ngram.h File Reference

#include "crack.h"

Go to the source code of this file.

Macros
#define	ENIGMA_BIIDX(a, b)   ((a << 5) | b)
	Generate a bigram index from two characters (for array lookup)
#define	ENIGMA_TRIIDX(a, b, c)   ((a << 10) | (b << 5) | c)
	Generate a trigram index from three characters (for array lookup)
#define	ENIGMA_QUADIDX(a, b, c, d)   ((a << 15) | (b << 10) | (c << 5) | d)
	Generate a quadgram index from four characters (for array lookup)

Functions
float	enigma_bigram_score (const EnigmaCrackParams *, const char *)
	Score text using bigram frequencies.
float	enigma_trigram_score (const EnigmaCrackParams *, const char *)
	Score text using trigram frequencies.
float	enigma_quadgram_score (const EnigmaCrackParams *, const char *)
	Score text using quadgram frequencies.

Detailed Description

This file declares functions for cracking Enigma configurations using n-gram scoring.

Macro Definition Documentation

ENIGMA_BIIDX

#define ENIGMA_BIIDX	(		a,
			b
	)		((a << 5) | b)

Generate a bigram index from two characters (for array lookup)

ENIGMA_QUADIDX

#define ENIGMA_QUADIDX	(		a,
			b,
			c,
			d
	)		((a << 15) | (b << 10) | (c << 5) | d)

Generate a quadgram index from four characters (for array lookup)

ENIGMA_TRIIDX

#define ENIGMA_TRIIDX	(		a,
			b,
			c
	)		((a << 10) | (b << 5) | c)

Generate a trigram index from three characters (for array lookup)

Function Documentation

enigma_bigram_score()

float enigma_bigram_score	(	const EnigmaCrackParams *	cfg,
		const char *	text
	)

Score text using bigram frequencies.

Parameters

cfg	Pointer to the cracking configuration structure.
text	The text to score.

Returns

The total bigram score.

enigma_quadgram_score()

float enigma_quadgram_score	(	const EnigmaCrackParams *	cfg,
		const char *	text
	)

Score text using quadgram frequencies.

Parameters

cfg	Pointer to the cracking configuration structure.
text	The text to score.

Returns

The total quadgram score.

enigma_trigram_score()

float enigma_trigram_score	(	const EnigmaCrackParams *	cfg,
		const char *	text
	)

Score text using trigram frequencies.

Parameters

cfg	Pointer to the cracking configuration structure.
text	The text to score.

Returns

The total trigram score.