Difference between revisions of "Cryptography"

Revision as of 15:32, 26 July 2024

Full Title

General resource site for Cryptography, Greek for secret writing.

Context

• Cryptography literally means Secret Writing and was use by Caesar in his communications from the Gallic wars. Since then, it has become a category of mathematics dealing with methods that are easy to invoke and difficult to discover. Commercial Cryptography is involved in:

1. protecting data from disclosure (its original purpose) and
2. assuring the source or integrity of messages.

• Specific details are on the wiki pages Secret Key Cryptography and Public Key Cryptography.
• Often abbreviated as just crypto.

Problems

• Cryptography is hard math that deals with the solution of hard problems. It is not a topic that can be addressed by programmers looking for simple solutions with a limited time budget.
• As mathematicians and computer architects continue to explore solutions space the hard problems of cryptography are found to have simpler solutions. The continued success of the attempts to solve hard problems results in a continued effort to find new hard problems that can replace those that have been solved.
• The impact of this constant churn in the list of hard problems is a similar churn in the cryptographic algorithms that are accepted as computationally secure.

Solutions

• Most programmatic solutions are not sufficiently robust to fend off attacks by determined adversaries. Bugs and new attacks are a fact of life.
• Thus any solution that depends on cryptography for security must be designed to allow new algorithms to be swapped out as old ones are solved or bugs are discovered.

Machines

Caesar had a Cryptographic machine. It was a cylindrical rod that was used for character by character substitution. Machines got more sophisticated over time, the deign of the Enigma machine was emblematic of the top-of-the-line machine. It has a typewriter input and a light indicating the substitution character to send. This design had several weakness, many can from known plain text attacks. The design was patented in the US by Arthur Scherbius in 1929. From that time on the machine designs were themselves a closely guarded secret. Since the Second World War nearly all machines are just computer programs, some of which run in Hardware Protection of some form as a Trusted Execution Environment (TEE) either generally or specially as in a trusted platform module (TPM) or a hardware security module (HSM).

Resources

• Bill's crypto page has a broad list of crypto methods.
• The core proof is describe on the wiki page Indistinguishability Obfuscation.