- See 
Possum for main information
Technology/Laboratory/Software/Possum for the developed design scope of the Software
Technology/Laboratory/Hardware/Possum for the developed design scope of the Hardware
Brain/Study/Possum/Hardware for the ongoing project concept
 
CAcert.org Possum Project
Possum is a cross-competence Project for an Open Source Security Module. This is like a commercial HSM, but driven to CAcert's more open requirements.
The Possum Project can be the basis of Next Generation Open Source CAcert.org Security Module / Signing-Server, and part of the Next Generation Design of CAcert.org Open Source Software BirdShack as well.
 
Business Proposal
- Possum is not yet designed.  In order to design Possum, we could (hypothetically) 
Design it ourselves
Contract it to an expert group
Tag along with a group like Cryptech open security hardware group.
 
This concept is about exploring the the third option.
A Design Competition for Possum
- This could be run along the lines of the NIST/AES effort. An open-to-all call asking for a design for each module. Each module should be specified to a sufficient standard.
 - A time-line should be set with phases.  For example, following the lines of the AES effort: 
- 1. Announce
 - 2. Open presentation of all designs, X months later
 - 3. Comment and attack period
 - 4. Selection of finalists
 - 5. Presentation of finalists
 - 6. Comment and attack period
 - 7. Selection of winner
 - 8. Production of reference implementations
 
 - This fits the criteria of a peer-reviewed exercise, so it is most of the way to being academically viable. To further market it, budget for the team(s) travel and accomodation to present their proposals within a major related conference.
 - Funding could be found from a number of sources.
 
Requirements
- Possum needs to be: 
- - Buildable by small independent groups.
 - - Low-cost
 - - Relatively secure 
- - Protect the key data from extraction
 - - Protect the system from unauthorised requests
 
 - - Small verifiable software footprint
 - - Simple, trailing edge hardware footprint
 - - Single standardised protocol
 - - Open access 
- - All components buildable and usable without license issues
 - - Published design
 - - No patents
 
 
 
Components
There are these Major Tech Components:
Hardware Platform
- Hardware Interfaces
- Physical Protection Module
- -
 
Protocol
- Serial
Software
- Crypto, protocol driver, key store, application
Hardware
- - Hardware must be readily sourcable and low cost.
 - - Security not speed.
 - - It should have an application interface and a management interface,
 - - Small footprint: Low power, low heat, small size.
 Requirements for the Hardware are developed at Technology/Laboratory/Hardware/Possum.
Notes on the project-work for the hardware side are at Brain/Study/Possum/Hardware.
Protocol
- - Certificate operations
 - - Capable of layering over different packet networks.
 - - Simple layout
 - - Some Management requests
 - - Highly reliable
 - - Simple layout
 
See fuller requirements at Technology/Laboratory/Software/Possum.
Software
- - Capable of digital signing
 - - Keeps logs of all requests received and handled
 - - Protocol driver
 - - Management access
 
See fuller requirements at Technology/Laboratory/Software/Possum.
Misc
Other Applications
- Our Primary interest is CAcert's digital signing server, but this design can be turned to other things: 
- Digital cash server, e.g., Ricardo or Epointsystem.
- - Personal safe for private information
 - - MP3 server
 - Tahoe server or other file-sharing technology
 
References
- Peter Gutmann, "An Open-source Cryptographic Coprocessor," Usenix 2000.
- Peter Gutmann, "Hardware Encryption Modules," forthcoming book.
Feedbacks
- iang at c.o
 Inputs & Thoughts, below:
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