We want to use a licensing system for our new software, so we know that our customers are using the same amount of apps that they paid for. The general idea is to get their processor ID and HDD serial number and combine them to make our license string. I want to use RSA encryption, so we can use the public and private keys. Heres how we want it to work:

1. Send customer the installer package.

2. On the load event, generate the numbers.

3. FTP the text file to us.

4. Encrypt the data and store in SQL Server

5. Send them back an encrypted text file(with added information like an expiring date or something at the bottom) and use the key to decode it.

6. I want the keys to be static, so for example, the keyword "DOSTUFF" will decrypt information.

7. I don't want the customers to look at the text file and maybe recognize the RSA pattern and decrypt it, without having the key.

Ive looked at some sample code, but cant seem to find anything. If someone can provide some sample codez, I would be eternally grateful!

Thanks in advance!

The RSA implementation in .Net has some annoying implementations. Have you tried CryptoLicensing which is based on custom RSA implementation and does what you want ?

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