Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people, just like you, are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
Solved

Decryption error

Posted on 2006-11-14
3
1,020 Views
Last Modified: 2008-02-01
I am trying to decrypt a string encrypted in Java.  My decryption code is below, but it generates a CryptographicException "The object cannot be found" on the line:
    X509Certificate2 myCertificate = new X509Certificate2(@"c:\signon_keystore.p12", password);
What am I doing wrong to decrypt this?


        static void Start(string[] args)
        {
            StreamReader sr = new StreamReader(File.OpenRead(@"c:\Source.txt"));
            string source = sr.ReadToEnd();
            string data = Regex.Match(source, "(?<=user=)([^&]*)").Value;
            string signData = Regex.Match(source, "(?<=authSignature=)(.*$)", RegexOptions.Multiline).Value;
            bool isTrue = VerifyData(HttpUtility.UrlDecode(data), HttpUtility.UrlDecode(signData));
            MessageBox.Show(isTrue.ToString());
        }

        static bool VerifyData(string data, string signature)
        {
            string password = "123456";
            X509Certificate2 myCertificate = new X509Certificate2(@"c:\signon_keystore.p12", password);
            RSACryptoServiceProvider provider1 = (RSACryptoServiceProvider)myCertificate.PublicKey.Key;
            byte[] sb = Convert.FromBase64String(signature);
            byte[] db = (new ASCIIEncoding()).GetBytes(data);
            return provider1.VerifyData(db, new SHA1CryptoServiceProvider(), sb);
        }
0
Comment
Question by:SkipFire
  • 2
3 Comments
 
LVL 13

Accepted Solution

by:
joechina earned 500 total points
ID: 17940409
Your key file might have problem.
Where do you get the key file?
0
 
LVL 4

Author Comment

by:SkipFire
ID: 17940464
I got the key file from our java team.  They are using it to encrypt, and I have been told that another java app is decrypting with it.  Unfortunately I have trouble getting any sort of information from our java team.
0
 
LVL 13

Expert Comment

by:joechina
ID: 17940538
Are you sure this is a PKCS12 key file?
Ok, Try this,

Under your XP, double click this file, and you should get a certificate import wizard.
If you can successfully import the key, then open IE , go to "internet option" -> "content" -> "certificate"
find the certificate you just imported. (hopefully, it's in your personal store)

then export the without private key. to DER format. Save it to a file called 'xxxx.cer'

Then try modify your code to
X509Certificate2 myCertificate = new X509Certificate2(@"xxxx.cer");

Good Luck
0

Featured Post

Free Tool: Port Scanner

Check which ports are open to the outside world. Helps make sure that your firewall rules are working as intended.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

This article introduced a TextBox that supports transparent background.   Introduction TextBox is the most widely used control component in GUI design. Most GUI controls do not support transparent background and more or less do not have the…
We all know that functional code is the leg that any good program stands on when it comes right down to it, however, if your program lacks a good user interface your product may not have the appeal needed to keep your customers happy. This issue can…
Two types of users will appreciate AOMEI Backupper Pro: 1 - Those with PCIe drives (and haven't found cloning software that works on them). 2 - Those who want a fast clone of their boot drive (no re-boots needed) and it can clone your drive wh…

856 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question