Hi All,

      Basically, I would like to encrypt the data/file at the client end and should be able to decrypt it at the server side. So that client/end user should not manipulate the auto generated file from the application(window). I've gone through some of the articles from the net and I have found three options to archieve this.

1) Symmetric
    Adv: Can encrypt and decrypt using key values.
    Disadv: If the end user decode the manage code then it is possible to identify the key values. Then they can also decrypt the file at their end.
2) Asymmetric
    Adv: Can encrypt and decrypt using the public and private certificates.
3) Hash algorithum
    Add and disadv more or less similar to (1).

So i prefer to go with point (2), i.e Asymmetric. If anyone has better solutions to archieve encryption and decryption of the file then please let me know.

Thanks & Regards,
Shiby Chacko

I am trying to work out a program that will implement asymmetric encryption using CryptoAPI (C/C++ language) using digital certificates. What I want to do is use the public key from the certificate(currently PFX) to encrypt data, while use the private key to decrypt.

I started by writing a program that uses API's like CryptAcquireContext,CPGetUserkey() etc to encrypt and decrypt. However, while decrypting, I am not getting back the same program that existed before encryption.

Then I am trying out a program to do the same by extracting key information from the certificate. However, I am seeing at forums that some marshalling of public keys needs to be done to use it. Similarly, I am not being able to extract the private key from the certificate (Windows PFX).

Can you please advise me what needs to be done to get this working. Also, if you can share your code, it would be of great help.