Examples associated with printer authentication are described. One example print container includes a space for a supply of print material and an interface for delivering the print material to a printer to which the print container is connected. An authentication module provides an authentication signal to a decrypted module embedded in firmware of the printer. The decrypted firmware module is kept in an encrypted state until decrypted by a decryption module embedded in the firmware of the printer. The decrypted module is decrypted after the decryption module receives a decryption key after release of the printer.