针对具有X509证书的多个收件人的XML加密和解密

本文关键字：XML 收件人 加密 解密 X509 证书 | 更新日期: 2023-09-27 18:20:46

我已经使用MSDN上的示例对xml文档进行了加密和解密。http://msdn.microsoft.com/en-us/library/ms229744.aspx和http://msdn.microsoft.com/en-us/library/ms229943.aspx

这一切都是根据W3C XML加密标准（XMLEnc）完成的。

一切都很好。我的问题是，一个xml文档是为2或3个收件人准备的。我想用多个密钥（X509证书公钥）加密同一个xml，这样文档就可以由多个收件人解密。

根据W3C XML加密标准，通过使用包含加密对称会话密钥的多个EncryptionKey元素，这一切都是可能的。

我找不到任何关于如何使用标准加密类在.Net中实现这一点的示例。

这必须在.NET C#中实现。

有没有办法做到这一点或在某个地方编写示例代码？

针对具有X509证书的多个收件人的XML加密和解密

EncryptedElement类可以接受任意数量的EncryptedKey。只要对方能够正确识别他们的加密密钥（使用Recipient或KeyInfoName元素），你就不会有任何问题： 
// example xml
XmlDocument xdoc = new XmlDocument();
xdoc.PreserveWhitespace = true;
xdoc.LoadXml(@"<root><encryptme>hello world</encryptme></root>");
var elementToEncrypt = (XmlElement)xdoc.GetElementsByTagName("encryptme")[0];
// keys
// rsa keys would normally be pulled from a store
RSA rsaKey1 = new RSACryptoServiceProvider();
RSA rsaKey2 = new RSACryptoServiceProvider();
var publicKeys = new[] { rsaKey1, rsaKey2 };
string sessKeyName = "helloworldkey";
var sessKey = new RijndaelManaged() { KeySize = 256 };
// encrypt
var encXml = new EncryptedXml();
var encryptedElement = new EncryptedData()
{
    Type = EncryptedXml.XmlEncElementUrl,
    EncryptionMethod = new EncryptionMethod(EncryptedXml.XmlEncAES256Url),
    KeyInfo = new KeyInfo()
};
encryptedElement.CipherData.CipherValue = encXml.EncryptData(elementToEncrypt, sessKey, false);
encryptedElement.KeyInfo.AddClause(new KeyInfoName(sessKeyName));
// encrypt the session key and add keyinfo's
int keyID = 0;
foreach (var pk in publicKeys)
{
    var encKey = new EncryptedKey()
    {
        CipherData = new CipherData(EncryptedXml.EncryptKey(sessKey.Key, pk, false)),
        EncryptionMethod = new EncryptionMethod(EncryptedXml.XmlEncRSA15Url),
        Recipient = string.Format("recipient{0}@foobar.com", ++keyID),
        CarriedKeyName = sessKeyName,
    };
    encKey.KeyInfo.AddClause(new KeyInfoName(encKey.Recipient));
    encryptedElement.KeyInfo.AddClause(new KeyInfoEncryptedKey(encKey));
}
// update the xml
EncryptedXml.ReplaceElement(elementToEncrypt, encryptedElement, false);
// show the result
Console.Write(xdoc.InnerXml);
Console.ReadLine();
Console.WriteLine(new string('-', 80));

生成

<root>
    <EncryptedData Type="http://www.w3.org/2001/04/xmlenc#Element" xmlns="http://www.w3.org/2001/04/xmlenc#">
        <EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#aes256-cbc" />
        <KeyInfo xmlns="http://www.w3.org/2000/09/xmldsig#">
            <KeyName>helloworldkey</KeyName>
            <EncryptedKey Recipient="recipient1@foobar.com" xmlns="http://www.w3.org/2001/04/xmlenc#">
                <EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#rsa-1_5" />
                <KeyInfo xmlns="http://www.w3.org/2000/09/xmldsig#">
                    <KeyName>recipient1@foobar.com</KeyName>
                </KeyInfo>
                <CipherData>
                    <CipherValue>bmVT4SuAgWto6NJoTnUhrwaQ5/bWx39WKfs8y/QEQbaEBqdvl2Wa3woQGZxfigZ2wsWZQJFW0YGMII0W6AATnsqGOOVEbdGxmnvXRISiRdhcyNHkHot0kDK987y446ws5CZQQuz8inGq/SNrhiK6RyVnBE4ykWjrJyIS5wScwqA=</CipherValue>
                </CipherData>
                <CarriedKeyName>helloworldkey</CarriedKeyName>
            </EncryptedKey>
            <EncryptedKey Recipient="recipient2@foobar.com" xmlns="http://www.w3.org/2001/04/xmlenc#">
                <EncryptionMethod Algorithm="http://www.w3.org/2001/04/xmlenc#rsa-1_5" />
                <KeyInfo xmlns="http://www.w3.org/2000/09/xmldsig#">
                    <KeyName>recipient2@foobar.com</KeyName>
                </KeyInfo>
                <CipherData>
                    <CipherValue>oR8NPTm1NasWeDXBjayLk+p9/5RTWOZwNJHUMTQpZB9v1Aasi75oSjGqSqN0HMTiviw6NWz8AvHB9+i08L4Hw8JRDLxZgjaKqTGu31wXmM3Vc0CoYQ15AWMZN4q4tSxDhwuT8fp9SN+WFBm+M3w3bcPoooAazzDHK3ErzfXzYiU=</CipherValue>
                </CipherData>
                <CarriedKeyName>helloworldkey</CarriedKeyName>
            </EncryptedKey>
        </KeyInfo>
        <CipherData>
            <CipherValue>ohjWIEFf2WO6v/CC+ugd7uxEKGJlxgdT9N+t3MhoTIyXHqT5VlknWs0XlAhcgajkxKFjwVO3p413eRSMTLXKCg==</CipherValue>
        </CipherData>
    </EncryptedData>
</root>

要解密文档，必须提供密钥名称和证书私钥之间的映射：

// Decrypt
string myKeyName = "recipient1@foobar.com";
// specify we want to use the key for recipient1
var encryptedDoc = new EncryptedXml(xdoc);
encryptedDoc.AddKeyNameMapping(myKeyName, rsaKey1);
encryptedDoc.Recipient = myKeyName;
// Decrypt the element.
encryptedDoc.DecryptDocument();
// show the result
Console.Write(xdoc.InnerXml);
Console.ReadLine();

结果：

<root><encryptme>hello world</encryptme></root>
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