scalar.h File Reference

#include "num.h"

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Functions
static void	secp256k1_scalar_clear (secp256k1_scalar *r)
	Clear a scalar to prevent the leak of sensitive data. More...
static unsigned int	secp256k1_scalar_get_bits (const secp256k1_scalar *a, unsigned int offset, unsigned int count)
	Access bits from a scalar. More...
static unsigned int	secp256k1_scalar_get_bits_var (const secp256k1_scalar *a, unsigned int offset, unsigned int count)
	Access bits from a scalar. More...
static void	secp256k1_scalar_set_b32 (secp256k1_scalar *r, const unsigned char *bin, int *overflow)
	Set a scalar from a big endian byte array. More...
static void	secp256k1_scalar_set_int (secp256k1_scalar *r, unsigned int v)
	Set a scalar to an unsigned integer. More...
static void	secp256k1_scalar_get_b32 (unsigned char *bin, const secp256k1_scalar *a)
	Convert a scalar to a byte array. More...
static int	secp256k1_scalar_add (secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b)
	Add two scalars together (modulo the group order). More...
static void	secp256k1_scalar_cadd_bit (secp256k1_scalar *r, unsigned int bit, int flag)
	Conditionally add a power of two to a scalar. More...
static void	secp256k1_scalar_mul (secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b)
	Multiply two scalars (modulo the group order). More...
static int	secp256k1_scalar_shr_int (secp256k1_scalar *r, int n)
	Shift a scalar right by some amount strictly between 0 and 16, returning the low bits that were shifted off. More...
static void	secp256k1_scalar_sqr (secp256k1_scalar *r, const secp256k1_scalar *a)
	Compute the square of a scalar (modulo the group order). More...
static void	secp256k1_scalar_inverse (secp256k1_scalar *r, const secp256k1_scalar *a)
	Compute the inverse of a scalar (modulo the group order). More...
static void	secp256k1_scalar_inverse_var (secp256k1_scalar *r, const secp256k1_scalar *a)
	Compute the inverse of a scalar (modulo the group order), without constant-time guarantee. More...
static void	secp256k1_scalar_negate (secp256k1_scalar *r, const secp256k1_scalar *a)
	Compute the complement of a scalar (modulo the group order). More...
static int	secp256k1_scalar_is_zero (const secp256k1_scalar *a)
	Check whether a scalar equals zero. More...
static int	secp256k1_scalar_is_one (const secp256k1_scalar *a)
	Check whether a scalar equals one. More...
static int	secp256k1_scalar_is_even (const secp256k1_scalar *a)
	Check whether a scalar, considered as an nonnegative integer, is even. More...
static int	secp256k1_scalar_is_high (const secp256k1_scalar *a)
	Check whether a scalar is higher than the group order divided by 2. More...
static int	secp256k1_scalar_cond_negate (secp256k1_scalar *a, int flag)
	Conditionally negate a number, in constant time. More...
static void	secp256k1_scalar_get_num (secp256k1_num *r, const secp256k1_scalar *a)
	Convert a scalar to a number. More...
static void	secp256k1_scalar_order_get_num (secp256k1_num *r)
	Get the order of the group as a number. More...
static int	secp256k1_scalar_eq (const secp256k1_scalar *a, const secp256k1_scalar *b)
	Compare two scalars. More...
static void	secp256k1_scalar_mul_shift_var (secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b, unsigned int shift)
	Multiply a and b (without taking the modulus!), divide by 2**shift, and round to the nearest integer. More...

Function Documentation

secp256k1_scalar_add()

static int secp256k1_scalar_add ( secp256k1_scalar *  r, const secp256k1_scalar *  a, const secp256k1_scalar *  b  )

static

Add two scalars together (modulo the group order).

Returns whether it overflowed.

Referenced by bench_ecmult_wnaf(), bench_scalar_add(), bench_scalar_inverse(), bench_scalar_inverse_var(), bench_wnaf_const(), main(), run_ecmult_chain(), run_scalar_tests(), run_test(), scalar_test(), secp256k1_ecdsa_sig_sign(), secp256k1_eckey_privkey_tweak_add(), secp256k1_ecmult_gen(), test_constant_wnaf(), test_ec_combine(), test_ecdsa_sign_verify(), test_ecmult_multi(), test_exhaustive_verify(), test_fixed_wnaf(), and test_wnaf().

secp256k1_scalar_cadd_bit()

static void secp256k1_scalar_cadd_bit ( secp256k1_scalar *  r, unsigned int  bit, int  flag  )

static

Conditionally add a power of two to a scalar.

