Techniques are disclosed relating to modifying packet data to be sent across a communication link and/or bus. Data may be modified in accordance with one or more data processing algorithms, and according to the capabilities of a destination device to receive such modified data. Lossless compression algorithms may be used on data in order to achieve a higher effective bandwidth over a particular bus or link. Encryption algorithms may be used, as well as data format conversion algorithms. One or more processing elements of a communication channel controller or other structure within a computing device may be used to modify packet data, which may be in PCI-Express format in some embodiments. A packet prefix or header may be used to store an indication of what algorithm(s) has been used to modify packet data so that a destination device can process packets accordingly.