Efficient retrieval of cryptographic evidence

• US 7,818,575 B2
• Filed: 06/24/2005
• Issued: 10/19/2010
• Est. Priority Date: 06/24/2005
• Status: Expired due to Fees

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Hurst, Ryan M., Agarwal, Vishal, Cross, David B., Hallin, Philip J., Yiu, Kelvin S.
• Primary Examiner(s): Vu; Kimyen
• Assistant Examiner(s): King; John B
• Application Number:
  US11/166,884
• Publication Number:
  US 20060294576A1
• Time in Patent Office: 1,943 Days
• Field of Search: 726/1, 713/175
• US Class Current: 713/175
• CPC Class Codes: H04L 2209/76 Proxy, i.e. using intermediary entity to perform cryptographic operations network architectures or network communication protocols using hop-by-hop encryption H04L63/0464
• CPC Class Codes: H04L 2209/80 Wireless network architectures or network communication protocols for wireless network security H04W12/00
• CPC Class Codes: H04L 63/20 for managing network security; network security policies in general filtering policies H04L63/0227
• CPC Class Codes: H04L 9/3268 using certificate validation, registration, distribution or revocation, e.g. certificate revocation list [CRL]

Abstract

An efficient protocol for retrieving cryptographic evidence may be selected by evaluating a local policy and a number of relevant factors. Furthermore, updated cryptographic evidence may be prefetched during a time period in which there is a low volume of requests for cryptographic evidence. This low volume time period may be defined, approximately, as an overlapping window in which both a first cryptographic evidence publication and a second cryptographic evidence publication are valid.

Claims

1. A method for efficiently prefetching cryptographic evidence, the method comprising:

identifying by at least one computer processor a next update time at which a first cryptographic evidence publication ceases to be valid;

identifying a next publish time at which a second cryptographic evidence publication becomes valid; and

selecting by the at least one computer processor a prefetch time that is a time between the next publish time and the next update time, wherein the prefetch time is selected as a function of a random number, wherein selecting the prefetch time comprises;

calculating a first time by adding a delta time period to the next publish time;

calculating a second time by subtracting the delta time period from the next update time;

selecting a third time within an adjusted time period between the first time and the second time by;

calculating a proxy identifier based on caching information;

selecting the random number;

calculating a first part that is a modulus of half of the adjusted time period and the proxy identifier;

calculating a second part that is a modulus of half of the adjusted time period and the random number; and

setting the third time to be the sum of the next publish time, the delta time, the first part, and the second part; and

setting the prefetch time to be the third time; and

prefetching the cryptographic evidence at the prefetch time.

2. The method of claim 1, further comprising prefetching the cryptographic evidence according to a prefetch priority order corresponding to the frequency with which an issuer of the cryptographic evidence is checked.

3. A computer storage medium, excluding carrier waves, having computer executable instructions that, when executed by a computer, cause the computer to perform acts comprising:

identifying by at least one computer processor a next update time at which a first cryptographic evidence publication ceases to be valid;

identifying a next publish time at which a second cryptographic evidence publication becomes valid; and

selecting by the at least one computer processor a prefetch time that is a time between the next publish time and the next update time, wherein the prefetch time is selected as a function of a random number, wherein selecting the prefetch time comprises;

calculating a first time by adding a delta time period to the next publish time;

calculating a second time by subtracting the delta time period from the next update time;

selecting a third time within an adjusted time period between the first time and the second time by;

calculating a proxy identifier based on caching information;

selecting the random number;

calculating a first part that is a modulus of half of the adjusted time period and the proxy identifier;

calculating a second part that is a modulus of half of the adjusted time period and the random number; and

setting the third time to be the sum of the next publish time, the delta time, the first part, and the second part; and

setting the prefetch time to be the third time; and

prefetching the cryptographic evidence at the prefetch time.