In some embodiments, the invention is a personal digital network ("PDN") including hardware (sometimes referred to as Ingress circuitry) configured to transcrypt encrypted content that enters the PDN. Typically, the transcryption (decryption followed by re-encryption) is performed in hardware within the Ingress circuitry and the re-encryption occurs before the decrypted content is accessible by hardware or software external to the Ingress circuitry. Typically, transcrypted content that leaves the Ingress circuitry remains in re-encrypted form within the PDN whenever it is transferred between integrated circuits or is otherwise easily accessible by software, until it is decrypted within hardware (sometimes referred to as Egress circuitry) for display or playback or output from the PDN. Typically, the PDN is implemented so that no secret in Ingress or Egress circuitry (for use or transfer by the Ingress or Egress circuitry) is accessible in unencrypted form to software or firmware within the PDN or to any entity external to the PDN. Other aspects of the invention are methods for protecting content in a PDN (e.g., an open computing system) and devices (e.g., multimedia graphics cards, set top boxes, or video processors) for use in a PDN.