A print substance cartridge for a printing device includes a supply of print substance for the printing device, a non-volatile memory, and logic. The memory stores authentication values by which the print substance cartridge is authenticated by the printing device, and/or a cryptographic key from which a plurality of authentication values are able to be generated within the print substance cartridge. The memory stores hash values corresponding to the authentication values and by which the authentication values are verifiable by the printing device. The logic is to, in response to a request from the printing device for one of the authentication values and including an identifier, provide the authentication value associated with the identifier to the printing device. The logic is to, in response to a request from the printing device for one or more hash values of the hash values, provide the requested one or more hash values.