Hello Stackoverflow用户,我正在进行有关RSA加密和解密的工作,并且遇到了一个棘手的问题。
使用Visual Studio我创建了一个简单的表单,其中包含2个文本框(一个用于纯文本消息,另一个用于显示加密的消息)和4个按钮(2个清除按钮用于清除相应的文本框以及加密按钮和解密按钮)
public partial class Form1 : Form
{
//Strings to hold public & private keys
String publicKey, privateKey;
UnicodeEncoding encoder = new UnicodeEncoding();
public Form1()
{
RSACryptoServiceProvider myRSA = new RSACryptoServiceProvider();
InitializeComponent();
privateKey = myRSA.ToXmlString(true);
publicKey = myRSA.ToXmlString(false);
}
private void btnClr1_Click(object sender, EventArgs e)
{
txtPlain.Text = "";
txtPlain.Refresh();
}
private void btnClr2_Click(object sender, EventArgs e)
{
txtCypher.Text = "";
txtCypher.Refresh();
}
private void btnEncrypt_Click(object sender, EventArgs e)
{
var myRSA = new RSACryptoServiceProvider();
//Set cryptoserviceprovider with the proper key
myRSA.FromXmlString(publicKey);
//Encode the data to encrypt as a byte array
var dataToEncrypt = encoder.GetBytes(txtPlain.Text);
//Encrypt the byte array
var encryptedByteArray = myRSA.Encrypt(dataToEncrypt, false).ToArray();
var length = encryptedByteArray.Count();
var item = 0;
var sb = new StringBuilder();
//Change each byte in the encrypted byte array to text
foreach(var x in encryptedByteArray)
{
item++;
sb.Append(x);
if (item < length) sb.Append(",");
}
txtCypher.Text = sb.ToString();
}
private void btnDecrypt_Click(object sender, EventArgs e)
{
var myRSA = new RSACryptoServiceProvider();
//Split data into an array
var dataArray = txtCypher.Text.Split(new char[] { ',' });
//Convert chars to bytes
byte[] dataByte = new byte[dataArray.Length];
for(int i = 0; i < dataArray.Length; i++) dataByte[i] = Convert.ToByte(dataArray[i]);
//Decrypt the byte array
myRSA.FromXmlString(privateKey);
var decryptedBytes = myRSA.Decrypt(dataByte, false);
//place into cypher text box
txtPlain.Text = encoder.GetString(decryptedBytes);
}
}
我对加密和解密邮件没有任何问题(显然,只要它们不超过RSA密钥大小)。
所以我正在努力修改我的程序,以允许加密和解密任何大小的消息。
这是我提出的代码,允许加密任何大小(这似乎有效)
private void btnEncrypt_Click(object sender, EventArgs e)
{
var myRSA = new RSACryptoServiceProvider();
//Set cryptoserviceprovider with the proper key
myRSA.FromXmlString(publicKey);
//Encode the data to encrypt as a byte array
var dataToEncrypt = encoder.GetBytes(txtPlain.Text);
//store dataLength
int dataLength = dataToEncrypt.Length;
//Check if dataLength > 128
if (dataLength > 128)
{
//Divide dataLength by 128 to determine how many cycles will be needed
double numOfCycles = (dataLength / 117);
//round up to nearest whole number
cycles = (int)Math.Ceiling(numOfCycles);
//for however many cycles
for (int i = 0; i < cycles; i++)
{
var myByteArray = new byte[117];
for (int j = 0; j < 117; j++)
{
int currentByte = i * 117 + j;
myByteArray[j] = dataToEncrypt[currentByte];
}
var encryptedByteArray = myRSA.Encrypt(myByteArray, false).ToArray();
var length = encryptedByteArray.Count();
var item = 0;
//Change each byte in the encrypted byte array to text
foreach (var x in encryptedByteArray)
{
item++;
sb.Append(x);
if (item < length) sb.Append(",");
}
txtCypher.Text = sb.ToString();
}
}
else
{
var encryptedByteArray = myRSA.Encrypt(dataToEncrypt, false).ToArray();
var length = encryptedByteArray.Count();
var item = 0;
var sb = new StringBuilder();
//Change each byte in the encrypted byte array to text
foreach(var x in encryptedByteArray)
{
item++;
sb.Append(x);
if (item < length) sb.Append(",");
}
txtCypher.Text = sb.ToString();
}
}
这是我用来处理任何大小消息解密的代码(这是给我错误的)
private void btnDecrypt_Click(object sender, EventArgs e)
{
var myRSA = new RSACryptoServiceProvider();
//Split data into an array
var dataArray = txtCypher.Text.Split(new char[] { ',' });
int length = dataArray.Count();
float numOfCycles = (length / 117);
int cycles = (int)Math.Ceiling(numOfCycles);
for (int i = 0; i < cycles; i++)
{
byte[] dataByte = new byte[117];
for(int j = 0; j < 117; j++)
{
//Convert chars to bytes
dataByte[j] = Convert.ToByte(dataArray[ i * 117 + j ]);
}
//Decrypt the byte array
myRSA.FromXmlString(privateKey);
var decryptedBytes = myRSA.Decrypt(dataByte, false);
txtPlain.Text += encoder.GetString(decryptedBytes);
}
}
抛出的错误是:
`System.Security.Cryptography.CryptographicException' occurred in mscorlib.dll. Additional information: Bad Data.`
第133行:var decryptedBytes = myRSA.Decrypt(dataByte, false);
非常感谢任何帮助/建议!谢谢大家!
答案 0 :(得分:0)
正如Luke Park所说,尝试将RSA作为链式算法通常被认为是不好的做法。它的目的是进行安全的密钥交换&#34;,这意味着加密的内容被假定为#34;是对称加密信息。
然而,如果你决定走这条路;问题是RSA-Encrypt总是产生一个长度为密钥大小的输出。您的代码假定=>&gt;中的117个字节117个字节;而事实并非如此。
由于RSA-Decrypt希望您使用RSA-Encrypt准备数据,因此它会报告&#34;错误数据&#34;因为你还没有给它一个有效的数据报(有效数据报的长度等于密钥大小)。