ENTROPY: randomness metrics for byte samples

Functions
double	n_entropy_chi_square (const unsigned char *data, size_t len)
	Chi-square statistic of the byte histogram against a uniform distribution over 256 values.
double	n_entropy_monobit (const unsigned char *data, size_t len)
	Fraction of set bits in the sample (0.0 .
double	n_entropy_shannon (const unsigned char *data, size_t len)
	Shannon entropy of the byte sample, in bits per byte (0.0 .

Detailed Description

Function Documentation

n_entropy_chi_square()

double n_entropy_chi_square	(	const unsigned char *	data,
		size_t	len
	)

Chi-square statistic of the byte histogram against a uniform distribution over 256 values.

Near 255 (the degrees of freedom) for random data; large for skewed data. Returns 0.0 for an empty/NULL sample.

Definition at line 64 of file n_entropy.c.

Referenced by main().

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n_entropy_monobit()

double n_entropy_monobit	(	const unsigned char *	data,
		size_t	len
	)

Fraction of set bits in the sample (0.0 .

. 1.0); 0.5 is the ideal for random data (the FIPS monobit idea). Returns 0.0 for an empty/NULL sample.

Definition at line 48 of file n_entropy.c.

Referenced by main().

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n_entropy_shannon()

double n_entropy_shannon	(	const unsigned char *	data,
		size_t	len
	)

Shannon entropy of the byte sample, in bits per byte (0.0 .

. 8.0). 0 means a single repeated value; 8 means a perfectly uniform byte histogram. Returns 0.0 for an empty/NULL sample.

Definition at line 29 of file n_entropy.c.

Referenced by main().

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