Aims and methods of cryptography
Encryption steps: simple substitution
Encryption steps: polygraphic substitution and coding
Encryption steps: linear substitution
Encryption steps: transposition
Polyalphabetic encryption: families of alphabets
Polyalphabetic encryption: keys
Composition of classes of methods
Open encryption key systems
Exhausting combinatorial complexity
Anatomy of language: patterns
Polyalphabetic case: probable words
Anatomy of language: frequencies
Alignment of accompanying alphabets