())
using (AesManaged aes = new AesManaged { Key = encryptionKey })
{
byte[] iv = new byte[16];
int bytesRead = inputStream.Read(iv, 0, 16);
if (bytesRead < 16)
{
throw new CryptographicException("IV is missing or invalid.");
}
ICryptoTransform decryptor = aes.CreateDecryptor(encryptionKey, iv);
using (CryptoStream cryptoStream = new CryptoStream(inputStream, decryptor, CryptoStreamMode.Read))
{
cryptoStream.CopyTo(outputStream);
}
string decryptedValue = Encoding.UTF8.GetString(outputStream.ToArray());
targetProperty.SetValue(target, decryptedValue);
}
}
}
}
一旦您有了解析器，下一步就是将自定义[JsonEncrypt] 属性应用于您希望在序列化期间加密的类中的字符串属性。例如，这是一个可能代表用户的人为类：
public class UserInfo
{
public string UserName { get; set; }
[JsonEncrypt]
public string UserPassword { get; set; }
public string FavoriteColor { get; set; }
[JsonEncrypt]
public string CreditCardNumber { get; set; }
}
最后一步是将自定义解析器注入到序列化过程中。为此，创建一个新的JsonSerializerSettings 实例，然后将ContractResolver 属性设置为自定义解析器的一个新实例。将设置传递给JsonConvert.SerializeObject() 或DeserializeObject() 方法，一切正常。
这是一个往返演示：
public class Program
{
public static void Main(string[] args)
{
try
{
UserInfo user = new UserInfo
{
UserName = "jschmoe",
UserPassword = "Hunter2",
FavoriteColor = "atomic tangerine",
CreditCardNumber = "1234567898765432",
};
// Note: in production code you should not hardcode the encryption
// key into the application-- instead, consider using the Data Protection
// API (DPAPI) to store the key. .Net provides access to this API via
// the ProtectedData class.
JsonSerializerSettings settings = new JsonSerializerSettings();
settings.Formatting = Formatting.Indented;
settings.ContractResolver = new EncryptedStringPropertyResolver("My-Sup3r-Secr3t-Key");
Console.WriteLine("----- Serialize -----");
string json = JsonConvert.SerializeObject(user, settings);
Console.WriteLine(json);
Console.WriteLine();
Console.WriteLine("----- Deserialize -----");
UserInfo user2 = JsonConvert.DeserializeObject<UserInfo>(json, settings);
Console.WriteLine("UserName: " + user2.UserName);
Console.WriteLine("UserPassword: " + user2.UserPassword);
Console.WriteLine("FavoriteColor: " + user2.FavoriteColor);
Console.WriteLine("CreditCardNumber: " + user2.CreditCardNumber);
}
catch (Exception ex)
{
Console.WriteLine(ex.GetType().Name + ": " + ex.Message);
}
}
}
输出：
----- Serialize -----
{
"UserName": "jschmoe",
"UserPassword": "sK2RvqT6F61Oib1ZittGBlv8xgylMEHoZ+1TuOeYhXQ=",
"FavoriteColor": "atomic tangerine",
"CreditCardNumber": "qz44JVAoJEFsBIGntHuPIgF1sYJ0uyYSCKdYbMzrmfkGorxgZMx3Uiv+VNbIrbPR"
}
----- Deserialize -----
UserName: jschmoe
UserPassword: Hunter2
FavoriteColor: atomic tangerine
CreditCardNumber: 1234567898765432
小提琴：https://dotnetfiddle.net/trsiQc