tweakable

adjective2

1. •
   That can be tweaked; moddable, customizable.

   • And it's every bit as tweakable as previous versions of Windows. You can turn off the new Aero look, or just selected parts of it. — 2007
2. •
   Of a block cipher: accepting a second input (the "tweak"), used in conjunction with the key to select the permutation computed by the cipher.