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7a49cac Merge #410: Add string.h include to ecmult_impl 0bbd5d4 Add string.h include to ecmult_impl c5b32e1 Merge #405: Make secp256k1_fe_sqrt constant time 926836a Make secp256k1_fe_sqrt constant time e2a8e92 Merge #404: Replace 3M + 4S doubling formula with 2M + 5S one 8ec49d8 Add note about 2M + 5S doubling formula 5a91bd7 Merge #400: A couple minor cleanups ac01378 build: add -DSECP256K1_BUILD to benchmark_internal build flags a6c6f99 Remove a bunch of unused stdlib #includes 65285a6 Merge #403: configure: add flag to disable OpenSSL tests a9b2a5d configure: add flag to disable OpenSSL tests b340123 Merge #402: Add support for testing quadratic residues e6e9805 Add function for testing quadratic residue field/group elements. efd953a Add Jacobi symbol test via GMP fa36a0d Merge #401: ecmult_const: unify endomorphism and non-endomorphism skew cases c6191fd ecmult_const: unify endomorphism and non-endomorphism skew cases 0b3e618 Merge #378: .gitignore build-aux cleanup 6042217 Merge #384: JNI: align shared files copyright/comments to bitcoinj's 24ad20f Merge #399: build: verify that the native compiler works for static precomp b3be852 Merge #398: Test whether ECDH and Schnorr are enabled for JNI aa0b1fd build: verify that the native compiler works for static precomp eee808d Test whether ECDH and Schnorr are enabled for JNI 7b0fb18 Merge #366: ARM assembly implementation of field_10x26 inner (rebase of #173) 001f176 ARM assembly implementation of field_10x26 inner 0172be9 Merge #397: Small fixes for sha256 3f8b78e Fix undefs in hash_impl.h 2ab4695 Fix state size in sha256 struct 6875b01 Merge #386: Add some missing `VERIFY_CHECK(ctx != NULL)` 2c52b5d Merge #389: Cast pointers through uintptr_t under JNI 43097a4 Merge #390: Update bitcoin-core GitHub links 31c9c12 Merge #391: JNI: Only call ecdsa_verify if its inputs parsed correctly 1cb2302 Merge #392: Add testcase which hits additional branch in secp256k1_scalar_sqr d2ee340 Merge #388: bench_ecdh: fix call to secp256k1_context_create 093a497 Add testcase which hits additional branch in secp256k1_scalar_sqr a40c701 JNI: Only call ecdsa_verify if its inputs parsed correctly faa2a11 Update bitcoin-core GitHub links 47b9e78 Cast pointers through uintptr_t under JNI f36f9c6 bench_ecdh: fix call to secp256k1_context_create bcc4881 Add some missing `VERIFY_CHECK(ctx != NULL)` for functions that use `ARG_CHECK` 6ceea2c align shared files copyright/comments to bitcoinj's 70141a8 Update .gitignore 7b549b1 Merge #373: build: fix x86_64 asm detection for some compilers bc7c93c Merge #374: Add note about y=0 being possible on one of the sextic twists e457018 Merge #364: JNI rebased 86e2d07 JNI library: cleanup, removed unimplemented code 3093576a JNI library bd2895f Merge pull request #371 e72e93a Add note about y=0 being possible on one of the sextic twists 3f8fdfb build: fix x86_64 asm detection for some compilers e5a9047 [Trivial] Remove double semicolons c18b869 Merge pull request #360 3026daa Merge pull request #302 03d4611 Add sage verification script for the group laws a965937 Merge pull request #361 83221ec Add experimental features to configure 5d4c5a3 Prevent damage_array in the signature test from going out of bounds. 419bf7f Merge pull request #356 03d84a4 Benchmark against OpenSSL verification git-subtree-dir: src/secp256k1 git-subtree-split: 7a49cacd3937311fcb1cb36b6ba3336fca811991
128 lines
6.2 KiB
C
128 lines
6.2 KiB
C
/**********************************************************************
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* Copyright (c) 2013, 2014 Pieter Wuille *
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* Distributed under the MIT software license, see the accompanying *
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* file COPYING or http://www.opensource.org/licenses/mit-license.php.*
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**********************************************************************/
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#ifndef _SECP256K1_FIELD_
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#define _SECP256K1_FIELD_
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/** Field element module.
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*
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* Field elements can be represented in several ways, but code accessing
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* it (and implementations) need to take certain properties into account:
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* - Each field element can be normalized or not.
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* - Each field element has a magnitude, which represents how far away
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* its representation is away from normalization. Normalized elements
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* always have a magnitude of 1, but a magnitude of 1 doesn't imply
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* normality.
