Abstract: A tracking system is provided that tracks user browsing activity while maintaining user privacy. It is determined whether a cookie is stored in local storage of a client device. If the cookie is not stored: a tracking identification (ID) is generated; the tracking ID, a cookie rotation timestamp, and a failed request counter in a generated cookie is stored; and the generated cookie is copied and attached to a transmitted event. If the cookie is stored: it is determined whether a time indicated by a stored cookie rotation timestamp is in the past; if the time is in the past, a flag requesting a new cookie value is set for a transmitted event; and if the time is not in the past, the stored cookie is copied and attached to a transmitted event.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for preserving code safety of application code that is received in a portable, instruction-set-neutral format. One aspect of the subject matter described in this specification can be embodied in methods that include the actions of receiving a portable code file that is implemented in an instruction-set-neutral and source code independent format; translating the portable code file into native object code for execution on a particular instruction set architecture; generating a native executable for the particular instruction set architecture using the native object code; and validation the native executable using a trusted validator prior to execution of the native executable.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for providing a translation service that generates native object code by translating an intermediate representation of application code in a portable code format. One aspect of the subject matter described in this specification can be embodied in methods that include the actions of receiving a translation service request for a native executable for a particular instruction set architecture from a requestor, where the translation service request includes data specifying portable code in an instruction-set neutral format; obtaining the portable code; translating the portable code into native object code for execution on the particular instruction set architecture; generating a native executable for the particular instruction set architecture; and returning the native executable to the requestor.

Abstract: Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for offline shared security key calculation. In one aspect, a method includes entering a first secure communication session with a remote device. A plurality of nonces are provided to the remote device during the first secure communication session. The first secure communication session is exited. A communication is received from the remote device after exiting the first communication session. The communication includes an indication of one of the plurality of nonces. A session key is generated using the indicated one of the plurality of nonces. A second secure communication session is entered with the remote device using the generated session key. Other embodiments of this aspect include corresponding systems, apparatus, and computer programs, configured to perform the actions of the methods, encoded on computer storage devices.

Abstract: A digital ticket is procured by a client ticket consumer upon, preferably, the Internet from and by staged interaction with a ticket provider server. The digital ticket becomes embodied in a tangible transportable data storage medium, normally a 2-D bar code printed on paper by the consumer, or on the consumer's flexible disk or smart card, containing Sign(s,I||hash(R))||R where (1) R is a number having its origin in the computer of the ticket consumer, which number R is appended to (2) a number Sign(s,I||hash(R)). This number Sign(s,I||hash(R)) was earlier computed in the computer of the ticket provider as a digital signature using signature key s of a number hash(R) combined with event information I, and was subsequently communicated across the communications network to the computer of the ticket consumer.

Abstract: A system includes a portable information device and a computing unit, and is architected to enable the portable information device to identify its type and properties to the computing unit. The portable information device has a processor and a memory. The memory stores a device class tag which is indicative of a type of the portable information device. When communication is established between the portable information device and the computing unit, the portable information device sends an initial message which includes a result of a mathematical operation involving the device class tag. The mathematical operation renders it computationally difficult or infeasible to deduce the device class tag from the result so that the device class tag is not exposed from the portable information device. The result might be a hash value of the device class tag which is derived using a hashing function, or data that has been signed using the device class tag as a private signing key.

Abstract: A computer-implemented pseudo random number generator includes an input device to assemble multiple classes of bits from multiple sources into an input bit string. The multiple classes of bits include an internal class of bits from at least one source internal to the random number generator, such as a static bit register which maintains the current state of the generator. The input device also gathers one or more external classes of bits from one or more sources external to the random number generator, such as a machine class of bits which relate to operating parameters of the computer and an application class of bits which relate to execution of an application running on the computer. The input device concatenates the three classes of bits into an arbitrary length input bit string. The random number generator also has a hash computing device which computes an m-bit hash value of the input bit string assembled by the input device.