Paul C. Van Oorschot

Bio: Paul C. Van Oorschot is an academic researcher from Nortel. The author has contributed to research in topics: Hash-based message authentication code & X.509. The author has an hindex of 3, co-authored 3 publications receiving 268 citations.

Method for efficient management of certificate revocation lists and update information

Abstract: A method which allows implementation of the revocation of public-key certificates facilitates engineering of certificate revocation lists (CRLs). It solves the practical problem of CRLs potentially growing to unmanageable lengths by allowing CRLs to be segmented, based on size considerations or priority considerations related to revocation reasons. The method is used to distribute CRL information to users of certificate-based public-key systems. It is also applied more generally to update any field in a certificate by reference to a secondary source of authenticated information.

Method of building fast MACS from hash functions

Abstract: Hash functions are important in modern cryptography. Main applications are their use in conjunction with digital signature schemes and message authentication. Hash functions, commonly known as message authentication codes (MACs), have received widespread use in practice for data integrity and data origin authentication. New and inventive ways of building fast MACs from hash functions involve keyed hash functions in which secret keys are used at certain locations of the compression process and the keys are also hashed.

Systems and methods providing interactions between multiple servers and an end use device

Abstract: Methods and systems are provided which convey access control information from a first server to a second server through an end user device, for example in a system in which these servers and devices are all connected to the Internet. The method starts after the first server receives a message from the end user device. The first server in response to this message from the end user device sends a response message to the end user device containing the access control information to be conveyed to the second server, optionally after performing authentication. The response message also contains an instruction for the end user device to post a second message to the second server containing the information. The information is preferably contained in a content portion of the message. A hidden form may be used in the response message to contain the information. Optionally, the end user may be presented with an option to post the second message or not. This may allow conformance with data privacy laws requiring end user consent of data transfer. The instruction to post to the second server may consist of active content within the response message's content portion. This can be used to cause an end user device to store a cookie in association with a number of servers in different domains thereby implementing a multiple domain single sign-on function.

System and method for electronic transmission, storage and retrieval of authenticated documents

Abstract: Certificate Status Service that is configurable, directed, and able to retrieve status from any approved Certification Authority (CA) is disclosed. The CSS may be used by a Trusted Custodial Utility (TCU) and comparable systems or applications whose roles are validating the right of an individual to perform a requisite action, the authenticity of submitted electronic information objects, and the status of authentication certificates used in digital signature verification and user authentication processes. The validity check on authentication certificates is performed by querying an issuing CA. Traditionally, to create a trusted Public Key Infrastructure (PKI) needed to validate certificates, complex relationships are formed by cross- certification among CAs or by use of PKI bridges. The PKI and CA interoperability problem is addressed from a different point of view, with a focus on establishing a trust environment suitable for the creation, execution, maintenance, transfer, retrieval and destruction of electronic original information objects that may also be transferable records (ownership may change hands). A TCU is concerned only with a known set of 'approved CAs' although they may support a multitude of business environments, and within that set of CAs, only with those certificates that are associated with TCU user accounts. Building PKI/CA trusted relationships is not required as the CSS achieves a trusted environment by querying only approved CAs and maintaining caches of valid certificates' status.

System and method for electronic transmission, storage, and retrieval of authenticated electronic original documents

Abstract: Digital signatures are not valid indefinitely but only during the validity periods of their authentication certificates, which themselves are not indefinite but typically expire in order to limit the chances for compromise of the digital signatures. This poses a problem for electronic information objects that are intended to have legal weight for periods longer than the remaining validity period of a signature. There are thus provided methods of handling stored electronic original objects that have been created by signing information objects by respective transfer agents, submitting signed information objects to a trusted custodial utility, validating the submitted signed information objects by at least testing the integrity of the contents of each signed information object and the validity of the signature of the respective transfer agent, and applying to each validated information object a date-time stamp and a digital signature and authentication certificate of the trusted custodial utility. One method includes re-validating an electronic original object by verifying the digital signature of the trusted custodial utility applied to the object and applying to the re-validated object a current date-time stamp and a digital signature and current authentication certificate of the trusted custodial utility. Another method includes the step of creating an object-inventory from at least one stored electronic original object, where the object-inventory includes an object identifier and a signature block for each object from which the object-inventory is created. A date-time stamp and a digital signature and authentication certificate of the trusted custodial utility is applied to the object-inventory. Other methods involve handling information objects that are transferable records according to specified business rules, which avoids problems that can arise if copies of the transferable records can be mistaken for originals.

Efficient Certificate Revocation

Abstract: We propose new systems for certificate revocation that are more economical and efficient than traditional ones. We also point out what we believe to be a structural problem in traditional public-key infrastructures, and various ways to solve it.

Computer network security system and method having unilateral enforceable security policy provision

Abstract: A computer network security system and method utilizes digitally signed and centrally assigned policy data, such as password length rules, that is unilaterally enforced at network nodes by node policy enforcement engines. The policy data may be variable on a per client or network node basis through a centralized authority, such as a certification authority. The computer network security system provides variable security policy rule data for distribution to at least one network node through a central security policy rule data distribution source, such as the certification authority. The central security policy rule data distribution source associates a digital signature to the variable security policy rule data to ensure the integrity of the policies in the system. Each network node uses a policy rule data engine and policy rule table to decode policy rule data and enforce the policy rules as selectively determined through the central authority.

Method and apparatus for authenticating an open system application to a portable IC device

Abstract: A secure communication channel between an open system and a portable IC device is established. An application running on the open system desiring access to the information on the portable IC device authenticates itself to the portable IC device, proving that it is trustworthy. Once such trustworthiness is proven, the portable IC device authenticates itself to the application. Once such two-way authentication has been completed, trusted communication between the open system and the portable IC device can proceed, and private information that is maintained on the portable IC device can be unlocked and made available to the application.