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*/
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#if defined HAVE_CONFIG_H
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#include "libsecp256k1-config.h"
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#endif
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#if defined(USE_FIELD_10X26)
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#include "field_10x26.h"
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#elif defined(USE_FIELD_5X52)
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#include "field_5x52.h"
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#else
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#error "Please select field implementation"
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#endif
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/** Normalize a field element. */
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static void secp256k1_fe_normalize(secp256k1_fe *r);
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/** Weakly normalize a field element: reduce it magnitude to 1, but don't fully normalize. */
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static void secp256k1_fe_normalize_weak(secp256k1_fe *r);
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/** Normalize a field element, without constant-time guarantee. */
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static void secp256k1_fe_normalize_var(secp256k1_fe *r);
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/** Verify whether a field element represents zero i.e. would normalize to a zero value. The field
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* implementation may optionally normalize the input, but this should not be relied upon. */
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static int secp256k1_fe_normalizes_to_zero(secp256k1_fe *r);
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/** Verify whether a field element represents zero i.e. would normalize to a zero value. The field
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* implementation may optionally normalize the input, but this should not be relied upon. */
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static int secp256k1_fe_normalizes_to_zero_var(secp256k1_fe *r);
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/** Set a field element equal to a small integer. Resulting field element is normalized. */
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static void secp256k1_fe_set_int(secp256k1_fe *r, int a);
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/** Verify whether a field element is zero. Requires the input to be normalized. */
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static int secp256k1_fe_is_zero(const secp256k1_fe *a);
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/** Check the "oddness" of a field element. Requires the input to be normalized. */
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static int secp256k1_fe_is_odd(const secp256k1_fe *a);
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/** Compare two field elements. Requires magnitude-1 inputs. */
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static int secp256k1_fe_equal(const secp256k1_fe *a, const secp256k1_fe *b);
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/** Same as secp256k1_fe_equal, but may be variable time. */
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static int secp256k1_fe_equal_var(const secp256k1_fe *a, const secp256k1_fe *b);
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/** Compare two field elements. Requires both inputs to be normalized */
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static int secp256k1_fe_cmp_var(const secp256k1_fe *a, const secp256k1_fe *b);
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/** Set a field element equal to 32-byte big endian value. If successful, the resulting field element is normalized. */
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static int secp256k1_fe_set_b32(secp256k1_fe *r, const unsigned char *a);
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/** Convert a field element to a 32-byte big endian value. Requires the input to be normalized */
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static void secp256k1_fe_get_b32(unsigned char *r, const secp256k1_fe *a);
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/** Set a field element equal to the additive inverse of another. Takes a maximum magnitude of the input
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* as an argument. The magnitude of the output is one higher. */
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static void secp256k1_fe_negate(secp256k1_fe *r, const secp256k1_fe *a, int m);
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/** Multiplies the passed field element with a small integer constant. Multiplies the magnitude by that
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* small integer. */
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static void secp256k1_fe_mul_int(secp256k1_fe *r, int a);
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/** Adds a field element to another. The result has the sum of the inputs' magnitudes as magnitude. */
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static void secp256k1_fe_add(secp256k1_fe *r, const secp256k1_fe *a);
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/** Sets a field element to be the product of two others. Requires the inputs' magnitudes to be at most 8.
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* The output magnitude is 1 (but not guaranteed to be normalized). */
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static void secp256k1_fe_mul(secp256k1_fe *r, const secp256k1_fe *a, const secp256k1_fe * SECP256K1_RESTRICT b);
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/** Sets a field element to be the square of another. Requires the input's magnitude to be at most 8.
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* The output magnitude is 1 (but not guaranteed to be normalized). */
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static void secp256k1_fe_sqr(secp256k1_fe *r, const secp256k1_fe *a);
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/** If a has a square root, it is computed in r and 1 is returned. If a does not
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* have a square root, the root of its negation is computed and 0 is returned.
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* The input's magnitude can be at most 8. The output magnitude is 1 (but not
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* guaranteed to be normalized). The result in r will always be a square
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* itself. */
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static int secp256k1_fe_sqrt(secp256k1_fe *r, const secp256k1_fe *a);
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/** Checks whether a field element is a quadratic residue. */
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static int secp256k1_fe_is_quad_var(const secp256k1_fe *a);
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/** Sets a field element to be the (modular) inverse of another. Requires the input's magnitude to be
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* at most 8. The output magnitude is 1 (but not guaranteed to be normalized). */
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static void secp256k1_fe_inv(secp256k1_fe *r, const secp256k1_fe *a);
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/** Potentially faster version of secp256k1_fe_inv, without constant-time guarantee. */
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static void secp256k1_fe_inv_var(secp256k1_fe *r, const secp256k1_fe *a);
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/** Calculate the (modular) inverses of a batch of field elements. Requires the inputs' magnitudes to be
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* at most 8. The output magnitudes are 1 (but not guaranteed to be normalized). The inputs and
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* outputs must not overlap in memory. */
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static void secp256k1_fe_inv_all_var(size_t len, secp256k1_fe *r, const secp256k1_fe *a);
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/** Convert a field element to the storage type. */
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static void secp256k1_fe_to_storage(secp256k1_fe_storage *r, const secp256k1_fe *a);
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/** Convert a field element back from the storage type. */
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static void secp256k1_fe_from_storage(secp256k1_fe *r, const secp256k1_fe_storage *a);
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/** If flag is true, set *r equal to *a; otherwise leave it. Constant-time. */
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static void secp256k1_fe_storage_cmov(secp256k1_fe_storage *r, const secp256k1_fe_storage *a, int flag);
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/** If flag is true, set *r equal to *a; otherwise leave it. Constant-time. */
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static void secp256k1_fe_cmov(secp256k1_fe *r, const secp256k1_fe *a, int flag);
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#endif
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