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| title | aliases | tags | ||
|---|---|---|---|---|
| 05-crypography |
|
news
- zodiac killer code cracked
- twitter leak
Brief history
- study of secret messages
- confidentiality of cia-triad
- also small role in integrity (authentication of message, and sender)
- history of cyprtopgraphy is interwined with information technology
Language use for communication seems to be part of human nature: perhaps the use of covert lanuage is too
need for confidentiality
"nothing to hide: nothing to fear" look at edward snowdens corrolary
We all have legit needs for privacy. Cryptography provides technical measure for ensuring this privacy.
history
- caesar cipher
- simple substitution scheme (rotation)
- vulnerable to cryptanalysis
General process
- encrypt
- plaintext + key => ciphertext
- key is a secret
- decrypt
- ciphertext + key => plaintext
mathmatically
- c = e(p, k)
- p = d(c, k)
Terminology
- copy later
Plaintext
refers to unencypted message. In the digital age the messages are often not plain text (ascii, unicode, etc).
digital crypto schemes normally work on the binary data (images, .docs, .txt, mp4 etc.)