Reverse usage of public/private RSA encryption keys for licensing?

charismatic_evangelist_at_yahoo.com
Date: 11/23/04 

Date: 22 Nov 2004 21:15:46 -0800

The way that RSACryptoServiceProvider works is that we encrypt with a
public key and decrypt with a private key. This architecture works
great for people sending messages to me. However, I now have the
opposite application:

I want to put a license file on a destination computer and be sure
that it remains unaltered. It would be great if I could encrypt it
with a private key at our office and transmit the public key and the
encrypted file to the destination computer, where anybody can decrypt
it and read it, but not change it because we have the private key at
our office.

I've read posts to "simply reverse the public and private RSA keys"
but tried several variations of switching RsaParameters.D, DP, P, DQ,
Modulus and others, to no avail.

I'm sure that a solution exists, just that I do not know it.

How do I, in C# .NET, send a license file to a destination computer,
with a public key, anybody can read it, but only we can change it?

Thanks.

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