diff options
Diffstat (limited to 'src/scalar.h')
| -rw-r--r-- | src/scalar.h | 57 |
1 files changed, 34 insertions, 23 deletions
diff --git a/src/scalar.h b/src/scalar.h index f5d09f8d47..b590ccd6dd 100644 --- a/src/scalar.h +++ b/src/scalar.h @@ -22,72 +22,83 @@ #endif /** Clear a scalar to prevent the leak of sensitive data. */ -static void secp256k1_scalar_clear(secp256k1_scalar_t *r); +static void secp256k1_scalar_clear(secp256k1_scalar *r); /** Access bits from a scalar. All requested bits must belong to the same 32-bit limb. */ -static unsigned int secp256k1_scalar_get_bits(const secp256k1_scalar_t *a, unsigned int offset, unsigned int count); +static unsigned int secp256k1_scalar_get_bits(const secp256k1_scalar *a, unsigned int offset, unsigned int count); /** Access bits from a scalar. Not constant time. */ -static unsigned int secp256k1_scalar_get_bits_var(const secp256k1_scalar_t *a, unsigned int offset, unsigned int count); +static unsigned int secp256k1_scalar_get_bits_var(const secp256k1_scalar *a, unsigned int offset, unsigned int count); /** Set a scalar from a big endian byte array. */ -static void secp256k1_scalar_set_b32(secp256k1_scalar_t *r, const unsigned char *bin, int *overflow); +static void secp256k1_scalar_set_b32(secp256k1_scalar *r, const unsigned char *bin, int *overflow); /** Set a scalar to an unsigned integer. */ -static void secp256k1_scalar_set_int(secp256k1_scalar_t *r, unsigned int v); +static void secp256k1_scalar_set_int(secp256k1_scalar *r, unsigned int v); /** Convert a scalar to a byte array. */ -static void secp256k1_scalar_get_b32(unsigned char *bin, const secp256k1_scalar_t* a); +static void secp256k1_scalar_get_b32(unsigned char *bin, const secp256k1_scalar* a); /** Add two scalars together (modulo the group order). Returns whether it overflowed. */ -static int secp256k1_scalar_add(secp256k1_scalar_t *r, const secp256k1_scalar_t *a, const secp256k1_scalar_t *b); +static int secp256k1_scalar_add(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b); -/** Add a power of two to a scalar. The result is not allowed to overflow. */ -static void secp256k1_scalar_add_bit(secp256k1_scalar_t *r, unsigned int bit); +/** Conditionally add a power of two to a scalar. The result is not allowed to overflow. */ +static void secp256k1_scalar_cadd_bit(secp256k1_scalar *r, unsigned int bit, int flag); /** Multiply two scalars (modulo the group order). */ -static void secp256k1_scalar_mul(secp256k1_scalar_t *r, const secp256k1_scalar_t *a, const secp256k1_scalar_t *b); +static void secp256k1_scalar_mul(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b); + +/** Shift a scalar right by some amount strictly between 0 and 16, returning + * the low bits that were shifted off */ +static int secp256k1_scalar_shr_int(secp256k1_scalar *r, int n); /** Compute the square of a scalar (modulo the group order). */ -static void secp256k1_scalar_sqr(secp256k1_scalar_t *r, const secp256k1_scalar_t *a); +static void secp256k1_scalar_sqr(secp256k1_scalar *r, const secp256k1_scalar *a); /** Compute the inverse of a scalar (modulo the group order). */ -static void secp256k1_scalar_inverse(secp256k1_scalar_t *r, const secp256k1_scalar_t *a); +static void secp256k1_scalar_inverse(secp256k1_scalar *r, const secp256k1_scalar *a); /** Compute the inverse of a scalar (modulo the group order), without constant-time guarantee. */ -static void secp256k1_scalar_inverse_var(secp256k1_scalar_t *r, const secp256k1_scalar_t *a); +static void secp256k1_scalar_inverse_var(secp256k1_scalar *r, const secp256k1_scalar *a); /** Compute the complement of a scalar (modulo the group order). */ -static void secp256k1_scalar_negate(secp256k1_scalar_t *r, const secp256k1_scalar_t *a); +static void secp256k1_scalar_negate(secp256k1_scalar *r, const secp256k1_scalar *a); /** Check whether a scalar equals zero. */ -static int secp256k1_scalar_is_zero(const secp256k1_scalar_t *a); +static int secp256k1_scalar_is_zero(const secp256k1_scalar *a); /** Check whether a scalar equals one. */ -static int secp256k1_scalar_is_one(const secp256k1_scalar_t *a); +static int secp256k1_scalar_is_one(const secp256k1_scalar *a); + +/** Check whether a scalar, considered as an nonnegative integer, is even. */ +static int secp256k1_scalar_is_even(const secp256k1_scalar *a); /** Check whether a scalar is higher than the group order divided by 2. */ -static int secp256k1_scalar_is_high(const secp256k1_scalar_t *a); +static int secp256k1_scalar_is_high(const secp256k1_scalar *a); + +/** Conditionally negate a number, in constant time. + * Returns -1 if the number was negated, 1 otherwise */ +static int secp256k1_scalar_cond_negate(secp256k1_scalar *a, int flag); #ifndef USE_NUM_NONE /** Convert a scalar to a number. */ -static void secp256k1_scalar_get_num(secp256k1_num_t *r, const secp256k1_scalar_t *a); +static void secp256k1_scalar_get_num(secp256k1_num *r, const secp256k1_scalar *a); /** Get the order of the group as a number. */ -static void secp256k1_scalar_order_get_num(secp256k1_num_t *r); +static void secp256k1_scalar_order_get_num(secp256k1_num *r); #endif /** Compare two scalars. */ -static int secp256k1_scalar_eq(const secp256k1_scalar_t *a, const secp256k1_scalar_t *b); +static int secp256k1_scalar_eq(const secp256k1_scalar *a, const secp256k1_scalar *b); #ifdef USE_ENDOMORPHISM /** Find r1 and r2 such that r1+r2*2^128 = a. */ -static void secp256k1_scalar_split_128(secp256k1_scalar_t *r1, secp256k1_scalar_t *r2, const secp256k1_scalar_t *a); +static void secp256k1_scalar_split_128(secp256k1_scalar *r1, secp256k1_scalar *r2, const secp256k1_scalar *a); /** Find r1 and r2 such that r1+r2*lambda = a, and r1 and r2 are maximum 128 bits long (see secp256k1_gej_mul_lambda). */ -static void secp256k1_scalar_split_lambda_var(secp256k1_scalar_t *r1, secp256k1_scalar_t *r2, const secp256k1_scalar_t *a); +static void secp256k1_scalar_split_lambda(secp256k1_scalar *r1, secp256k1_scalar *r2, const secp256k1_scalar *a); #endif /** Multiply a and b (without taking the modulus!), divide by 2**shift, and round to the nearest integer. Shift must be at least 256. */ -static void secp256k1_scalar_mul_shift_var(secp256k1_scalar_t *r, const secp256k1_scalar_t *a, const secp256k1_scalar_t *b, unsigned int shift); +static void secp256k1_scalar_mul_shift_var(secp256k1_scalar *r, const secp256k1_scalar *a, const secp256k1_scalar *b, unsigned int shift); #endif |