User:Sandy Harris

 Where Sandy lives it is approximately: 19:58

I'm a baby-boomer Canadian currently teaching English and IT subjects in China. My academic qualifications are a BA in Psychology and a Certificate in Teaching English as a Second Language, both from Carleton U in Ottawa. I also did some work toward an M Phil in computational linguistics at U of Birmingham, UK, but did not complete that degree.

I am quite active on Wikitravel, where I'm an admin, and sometimes contribute to other wikis. See my Wikitravel user page: [1].

I've spent two substantial chunks of my career as a teacher — 1978-83 and 2002-date — mainly because that is a good way to support travel. At other times I've worked in computing, mostly as a technical writer but a bit of everything else too.

I wrote most of the documentation for the FreeS/WAN project, a Linux implementation of the IPsec encryption protocols. I have permission to re-use that text here User_talk:Sandy_Harris/Permission.

Citizendium articles where I was the main writer:

• Block cipher [r]: A symmetric cipher that operates on fixed-size blocks of plaintext, giving a block of ciphertext for each ^[e]
• Stream cipher [r]: A cipher that encrypts data by mixing it with the output of a pseudorandom number generator controlled by a key; to decrypt, run the same generator with the same key to get the same pseudorandom data, then reverse the mixing step. ^[e]
• Kerckhoffs' Principle [r]: The principle, formulated by Auguste Kerckhoffs, that security in a cipher should not depend on keeping the details of the cipher secret; it should depend only on keeping the key secret. ^[e]
• Brute force attack [r]: An attempt to break a cipher by trying all possible keys; long enough keys make this impractical. ^[e]
• Cypherpunk [r]: People interested in cryptography as a tool for privacy, anonymity and social change. ^[e]
• FreeSWAN [r]: A Linux implementation of the IPsec protocols, intended to make wholesale monitoring of the Internet impossible. ^[e]

Others I have contributed heavily to:

• Cryptography [r]: A field at the intersection of mathematics and computer science that is concerned with the security of information, typically the confidentiality, integrity and authenticity of some message. ^[e]
• Cryptanalysis [r]: The sub-field of cryptology which deals with breaking into existing codes and ciphers. ^[e]

I'm interested in computer security and cryptography. I think my latest papers ([2], [3]) on combining stream ciphers and block ciphers, are fairly interesting.

My Erdos number is five, via Carlisle Adams, Michael Weiner and Ron Rivest.