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4ff0e3d90b
* Lay out the refactoring objectives and tradeoffs * Refactor the 32 and 64-bit primitives [skip ci] * BigInts and Modular BigInts compile * Make the bigints test compile * Fix modular reduction * Fix reduction tests vs GMP * Implement montegomery mul, pow, inverse, WIP finite field compilation * Make FiniteField compile * Fix exponentiation compilation * Fix Montgomery magic constant computation for 2^64 words * Fix typo in non-optimized CIOS - passing finite fields IO tests * Add limbs comparisons [skip ci] * Fix on precomputation of the Montgomery magic constant * Passing all tests including 𝔽p2 * modular addition, the test for mersenne prime was wrong * update benches * Fix "nimble test" + typo on out-of-place field addition * bigint division, normalization is needed: https://travis-ci.com/github/mratsim/constantine/jobs/298359743 * missing conversion in subborrow non-x86 fallback - https://travis-ci.com/github/mratsim/constantine/jobs/298359744 * Fix little-endian serialization * Constantine32 flag to run 32-bit constantine on 64-bit machines * IO Field test, ensure that BaseType is used instead of uint64 when the prime can field in uint32 * Implement proper addcarry and subborrow fallback for the compile-time VM * Fix export issue when the logical wordbitwidth == physical wordbitwidth - passes all tests (32-bit and 64-bit) * Fix uint128 on ARM * Fix C++ conditional copy and ARM addcarry/subborrow * Add investigation for SIGFPE in Travis * Fix debug display for unsafeDiv2n1n * multiplexer typo * moveMem bug in glibc of Ubuntu 16.04? * Was probably missing an early clobbered register annotation on conditional mov * Note on Montgomery-friendly moduli * Strongly suspect a GCC before GCC 7 codegen bug (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87139) * hex conversion was (for debugging) not taking requested order into account + inlining comment * Use 32-bit limbs on ARM64, uint128 builtin __udivti4 bug? * Revert "Use 32-bit limbs on ARM64, uint128 builtin __udivti4 bug?" This reverts commit 087f9aa7fb40bbd058d05cbd8eec7fc082911f49. * Fix subborrow fallback for non-x86 (need to maks the borrow)
103 lines
3.3 KiB
Nim
103 lines
3.3 KiB
Nim
# Constantine
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# Copyright (c) 2018-2019 Status Research & Development GmbH
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# Copyright (c) 2020-Present Mamy André-Ratsimbazafy
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# Licensed and distributed under either of
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# * MIT license (license terms in the root directory or at http://opensource.org/licenses/MIT).
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# * Apache v2 license (license terms in the root directory or at http://www.apache.org/licenses/LICENSE-2.0).
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# at your option. This file may not be copied, modified, or distributed except according to those terms.
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import
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../constantine/arithmetic/bigints,
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../constantine/config/[common, curves]
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# ############################################################
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#
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# Pseudo-Random Number Generator
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#
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# ############################################################
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#
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# Our field elements for elliptic curve cryptography
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# are in the 2^256~2^512 range.
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# For pairings, with embedding degrees of 12 to 48
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# We would need 12~48 field elements per point on the curve
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#
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# The recommendation by Vigna at http://prng.di.unimi.it
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# is to have a period of t^2 if we need t values (i.e. about 2^1024)
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# but also that for all practical purposes 2^256 period is enough
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#
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# We use 2^512 to cover the range the base field elements
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type RngState* = object
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s: array[8, uint64]
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func splitMix64(state: var uint64): uint64 =
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state += 0x9e3779b97f4a7c15'u64
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result = state
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result = (result xor (result shr 30)) * 0xbf58476d1ce4e5b9'u64
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result = (result xor (result shr 27)) * 0xbf58476d1ce4e5b9'u64
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result = result xor (result shr 31)
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func seed*(rng: var RngState, x: SomeInteger) =
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## Seed the random number generator with a fixed seed
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var sm64 = uint64(x)
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rng.s[0] = splitMix64(sm64)
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rng.s[1] = splitMix64(sm64)
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rng.s[2] = splitMix64(sm64)
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rng.s[3] = splitMix64(sm64)
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rng.s[4] = splitMix64(sm64)
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rng.s[5] = splitMix64(sm64)
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rng.s[6] = splitMix64(sm64)
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rng.s[7] = splitMix64(sm64)
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func rotl(x: uint64, k: static int): uint64 {.inline.} =
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return (x shl k) or (x shr (64 - k))
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template `^=`(x: var uint64, y: uint64) =
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x = x xor y
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func next(rng: var RngState): uint64 =
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## Compute a random uint64 from the input state
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## using xoshiro512** algorithm by Vigna et al
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## State is updated.
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result = rotl(rng.s[1] * 5, 7) * 9
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let t = rng.s[1] shl 11
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rng.s[2] ^= rng.s[0];
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rng.s[5] ^= rng.s[1];
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rng.s[1] ^= rng.s[2];
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rng.s[7] ^= rng.s[3];
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rng.s[3] ^= rng.s[4];
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rng.s[4] ^= rng.s[5];
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rng.s[0] ^= rng.s[6];
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rng.s[6] ^= rng.s[7];
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rng.s[6] ^= t;
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rng.s[7] = rotl(rng.s[7], 21);
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# ############################################################
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#
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# Create a random BigInt or Field element
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#
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# ############################################################
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func random[T](rng: var RngState, a: var T, C: static Curve) {.noInit.}=
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## Recursively initialize a BigInt or Field element
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when T is BigInt:
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var reduced, unreduced{.noInit.}: T
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for i in 0 ..< unreduced.limbs.len:
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unreduced.limbs[i] = Word(rng.next())
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# Note: a simple modulo will be biaised but it's simple and "fast"
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reduced.reduce(unreduced, C.Mod.mres)
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a.montyResidue(reduced, C.Mod.mres, C.getR2modP(), C.getNegInvModWord(), C.canUseNoCarryMontyMul())
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else:
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for field in fields(a):
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rng.random(field, C)
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func random*(rng: var RngState, T: typedesc): T =
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## Create a random Field or Extension FIeld Element
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rng.random(result, T.C)
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