cx_mldsa_rounding.h File Reference

#include "cx_mldsa_poly.h"
#include "lcx_mldsa.h"

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Functions
int32_t	MLDSA_ROUNDING_power2round (int32_t a, int32_t *a0)
	For coefficient a, compute high and low bits a0, a1 such that a mod q = a1*2^D + a0, with -2^{D-1} < a0 <= 2^{D-1}.
int32_t	MLDSA_ROUNDING_decompose (int32_t a, int32_t *a0, int32_t gamma2)
	For coefficient a, compute high and low bits a0, a1 such that a mod q = a1*ALPHA + a0, where ALPHA = 2*gamma2.
uint32_t	MLDSA_ROUNDING_make_hint (int32_t a0, int32_t a1, int32_t gamma2)
	Compute hint bit. Returns 1 if adding ct0 to w - ct0 would change the high bits (i.e., the verifier must correct them).
int32_t	MLDSA_ROUNDING_use_hint (int32_t a, uint32_t hint, int32_t gamma2)
	Correct high bits using hint.
void	MLDSA_ROUNDING_poly_power2round (mldsa_poly *a1, mldsa_poly *a0, const mldsa_poly *a)
	Applies power2round to all coefficients of a polynomial.
void	MLDSA_ROUNDING_poly_decompose (mldsa_poly *a1, mldsa_poly *a0, const mldsa_poly *a, int32_t gamma2)
	Applies decompose to all coefficients of a polynomial.
void	MLDSA_ROUNDING_poly_use_hint (mldsa_poly *b, const mldsa_poly *a, const mldsa_poly *h, int32_t gamma2)
	Applies use_hint to all coefficients of a polynomial.

Function Documentation

MLDSA_ROUNDING_decompose()

int32_t MLDSA_ROUNDING_decompose	(	int32_t	a,
		int32_t *	a0,
		int32_t	gamma2
	)

For coefficient a, compute high and low bits a0, a1 such that a mod q = a1*ALPHA + a0, where ALPHA = 2*gamma2.

Parameters

[in]	a	Coefficient (standard representative).
[out]	a0	Low bits output.
[in]	gamma2	Low-order rounding range.

Returns

High bits a1.

Definition at line 31 of file cx_mldsa_rounding.c.

MLDSA_ROUNDING_make_hint()

uint32_t MLDSA_ROUNDING_make_hint	(	int32_t	a0,
		int32_t	a1,
		int32_t	gamma2
	)

Compute hint bit. Returns 1 if adding ct0 to w - ct0 would change the high bits (i.e., the verifier must correct them).

Parameters

[in]	a0	Low part.
[in]	a1	High part.
[in]	gamma2	Low-order rounding range.

Returns

Hint bit (0 or 1).

Definition at line 51 of file cx_mldsa_rounding.c.

MLDSA_ROUNDING_poly_decompose()

void MLDSA_ROUNDING_poly_decompose	(	mldsa_poly *	a1,
		mldsa_poly *	a0,
		const mldsa_poly *	a,
		int32_t	gamma2
	)

Applies decompose to all coefficients of a polynomial.

Parameters

[out]	a1	High bits output polynomial.
[out]	a0	Low bits output polynomial.
[in]	a	Input polynomial.
[in]	gamma2	Low-order rounding range.

Definition at line 94 of file cx_mldsa_rounding.c.

MLDSA_ROUNDING_poly_power2round()

void MLDSA_ROUNDING_poly_power2round	(	mldsa_poly *	a1,
		mldsa_poly *	a0,
		const mldsa_poly *	a
	)

Applies power2round to all coefficients of a polynomial.

Parameters

[out]	a1	High bits output polynomial.
[out]	a0	Low bits output polynomial.
[in]	a	Input polynomial.

Definition at line 87 of file cx_mldsa_rounding.c.

MLDSA_ROUNDING_poly_use_hint()

void MLDSA_ROUNDING_poly_use_hint	(	mldsa_poly *	b,
		const mldsa_poly *	a,
		const mldsa_poly *	h,
		int32_t	gamma2
	)

Applies use_hint to all coefficients of a polynomial.

Parameters

[out]	b	Output polynomial.
[in]	a	Input polynomial.
[in]	h	Hint polynomial.
[in]	gamma2	Low-order rounding range.

Definition at line 104 of file cx_mldsa_rounding.c.

MLDSA_ROUNDING_power2round()

int32_t MLDSA_ROUNDING_power2round	(	int32_t	a,
		int32_t *	a0
	)

For coefficient a, compute high and low bits a0, a1 such that a mod q = a1*2^D + a0, with -2^{D-1} < a0 <= 2^{D-1}.

Parameters

[in]	a	Coefficient.
[out]	a0	Low bits output.

Returns

High bits a1.

Definition at line 23 of file cx_mldsa_rounding.c.

MLDSA_ROUNDING_use_hint()

int32_t MLDSA_ROUNDING_use_hint	(	int32_t	a,
		uint32_t	hint,
		int32_t	gamma2
	)

Correct high bits using hint.

Parameters

[in]	a	Coefficient.
[in]	hint	Hint bit (0 or 1).
[in]	gamma2	Low-order rounding range.

Returns

Corrected high bits.

Definition at line 59 of file cx_mldsa_rounding.c.