cryptopunk

Cryptopunk is a strategy hacking game set in a dystopian near future. Break into the servers of sinister corporations, steal their assets, and reveal their nefarious deeds to the world!

Assemble a suite of hacking tools for each mission, then control your programs in turn-based combat against the corporation's security programs to take control of the network and gain access to secret data. You'll need a combination of stealth and strategy to succeed.