The result is not allowed to overflow.

Referenced by scalar_test(), secp256k1_wnaf_const(), test_constant_wnaf(), and test_fixed_wnaf().

secp256k1_scalar_clear()

static void secp256k1_scalar_clear ( secp256k1_scalar *  r )

static

Clear a scalar to prevent the leak of sensitive data.

Referenced by secp256k1_ec_privkey_tweak_add(), secp256k1_ec_privkey_tweak_mul(), secp256k1_ec_pubkey_create(), secp256k1_ec_seckey_verify(), secp256k1_ecdh(), secp256k1_ecdsa_sig_sign(), secp256k1_ecdsa_sign(), secp256k1_ecdsa_sign_recoverable(), secp256k1_ecmult_gen(), secp256k1_ecmult_gen_blind(), secp256k1_ecmult_gen_context_clear(), secp256k1_ecmult_pippenger_batch(), and test_ecmult_multi().

secp256k1_scalar_cond_negate()

static int secp256k1_scalar_cond_negate ( secp256k1_scalar *  a, int  flag  )

static

Conditionally negate a number, in constant time.

Returns -1 if the number was negated, 1 otherwise

Referenced by run_wnaf(), secp256k1_wnaf_const(), test_constant_wnaf_negate(), and test_ecmult_multi().

secp256k1_scalar_eq()

static int secp256k1_scalar_eq ( const secp256k1_scalar *  a, const secp256k1_scalar *  b  )

static

Compare two scalars.

Referenced by run_scalar_tests(), scalar_test(), secp256k1_ecdsa_sig_verify(), test_constant_wnaf(), test_constant_wnaf_negate(), test_ecdsa_edge_cases(), test_ecmult_gen_blind(), test_ecmult_gen_blind_reset(), test_exhaustive_verify(), test_fixed_wnaf(), and test_wnaf().

secp256k1_scalar_get_b32()

static void secp256k1_scalar_get_b32 ( unsigned char *  bin, const secp256k1_scalar *  a  )

static

Convert a scalar to a byte array.

Referenced by scalar_test(), secp256k1_ec_privkey_negate(), secp256k1_ec_privkey_tweak_add(), secp256k1_ec_privkey_tweak_mul(), secp256k1_ecdsa_recoverable_signature_save(), secp256k1_ecdsa_recoverable_signature_serialize_compact(), secp256k1_ecdsa_sig_recover(), secp256k1_ecdsa_sig_serialize(), secp256k1_ecdsa_sig_verify(), secp256k1_ecdsa_signature_save(), secp256k1_ecdsa_signature_serialize_compact(), secp256k1_ecmult_gen_blind(), secp256k1_nonce_function_smallint(), secp256k1_scalar_get_num(), secp256k1_scalar_inverse_var(), test_bad_scalar(), test_ecdh_generator_basepoint(), test_ecdsa_end_to_end(), test_ecdsa_recovery_end_to_end(), test_exhaustive_sign(), and test_exhaustive_verify().

secp256k1_scalar_get_bits()

static unsigned int secp256k1_scalar_get_bits ( const secp256k1_scalar *  a, unsigned int  offset, unsigned int  count  )

static

Access bits from a scalar.

All requested bits must belong to the same 32-bit limb.

Referenced by scalar_test(), secp256k1_ecmult_gen(), secp256k1_ecmult_wnaf(), and test_constant_wnaf_negate().

secp256k1_scalar_get_bits_var()

static unsigned int secp256k1_scalar_get_bits_var ( const secp256k1_scalar *  a, unsigned int  offset, unsigned int  count  )

static

Access bits from a scalar.

Not constant time.

Referenced by scalar_test(), secp256k1_ecmult_wnaf(), and secp256k1_wnaf_fixed().

secp256k1_scalar_get_num()

static void secp256k1_scalar_get_num ( secp256k1_num *  r, const secp256k1_scalar *  a  )

static

Convert a scalar to a number.

