这是我的第一篇文章，所以希望我没有错过任何重要的内容。我在C＃做一个项目，我需要使用公钥/私钥加密来加密消息，然后通过SSL连接发送它。
我根据文档选择使用RSACryptoService，这是用于加密数据的唯一非对称加密方案。问题是我遇到了很多问题。 （我想做对称加密，但这不是我老师要我做的事情，根据他的说法，确定块大小应该很容易，然后它应该为你完成所有的工作。）好吧，到目前为止没有运气，我尝试了一些不同的方法，但现在我又回到了基础并再次尝试，这是我目前的代码：
public string[] GenerateKeysToStrings(string uniqueIdentifier)
{
string[] keys;
using (var rsa = new RSACryptoServiceProvider(4096))
{
try
{
string privateKey = rsa.ToXmlString(true);
string publicKey = rsa.ToXmlString(false);
this.pki.StoreKey(publicKey, uniqueIdentifier);
keys = new string[2];
keys[0] = privateKey;
keys[1] = publicKey;
}
finally
{
//// Clear the RSA key container, deleting generated keys.
rsa.PersistKeyInCsp = false;
}
}
return keys;
}
正如您所看到的，我生成密钥并通过将公钥发送到存储它的简单类来模仿PKI，然后将私钥写入文件
（请注意，我还有另一种方法可以做同样的事情但是将它存储到一个数组中，只是因为我想在我得到No such key exceptions时测试和简化一些事情，有时当我按照例如，所以我想通过简单地将rsa.ToXmlString字符串存储为数组中的字符串来简化它，但没有运气。）
现在我有一个加密和解密方法如下：
public string Encrypt(string keyString, string message)
{
string encryptedMessage;
using (var rsa = new RSACryptoServiceProvider())
{
try
{
//// Load the key from the specified path
var encryptKey = new XmlDocument();
encryptKey.Load(@"C:\Test\PrivateKeyInfo.xml");
rsa.FromXmlString(encryptKey.OuterXml);
//// Conver the string message to a byte array for encryption
//// var encoder = new UTF8Encoding();
ASCIIEncoding byteConverter = new ASCIIEncoding();
byte[] dataToEncrypt = byteConverter.GetBytes(message);
byte[] encryptedData = rsa.Encrypt(dataToEncrypt, false);
//// Convert the byte array back to a string message
encryptedMessage = byteConverter.GetString(encryptedData);
}
finally
{
//// Clear the RSA key container, deleting generated keys.
rsa.PersistKeyInCsp = false;
}
}
return encryptedMessage;
}
解密：
public string Decrypt(string keyString, string message)
{
string decryptedText;
using (var rsa = new RSACryptoServiceProvider())
{
try
{
//// Loads the keyinfo into the rsa parameters from the keyfile
/*
var privateKey = new XmlDocument();
privateKey.Load(keyString);
*/
rsa.FromXmlString(keyString);
//// Convert the text from string to byte array for decryption
ASCIIEncoding byteConverter = new ASCIIEncoding();
var encryptedBytes = byteConverter.GetBytes(message);
//// Create an aux array to store all the encrypted bytes
byte[] decryptedBytes = rsa.Decrypt(encryptedBytes, false);
decryptedText = byteConverter.GetString(decryptedBytes);
}
finally
{
//// Clear the RSA key container, deleting generated keys.
rsa.PersistKeyInCsp = false;
}
}
return decryptedText;
}
我知道这是一面文字，但我希望你可以帮助我，因为我已经把头撞到了墙上这么久，现在这不好笑：）
问题是，如何使用RSA（或任何其他公钥/私钥加密）加密邮件
以下是测试客户端：
public static void Main(string[] args)
{
PublicKeyInfrastructure pki = new PublicKeyInfrastructure();
Cryptograph crypto = new Cryptograph();
string[] keys = crypto.GenerateKeysToStrings("simonlanghoff@gmail.com");
string plainText = "Hello play with me, please";
string publicKey = crypto.GetPublicKey("simonlanghoff@gmail.com");
string encryptedText = crypto.Encrypt(keys[0], plainText);
string decryptedText = crypto.Decrypt(keys[1], encryptedText);
}
正如我所提到的，字符串数组就在那里，因为我想从XML文档中消除错误的解析错误......
当我运行测试客户端时，如果我使用私钥加密和公钥解密，我得到一个“密钥不存在异常”，如果我这样做，反过来，我得到一个错误的数据异常
请帮帮我们，如果你知道任何好的指南，或者可以告诉我如何直接对字符串消息实施公钥/私钥加密，请帮帮我。
我感谢任何帮助。
答案 0 :(得分：5)
这不是RSA加密应该如何完成的。
RSA是关于数学的。您加密的是一个数字，因此它必须是有限长度并且与您正在使用的RSA密钥对长度相匹配。使用的填充（PKCS＃1或OAEP）会进一步限制长度。
如果要使用RSA加密大数据，则需要间接进行 - 即使用对称密钥加密大数据并使用RSA公钥加密此密钥。
您可以在我的blog上阅读有关实施此内容的信息。
答案 1 :(得分：1)
好的，我终于找到了解决我在原帖中所述问题的解决方案。这是我没有经过彻底测试的东西，或者是我从一个小小的试错过程中想到的东西。
这是我目前的代码：
public static string Encrypt(string dataToEncrypt, RSAParameters publicKeyInfo)
{
//// Our bytearray to hold all of our data after the encryption
byte[] encryptedBytes = new byte[0];
using (var RSA = new RSACryptoServiceProvider())
{
try
{
//Create a new instance of RSACryptoServiceProvider.
