Method and system for securing a printhead in a closed system metering device

A metering device comprising:

• an accounting device having a security device and an encryption device, said encryption device adapted to generate a first pseudo-random sequence and a second pseudo-random sequence, a portion less than all of said first pseudo-random sequence being utilized to encrypt communications being output from said accounting device, said portion of said first pseudo-random sequence being determined based on said second pseudo-random sequence;
• and
• a printing device coupled to said accounting device to receive said encrypted communications, said printing device having a decryption device adapted to generate said first pseudo-random sequence and said second pseudo-random sequence, said decryption device utilizing a portion less than all of said first pseudo-random sequence generated by said decryption device to decrypt said encrypted communications received from said accounting device, said portion of said first pseudo-random sequence used to decrypt said encrypted communications being determined based on said second pseudo-random sequence generated by said decryption device.

A printing device comprising:

• an input port to receive communications, said communications being encrypted based on a portion of a first pseudo-random sequence, said portion of said first pseudo-random sequence being less than all of said first pseudo-random sequence and being determined based on a second pseudo-random sequence;
• and
• a decryption device coupled to said input port, said decryption device adapted to generate said first pseudo-random sequence and said second pseudo-random sequence, said decryption device utilizing a portion less than all of said generated first pseudo-random sequence to decrypt said encrypted communications, said portion of said generated first pseudo-random sequence utilized to decrypt said encrypted communications being determined based on said generated second pseudo-random sequence.