Referenced by bench_num_jacobi(), random_num_order(), random_num_order_test(), scalar_test(), test_num_add_sub(), test_num_jacobi(), and test_num_mod().

secp256k1_scalar_inverse()

static void secp256k1_scalar_inverse ( secp256k1_scalar *  r, const secp256k1_scalar *  a  )

static

Compute the inverse of a scalar (modulo the group order).

Referenced by bench_scalar_inverse(), run_scalar_tests(), scalar_test(), secp256k1_ecdsa_sig_sign(), and test_ecdsa_edge_cases().

secp256k1_scalar_inverse_var()

static void secp256k1_scalar_inverse_var ( secp256k1_scalar *  r, const secp256k1_scalar *  a  )

static

Compute the inverse of a scalar (modulo the group order), without constant-time guarantee.

Referenced by bench_scalar_inverse_var(), run_scalar_tests(), secp256k1_ecdsa_sig_recover(), secp256k1_ecdsa_sig_verify(), and test_ecdsa_edge_cases().

secp256k1_scalar_is_even()

static int secp256k1_scalar_is_even ( const secp256k1_scalar *  a )

static

Check whether a scalar, considered as an nonnegative integer, is even.

Referenced by secp256k1_wnaf_const(), secp256k1_wnaf_fixed(), and test_constant_wnaf_negate().

secp256k1_scalar_is_high()

static int secp256k1_scalar_is_high ( const secp256k1_scalar *  a )

static

Check whether a scalar is higher than the group order divided by 2.

Referenced by scalar_test(), secp256k1_ecdsa_sig_sign(), secp256k1_ecdsa_signature_normalize(), secp256k1_ecdsa_verify(), secp256k1_wnaf_const(), and test_exhaustive_verify().

secp256k1_scalar_is_one()

static int secp256k1_scalar_is_one ( const secp256k1_scalar *  a )

static

Check whether a scalar equals one.

Referenced by run_scalar_tests(), scalar_test(), secp256k1_scalar_inverse_var(), and secp256k1_wnaf_const().

secp256k1_scalar_is_zero()

static int secp256k1_scalar_is_zero ( const secp256k1_scalar *  a )

static

Check whether a scalar equals zero.

Referenced by random_scalar_order(), random_scalar_order_test(), run_scalar_tests(), run_wnaf(), scalar_test(), secp256k1_ec_pubkey_create(), secp256k1_ec_seckey_verify(), secp256k1_ecdh(), secp256k1_ecdsa_sig_recover(), secp256k1_ecdsa_sig_sign(), secp256k1_ecdsa_sig_verify(), secp256k1_ecdsa_sign(), secp256k1_ecdsa_sign_recoverable(), secp256k1_eckey_privkey_tweak_add(), secp256k1_eckey_privkey_tweak_mul(), secp256k1_eckey_pubkey_tweak_mul(), secp256k1_ecmult_gen_blind(), secp256k1_ecmult_pippenger_wnaf(), secp256k1_ecmult_strauss_wnaf(), secp256k1_wnaf_const(), and secp256k1_wnaf_fixed().

secp256k1_scalar_mul()

static void secp256k1_scalar_mul ( secp256k1_scalar *  r, const secp256k1_scalar *  a, const secp256k1_scalar *  b  )

static

Multiply two scalars (modulo the group order).

Referenced by bench_scalar_mul(), run_ecmult_chain(), run_scalar_tests(), run_test(), scalar_test(), secp256k1_ecdsa_sig_recover(), secp256k1_ecdsa_sig_sign(), secp256k1_ecdsa_sig_verify(), secp256k1_eckey_privkey_tweak_mul(), secp256k1_scalar_inverse_var(), test_constant_wnaf(), test_ecmult_multi(), test_exhaustive_verify(), test_fixed_wnaf(), test_num_jacobi(), and test_wnaf().

secp256k1_scalar_mul_shift_var()

static void secp256k1_scalar_mul_shift_var ( secp256k1_scalar *  r, const secp256k1_scalar *  a, const secp256k1_scalar *  b, unsigned int  shift  )

static

Multiply a and b (without taking the modulus!), divide by 2**shift, and round to the nearest integer.

Shift must be at least 256.

