Question

I am making an activation server and the client will have to send infos to the activation server which send back the encrypted license file. However, in order to decrypt that file.. the client need the key or password.

What would be the best place to to put key or password used for encryption ? or else even better what would be the best way to transfer that key or password ?

Thanks!

Answer 1

The client application has a server address which it will connect to, sending whatever information is needed (I assume here you are sending the client’s config file). It can also know in advance the public key of the server in the config file.

The server uses its private key to sign a hash of the configuration file (which includes its public key that it can verify since it’s being sent to the server). This signed digital hash is sent back to the client.

At startup, the hash is verified in two ways:

• That the signature is correct.
• That the hash corresponds to the config file.

I don’t have any VB.Net code available now, but all the C# code can be found in C#3.0 in a Nutshell examples online.

Example code in C# Available under section The RSA class and followings