# Re: EC Key Derivation Problem

Fabrice <fabrice.gautier@xxxxxxxxx> wrote:
Examples:
You have a set of systems with the same Private Key (a) inside. If
you want to encrypt something for any of the system you use the Public
Key (A). Now, each system has a different Serial Number ("k"). You
want to encrypt something for one system only so you encrypt with B.

You are looking for identity-based cryptography. Your solution is too
simple, I'm afraid. If the serial number is public, it suffers from
an insider attack. If the serial number isn't public, you could just
as well use two different public keys, so what's the point?

--
Kristian Gjøsteen
.

## Relevant Pages

• Re: RSACryptoServiceProvider decrypt with public key
... key/decrypt with the private key and encrypt with the private key/decrypt ... encrypt data and send it back to Alice. ... only she can decrypt Bob's data. ... see the public key and the encrypted data, but she could not decrypt Bob's ...
(microsoft.public.dotnet.security)
• Re: Copy protection for a .NET application
... is stored in a flash memory of the smartcard, ... Hawill you reveal a private key, that's known by just one party. ... > 2) Encrypt the secret and IV with the public key. ... > 4) HL decrypts the stringusing private RSA key stored in the lock. ...
(microsoft.public.dotnet.languages.csharp)
• Re: Copy protection for a .NET application
... is stored in a flash memory of the smartcard, ... Hawill you reveal a private key, that's known by just one party. ... > 2) Encrypt the secret and IV with the public key. ... > 4) HL decrypts the stringusing private RSA key stored in the lock. ...
(microsoft.public.dotnet.framework)
• Re: Copy protection for a .NET application
... is stored in a flash memory of the smartcard, ... Hawill you reveal a private key, that's known by just one party. ... > 2) Encrypt the secret and IV with the public key. ... > 4) HL decrypts the stringusing private RSA key stored in the lock. ...
(microsoft.public.dotnet.general)
• Re: Encrypted files do they work for backups?
... I'm going to test it out myself on my own test SBS Server. ... >>If I use the administrator account, and I encrypt it EFS on a External ... >>> format you need the private key to decrypt the files ... do you have the recovery agent Encrypting File ...
(microsoft.public.windows.server.sbs)