Referenced by scalar_test().

secp256k1_scalar_negate()

static void secp256k1_scalar_negate ( secp256k1_scalar *  r, const secp256k1_scalar *  a  )

static

Compute the complement of a scalar (modulo the group order).

Referenced by bench_scalar_negate(), ecmult_const_mult_zero_one(), run_scalar_tests(), run_test(), scalar_test(), secp256k1_ec_privkey_negate(), secp256k1_ecdsa_sig_recover(), secp256k1_ecdsa_sig_sign(), secp256k1_ecdsa_signature_normalize(), secp256k1_ecmult_gen_blind(), secp256k1_ecmult_wnaf(), secp256k1_wnaf_const(), test_constant_wnaf(), test_constant_wnaf_negate(), test_ecdsa_edge_cases(), test_ecdsa_end_to_end(), test_ecmult_constants(), test_ecmult_multi(), test_fixed_wnaf(), test_point_times_order(), and test_wnaf().

secp256k1_scalar_order_get_num()

static void secp256k1_scalar_order_get_num ( secp256k1_num *  r )

static

Get the order of the group as a number.

Referenced by bench_num_jacobi(), run_scalar_tests(), scalar_test(), and test_num_jacobi().

secp256k1_scalar_set_b32()

static void secp256k1_scalar_set_b32 ( secp256k1_scalar *  r, const unsigned char *  bin, int *  overflow  )

static

Set a scalar from a big endian byte array.

Referenced by bench_setup(), generate_scalar(), r_from_k(), random_scalar_order(), random_scalar_order_test(), run_scalar_tests(), secp256k1_der_parse_integer(), secp256k1_ec_privkey_negate(), secp256k1_ec_privkey_tweak_add(), secp256k1_ec_privkey_tweak_mul(), secp256k1_ec_pubkey_create(), secp256k1_ec_pubkey_tweak_add(), secp256k1_ec_pubkey_tweak_mul(), secp256k1_ec_seckey_verify(), secp256k1_ecdh(), secp256k1_ecdsa_recover(), secp256k1_ecdsa_recoverable_signature_load(), secp256k1_ecdsa_recoverable_signature_parse_compact(), secp256k1_ecdsa_sig_sign(), secp256k1_ecdsa_sig_verify(), secp256k1_ecdsa_sign(), secp256k1_ecdsa_sign_recoverable(), secp256k1_ecdsa_signature_load(), secp256k1_ecdsa_signature_parse_compact(), secp256k1_ecdsa_verify(), secp256k1_ecmult_gen_blind(), secp256k1_scalar_inverse_var(), and test_ecdsa_edge_cases().

secp256k1_scalar_set_int()

static void secp256k1_scalar_set_int ( secp256k1_scalar *  r, unsigned int  v  )

static

Set a scalar to an unsigned integer.

Referenced by main(), run_scalar_tests(), run_wnaf(), scalar_test(), secp256k1_der_parse_integer(), secp256k1_eckey_pubkey_tweak_add(), secp256k1_eckey_pubkey_tweak_mul(), secp256k1_ecmult_gen_blind(), secp256k1_ecmult_multi_simple_var(), secp256k1_ecmult_multi_var(), secp256k1_nonce_function_smallint(), test_constant_wnaf(), test_ecdsa_edge_cases(), test_ecdsa_sign_verify(), test_ecmult_constants(), test_ecmult_multi(), test_ecmult_multi_batching(), test_exhaustive_ecmult(), test_exhaustive_ecmult_multi(), test_exhaustive_sign(), test_exhaustive_verify(), test_fixed_wnaf(), test_fixed_wnaf_small(), test_num_add_sub(), test_num_jacobi(), test_num_mod(), and test_wnaf().

secp256k1_scalar_shr_int()

static int secp256k1_scalar_shr_int ( secp256k1_scalar *  r, int  n  )

static

Shift a scalar right by some amount strictly between 0 and 16, returning the low bits that were shifted off.

Referenced by scalar_test(), secp256k1_wnaf_const(), test_constant_wnaf(), and test_fixed_wnaf().

secp256k1_scalar_sqr()

static void secp256k1_scalar_sqr ( secp256k1_scalar *  r, const secp256k1_scalar *  a  )

static

Compute the square of a scalar (modulo the group order).

Referenced by bench_scalar_sqr(), run_scalar_tests(), scalar_test(), and test_num_jacobi().