Abstract: A system for authenticating digital files includes an electronic device having means for handling digital files. The electronic device has a unique, hard encoded, device identifier. The system further includes a security key for interacting with the electronic device, the security key having a unique, hard encoded, key identifier. The electronic device further includes means for verifying a predetermined key-to-device association of the key identifier to the device identifier, means for refusing access to the electronic device upon unsuccessful key-to-device association verification, and means for associating both the device identifier and the key identifier with at least one of the handled digital files.

Abstract: An antigen, a water-soluble protein, is isolated from group A (beta-hemolytic) streptococci by suspending the streptococci in an aqueous medium and subjecting the resulting mixture to disintegration by various means whereby the streptococci cells are disrupted. The supernatant contains the antigen, which can be purified by fractionation, particularly chromatographic adsorption.