Abstract: A trusted time infrastructure system provides time stamps for electronic documents from a local source. The system comprises a trusted master clock, a trusted local clock, and a network operations center. The trusted master clock and network operations center are located within secure environments controlled by a trusted third party. The trusted local clock may be located in an insecure environment. The trusted master clock is certified to be synchronized with an accepted time standard, such as a national time server. The trusted local clock, which issues time stamps, is certified to be synchronized with the trusted master clock. Time stamps and certifications are signed by the issuing device using public key cryptography to enable subsequent authentication. The network operations center logs clock certifications and responds to requests for authentication of time stamps.

Abstract: An apparatus for generating a precision frequency includes a receiver that tracks a CDMA pilot signal and extracts frequency and phase information. This information is then used by a processor to control a precision oscillator. The precision oscillator generates a precise frequency based on the CDMA pilot signal. Time of day information is also extracted by the receiver and processor.

Abstract: Access to stored information by a user is controlled by comparing an actual geographic position and/or an actual date/time with a geographic region and/or a date/time interval within which access to the stored information is authorized. The actual geographic position where the stored information is located, and the actual date/time can be determined, for example, based on signals received at a receiver supplying reliable position and time information, such as a GPS receiver. Access to the stored information is authorized if the actual geographic position and/or date/time falls within the authorized geographic region and/or date/time interval. The position and date/time information supplied by the receiver may be cryptographically signed and encrypted.

Abstract: A quantum medium is excited by laser light from a first electromagnetic source and is also exposed to radiation from a second electromagnetic source such that the radiation field from this second source is non-uniform in a direction transverse to the direction of passage of laser light though the quantum medium. The laser light that has passed through the quantum medium is detected by two photo detectors at two different locations transverse to the passage of laser light, with the light detected by each photo detector having passed through a substantially different region of the quantum medium than the light detected by the other photo detector, and with the radiation field from the second electromagnetic source having different intensities in these two regions. The different radiation field intensities in these two regions produce at each photo detector different intensity levels of the laser light that varies with the frequency of the second source of electromagnetic radiation.