UTF8Encoding encoder = new UTF8Encoding();
byte[] encryptThis = encoder.GetBytes(dataToEncrypt);
//// Importing the public key
RSA.ImportParameters(publicKeyInfo);
int blockSize = (RSA.KeySize / 8) - 32;
//// buffer to write byte sequence of the given block_size
byte[] buffer = new byte[blockSize];
byte[] encryptedBuffer = new byte[blockSize];
//// Initializing our encryptedBytes array to a suitable size, depending on the size of data to be encrypted
encryptedBytes = new byte[encryptThis.Length + blockSize - (encryptThis.Length % blockSize) + 32];
for (int i = 0; i < encryptThis.Length; i += blockSize)
{
//// If there is extra info to be parsed, but not enough to fill out a complete bytearray, fit array for last bit of data
if (2 * i > encryptThis.Length && ((encryptThis.Length - i) % blockSize != 0))
{
buffer = new byte[encryptThis.Length - i];
blockSize = encryptThis.Length - i;
}
//// If the amount of bytes we need to decrypt isn't enough to fill out a block, only decrypt part of it
if (encryptThis.Length < blockSize)
{
buffer = new byte[encryptThis.Length];
blockSize = encryptThis.Length;
}
//// encrypt the specified size of data, then add to final array.
Buffer.BlockCopy(encryptThis, i, buffer, 0, blockSize);
encryptedBuffer = RSA.Encrypt(buffer, false);
encryptedBuffer.CopyTo(encryptedBytes, i);
}
}
catch (CryptographicException e)
{
Console.Write(e);
}
finally
{
//// Clear the RSA key container, deleting generated keys.
RSA.PersistKeyInCsp = false;
}
}
//// Convert the byteArray using Base64 and returns as an encrypted string
return Convert.ToBase64String(encryptedBytes);
}
/// <summary>
/// Decrypt this message using this key
/// </summary>
/// <param name="dataToDecrypt">
/// The data To decrypt.
/// </param>
/// <param name="privateKeyInfo">
/// The private Key Info.
/// </param>
/// <returns>
/// The decrypted data.
/// </returns>
public static string Decrypt(string dataToDecrypt, RSAParameters privateKeyInfo)
{
//// The bytearray to hold all of our data after decryption
byte[] decryptedBytes;
//Create a new instance of RSACryptoServiceProvider.
using (RSACryptoServiceProvider RSA = new RSACryptoServiceProvider())
{
try
{
byte[] bytesToDecrypt = Convert.FromBase64String(dataToDecrypt);
//// Import the private key info
RSA.ImportParameters(privateKeyInfo);
//// No need to subtract padding size when decrypting (OR do I?)
int blockSize = RSA.KeySize / 8;
//// buffer to write byte sequence of the given block_size
byte[] buffer = new byte[blockSize];
//// buffer containing decrypted information
byte[] decryptedBuffer = new byte[blockSize];
//// Initializes our array to make sure it can hold at least the amount needed to decrypt.
decryptedBytes = new byte[dataToDecrypt.Length];
for (int i = 0; i < bytesToDecrypt.Length; i += blockSize)
{
if (2 * i > bytesToDecrypt.Length && ((bytesToDecrypt.Length - i) % blockSize != 0))
{
buffer = new byte[bytesToDecrypt.Length - i];
blockSize = bytesToDecrypt.Length - i;
}
//// If the amount of bytes we need to decrypt isn't enough to fill out a block, only decrypt part of it
if (bytesToDecrypt.Length < blockSize)
{
buffer = new byte[bytesToDecrypt.Length];
blockSize = bytesToDecrypt.Length;
}
Buffer.BlockCopy(bytesToDecrypt, i, buffer, 0, blockSize);
decryptedBuffer = RSA.Decrypt(buffer, false);
decryptedBuffer.CopyTo(decryptedBytes, i);
}
}
finally
{
//// Clear the RSA key container, deleting generated keys.
RSA.PersistKeyInCsp = false;
}
}
//// We encode each byte with UTF8 and then write to a string while trimming off the extra empty data created by the overhead.
var encoder = new UTF8Encoding();
return encoder.GetString(decryptedBytes).TrimEnd(new[] { '\0' });
}
正如我所说的那样，除了尺寸之外，我还没有对它进行过大量的测试，但它似乎正在做它应该做的事情。我仍然是新手，所以我真的希望你仔细检查我的代码：）
答案 2 :(得分：0)
也许我错过了一些东西，但看起来你的Encrypt（）函数没有使用keyString参数或encryptKey的内容。