Abstract: A word-oriented technique for generating a pseudo-random sequence, e.g., a keystream (17) for use in a stream cipher. Specifically, the technique utilizes two different arrays (653, 657) with each array having illustratively 256 32-bit elements. One array (653) contains a 256 element 32-bit S-box. An output stream generated by the S-box, i.e., St, is applied as one input to a first hash function. This hash function, in response to input St multiplied by a variable, C, provides the output keystream. S-box element St is then updated through a second hash function having, as its input, the current value of St multiplied by the variable C. The variable, C, initially a random variable, is itself updated, for use during a next iteration, through an additive combination, of its current value and a corresponding element in the second array (G), i.e., Gt. Both the S-box and G array can be initialized by, e.g., entirely filling each of these arrays with random 32-bit values.

Abstract: A word-oriented technique for generating a pseudo-random sequence, e.g., a keystream (17) for use in a stream cipher. Specifically, the technique utilizes two different arrays (653, 657) with each array having illustratively 256 32-bit elements. One array (653) contains a 256 element 32-bit S-box. An output stream generated by the S-box, i.e., St, is applied as one input to a first hash function. This hash function, in response to input St multiplied by a variable, C, provides the output keystream. S-box element St is then updated through a second hash function having, as its input, the current value of St multiplied by the variable C. The variable, C, initially a random variable, is itself updated, for use during a next iteration, through an additive combination, of its current value and a corresponding element in the second array (G), i.e., Gt. Both the S-box and G array can be initialized by, e.g., entirely filling each of these arrays with random 32-bit values.

Abstract: A technique for generating, for a given message to be signed, an authentic cryptographic signature that can be authenticated, by a recipient of the signed message, as having originated from a signor of the message; and appropriately authenticating such a signature. Specifically, this technique, given a message, such as, e.g., a numerical product copy identifier (83, 93), forms an authentic signature (87, 97), based on public-key cryptosystem, through use of generator value selected from points on an elliptic curve over a finite field. The authentic signature is generated using the generator value in conjunction with three keys; namely, a public key, a private key and a secret key, and thus substantially increases the security associated with cryptographic signatures generated through a conventional two-key public key cryptosystem. A unique product copy indicia can be formed by concatenating the identifier, for a given product copy, with its corresponding authentic signature.

Abstract: A technique for generating, for a given message to be signed, an authentic cryptographic signature that can be authenticated, by a recipient of the signed message, as having originated from a signor of the message; and appropriately authenticating such a signature. Specifically, this technique, given a message, such as, e.g., a numerical product copy identifier (83, 93), forms an authentic signature (87, 97), based on public-key cryptosystem, through use of generator value selected from points on an elliptic curve over a finite field. The authentic signature is generated using the generator value in conjunction with three keys; namely, a public key, a private key and a secret key, and thus substantially increases the security associated with cryptographic signatures generated through a conventional two-key public-key cryptosystem. A unique product copy indicia can be formed by concatenating the identifier, for a given product copy, with its corresponding authentic signature.