请帮我用公钥解密RSA

Question

公钥:11234d300d06092a864886f70d010101050003818b0030818702818100a3dc132169d3a3f0a3df4f7014d7c741ff6da7322b82d70f3ecdce16fac6349c8dfc63b1061fa11f8285d9afe6aa4f7ce01f645c9e0db3361d9ff9f165d23591f1f5e57833df4dcbd6ce7582208e8021d41a534ff0b5a5ed90d2642c51532668e3c90696c26c43b52cd4ec733c57b2fa4ca9ba03b606153e0aac01f9d1c3e523123243
签名:
4b3ef029516193b7d969ac1840083635a3e0901b8cd526caa44c1a072f496d7f0d4bca3942c0d9030bede37c7809b835cec787eb39e18b7596a724fba9805b24714dfbb0f4a3fb430b32e075254a114d4c38a0ac52ef46a0ad33dec3fbfc15417402a1399e65e46996c0cf49fc7ffca9222f8cd693c8376b6f928828967bec42
请问如何恢复签名以前的内容:

Answer 1

我写的方法如下:
public string  RSADecrypt(string KEY, string m_strDecryptString )
{
try
{
byte[] PlainTextBArray;
byte[] DypherTextBArray;
string Result; System.Security.Cryptography.RSACryptoServiceProvider rsa=new RSACryptoServiceProvider();


RSAParameters PublicKey = new RSAParameters();
PublicKey.Exponent = new byte[]{1,0,1};
PublicKey.Modulus =Convert.FromBase64String(KEY);
rsa.ImportParameters(PublicKey);
PlainTextBArray =Convert.FromBase64String(m_strDecryptString);
DypherTextBArray=rsa.Decrypt(PlainTextBArray, false);
Result=(new UnicodeEncoding()).GetString(DypherTextBArray);
return Result;
}
catch(Exception ex)
{
Response.Write(ex.Message);
}
return "";
}
调用:
string key="11234d300d06092a864886f70d010101050003818b0030818702818100a3dc132169d3a3f0a3df4f7014d7c741ff6da7322b82d70f3ecdce16fac6349c8dfc63b1061fa11f8285d9afe6aa4f7ce01f645c9e0db3361d9ff9f165d23591f1f5e57833df4dcbd6ce7582208e8021d41a534ff0b5a5ed90d2642c51532668e3c90696c26c43b52cd4ec733c57b2fa4ca9ba03b606153e0aac01f9d1c3e523123243";
string data="4b3ef029516193b7d969ac1840083635a3e0901b8cd526caa44c1a072f496d7f0d4bca3942c0d9030bede37c7809b835cec787eb39e18b7596a724fba9805b24714dfbb0f4a3fb430b32e075254a114d4c38a0ac52ef46a0ad33dec3fbfc15417402a1399e65e46996c0cf49fc7ffca9222f8cd693c8376b6f928828967bec42";
RSADecrypt(key,data);
出现错误提示:"不正确的项"请大家帮忙分析一下.谢谢了

Answer 2

数字签名和加密不同, 它是用来验证消息未被篡改的. 是原消息经过单向散列函数处理之后的输出. 所以即使你有Public/Private Key，也不可能将它恢复到原来的消息。

Answer 3

//用公匙加密
private void button4_Click(object sender, System.EventArgs e)
{   
   
crypt=new RSACryptoServiceProvider();
UTF8Encoding enc=new UTF8Encoding();
bytes=enc.GetBytes(textBox1.Text);
crypt.FromXmlString(  readpublickey );
bytes = crypt.Encrypt( bytes,false );
string encryttext=enc.GetString(bytes);//encryptbyte);
richtext2.Text="\n"+encryttext+"\n";  
}
//用私钥解密
private void button5_Click(object sender, System.EventArgs e)
{
   
UTF8Encoding enc=new UTF8Encoding();
byte [] decryptbyte;
crypt.FromXmlString ( readprivatekey ) ;
decryptbyte = crypt.Decrypt( bytes,false );
string decrypttext=enc.GetString( decryptbyte );
richtext3.Text = "\n" + decrypttext + "\n" ;
  
}

Answer 4

楼主，应该是你用base64解码公钥出错了，那个并不是公钥编码就算你得到公钥恐怕也不行，我很奇怪微软的设计RSAParameters 无法读取der编码的RSA密钥对，竟然要传Modulus（需要der解码啊）loadxml的时候要一个xml格式的公钥，为什么不能load der格式呢！！！万恶的微软，难道必须用cryptoapi么？？？