EXCERPT

What is Cryptography?

An excerpt from Secret Key Cryptography by Frank Rubin

Unbreakable Ciphers

Types of Cryptography

  • Hidden message, for example the messenger could swallow the message, or hide it in his boot heel or saddle, or simply memorize it. It was common in ancient times to have a messenger memorize a message in a language he did not understand.
  • Secret method, for example the Caesar Cipher where each letter of the alphabet is replaced by the letter 3 places later. That is, A becomes D, B becomes E, C becomes F, and so forth.
  • Disguised message, where the message is made to look like something else such as a design in the messenger’s garments.
  • Invisible message, such as microdots, or invisible inks which become visible when heated or exposed to acid.
  • Misdirection, for example where the signature or the shape and color of the paper are the true message, and everything else is distraction or disinformation.

Symmetric vs Asymmetric Cryptography

Block Ciphers vs Stream Ciphers

Mechanical vs Digital

Why Choose Secret Key?

Why Build Your Own?

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