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author | Pieter Wuille <pieter.wuille@gmail.com> | 2014-12-04 19:17:07 +0100 |
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committer | Pieter Wuille <pieter.wuille@gmail.com> | 2014-12-04 19:17:07 +0100 |
commit | 87bddb7a3a83aaad96b5b54b4bac34d8a71b3810 (patch) | |
tree | 8aab2e424df56d5786947d0827e98fe840a8caa6 /src/scalar.h | |
parent | d48555b36ac512161b81f9b6bca7bea16a0cd806 (diff) | |
download | bitcoin-87bddb7a3a83aaad96b5b54b4bac34d8a71b3810.tar.xz |
Squashed 'src/secp256k1/' changes from ad2028f..b0210a9
b0210a9 Merge pull request #135
ee3eb4b Fix a memory leak and add a number of small tests.
4d879a3 Merge pull request #134
d5e8362 Merge pull request #127
7b92cf6 Merge pull request #132
0bf70a5 Merge pull request #133
29ae131 Make scalar_add_bit test's overflow detection exact
9048def Avoid undefined shift behaviour
efb7d4b Use constant-time conditional moves instead of byte slicing
d220062 Merge pull request #131
82f9254 Fix typo
601ca04 Merge pull request #129
35399e0 Bugfix: b is restricted, not r
c35ff1e Convert lambda splitter to pure scalar code.
cc604e9 Avoid division when decomposing scalars
ff8746d Add secp256k1_scalar_mul_shift_var
bd313f7 Merge pull request #119
276f987 Merge pull request #124
25d125e Merge pull request #126
24b3c65 Add a test case for ECDSA recomputing infinity
32600e5 Add a test for r >= order signature handling
4d4eeea Make secp256k1_fe_mul_inner use the r != property
be82e92 Require that r and b are different for field multiplication.
597128d Make num optional
659b554 Make constant initializers independent from num
0af5b47 Merge pull request #120
e2e8a36 Merge pull request #117
c76be9e Remove unused num functions
4285a98 Move lambda-splitting code to scalar.
f24041d Switch all EC/ECDSA logic from num to scalar
6794be6 Add scalar splitting functions
d1502eb Add secp256k1_scalar_inverse_var which delegates to GMP
b5c9ee7 Make test_point_times_order test meaningful again
0b73059 Switch wnaf splitting from num-based to scalar-based
1e6c77c Generalize secp256k1_scalar_get_bits
5213207 Add secp256k1_scalar_add_bit
3c0ae43 Merge pull request #122
6e05287 Do signature recovery/verification with 4 possible recid case
e3d692f Explain why no y=0 check is necessary for doubling
f7dc1c6 Optimize doubling: secp256k1 has no y=0 point
666d3b5 Merge pull request #121
2a54f9b Correct typo in comment
9d64145 Merge pull request #114
99f0728 Fix secp256k1_num_set_bin handling of 0
d907ebc Add bounds checking to field element setters
bb2cd94 Merge pull request #116
665775b Don't split the g factor when not using endomorphism
9431d6b Merge pull request #115
e2274c5 build: osx: attempt to work with homebrew keg-only packages
git-subtree-dir: src/secp256k1
git-subtree-split: b0210a95da433e048a11d298efbcc14eb423c95f
Diffstat (limited to 'src/scalar.h')
-rw-r--r-- | src/scalar.h | 41 |
1 files changed, 37 insertions, 4 deletions
diff --git a/src/scalar.h b/src/scalar.h index 3baacb3721..2f5ba0d447 100644 --- a/src/scalar.h +++ b/src/scalar.h @@ -21,20 +21,32 @@ #error "Please select scalar implementation" #endif +static void secp256k1_scalar_start(void); +static void secp256k1_scalar_stop(void); + /** Clear a scalar to prevent the leak of sensitive data. */ static void secp256k1_scalar_clear(secp256k1_scalar_t *r); -/** Access bits from a scalar. */ -static int secp256k1_scalar_get_bits(const secp256k1_scalar_t *a, int offset, int count); +/** 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); + +/** 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); /** 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); +/** Set a scalar to an unsigned integer. */ +static void secp256k1_scalar_set_int(secp256k1_scalar_t *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); -/** Add two scalars together (modulo the group order). */ -static void secp256k1_scalar_add(secp256k1_scalar_t *r, const secp256k1_scalar_t *a, const secp256k1_scalar_t *b); +/** 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); + +/** 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); /** 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); @@ -45,6 +57,9 @@ static void secp256k1_scalar_sqr(secp256k1_scalar_t *r, const secp256k1_scalar_t /** Compute the inverse of a scalar (modulo the group order). */ static void secp256k1_scalar_inverse(secp256k1_scalar_t *r, const secp256k1_scalar_t *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); + /** Compute the complement of a scalar (modulo the group order). */ static void secp256k1_scalar_negate(secp256k1_scalar_t *r, const secp256k1_scalar_t *a); @@ -57,7 +72,25 @@ static int secp256k1_scalar_is_one(const secp256k1_scalar_t *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); +#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); +/** Get the order of the group as a number. */ +static void secp256k1_scalar_order_get_num(secp256k1_num_t *r); +#endif + +/** Compare two scalars. */ +static int secp256k1_scalar_eq(const secp256k1_scalar_t *a, const secp256k1_scalar_t *b); + +static void secp256k1_scalar_split_128(secp256k1_scalar_t *r1, secp256k1_scalar_t *r2, const secp256k1_scalar_t *a); + +#ifdef USE_ENDOMORPHISM +/** 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); +#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); + #endif |