A chip for a cartridge with dispensable material may be provided. In one aspect, the chip may comprise a non-volatile memory for storing a number tracking amount of dispensable material in the cartridge, a key storage for storing an encryption key, a signature verification module and circuit components. The circuit components may be configured to receive and process a first message, receive and validate a second message, and update the amount of dispensable material if the validation of the second message succeeds. The first message may comprise a first command and an operation input value for a print job at the cartridge, and to process the first message may comprise decreasing the amount of dispensable material. The second message may comprise a second command to increase the amount of dispensable material, and may be validated using the signature validation module and the encryption key.