Move the cubic root to GLV files

constantine.nimble

@@ -33,8 +33,7 @@ const testDesc: seq[tuple[path: string, useGMP: bool]] = @[
   ("tests/t_finite_fields_sqrt.nim", false),
   ("tests/t_finite_fields_powinv.nim", false),
   ("tests/t_finite_fields_vs_gmp.nim", true),
-  # Precompute
+  ("tests/t_fp_cubic_root.nim", false),
-  ("tests/t_precomputed", false),
   # Double-width finite fields
   ("tests/t_finite_fields_double_width.nim", false),
   # Towers of extension fields

constantine/config/curves.nim

@@ -175,16 +175,6 @@ macro getBN_param_6u_minus_1_BE*(C: static Curve): untyped =
   ## of a BN curve in canonical big-endian representation
   result = bindSym($C & "_BN_6u_minus_1_BE")
 
-# Endomorphism
-# -------------------------------------------------------
-macro getCubicRootOfUnity_mod_p*(C: static Curve): untyped =
-  ## Get a non-trivial cubic root of unity (mod p) with p the prime field
-  result = bindSym($C & "_cubicRootOfUnity_mod_p")
-
-macro getCubicRootOfUnity_mod_r*(C: static Curve): untyped =
-  ## Get a non-trivial cubic root of unity (mod r) with r the curve order
-  result = bindSym($C & "_cubicRootOfUnity_mod_r")
-
 # ############################################################
 #
 #                Debug info printed at compile-time

constantine/config/curves_declaration.nim

@@ -104,9 +104,6 @@ declareCurves:
     family: BarretoNaehrig
     bn_u_bitwidth: 63
     bn_u: "0x44e992b44a6909f1" # u: 4965661367192848881
-    cubicRootOfUnity_modP: "0x30644e72e131a0295e6dd9e7e0acccb0c28f069fbb966e3de4bd44e5607cfd48"
-    # For sanity checks
-    cubicRootOfUnity_modR: "0x30644e72e131a029048b6e193fd84104cc37a73fec2bc5e9b8ca0b2d36636f23"
 
     # G1 Equation: Y^2 = X^3 + 3
     # G2 Equation: Y^2 = X^3 + 3/(9+𝑖)
@@ -140,7 +137,6 @@ declareCurves:
     family: BarretoLynnScott
     # u: 3 * 2^46 * (7 * 13 * 499) + 1
     # u: 0x8508c00000000001
-    cubicRootOfUnity_mod_p: "0x9b3af05dd14f6ec619aaf7d34594aabc5ed1347970dec00452217cc900000008508c00000000001"
 
     # G1 Equation: y² = x³ + 1
     # G2 Equation: y² = x³ + 1/ with 𝑗 = √-5
@@ -160,7 +156,6 @@ declareCurves:
     modulus: "0x1a0111ea397fe69a4b1ba7b6434bacd764774b84f38512bf6730d2a0f6b0f6241eabfffeb153ffffb9feffffffffaaab"
     family: BarretoLynnScott
     # u: -(2^63 + 2^62 + 2^60 + 2^57 + 2^48 + 2^16)
-    cubicRootOfUnity_mod_p: "0x1a0111ea397fe699ec02408663d4de85aa0d857d89759ad4897d29650fb85f9b409427eb4f49fffd8bfd00000000aaac"
 
     # G1 Equation: y² = x³ + 4
     # G2 Equation: y² = x³ + 4 (1+i)

constantine/config/curves_derived.nim

@@ -124,34 +124,6 @@ macro genDerivedConstants*(): untyped =
       )
     )
 
-    # const MyCurve_cubicRootOfUnity_mod_p
-    block:
-      let cubicHex = ident(curve & "_cubicRootOfUnity_modP_Hex")
-      let cubic = used(curve & "_cubicRootOfUnity_mod_p")
-      let M = bindSym(curve & "_Modulus")
-      let r2modM = ident(curve & "_R2modP")
-      let m0ninv = ident(curve & "_NegInvModWord")
-      result.add quote do:
-        when declared(`cubicHex`):
-          const `cubic` = block:
-            var cubic: Fp[Curve(`curveSym`)]
-            montyResidue_precompute(
-              cubic.mres,
-              fromHex(cubic.mres.typeof, `cubicHex`),
-              `M`, `r2modM`, `m0ninv`
-            )
-            cubic
-    # const MyCurve_cubicRootOfUnity_mod_r
-    block: # For scalar decomposition sanity checks
-      let cubicHex = ident(curve & "_cubicRootOfUnity_modR_Hex")
-      let cubic = used(curve & "_cubicRootOfUnity_mod_r")
-      let getCurveOrderBitwidth = ident"getCurveOrderBitwidth"
-      result.add quote do:
-        when declared(`cubicHex`):
-          const `cubic` = fromHex(BigInt[
-            `getCurveOrderBitwidth`(Curve(`curveSym`))
-          ], `cubicHex`)
-
     if CurveFamilies[curveSym] == BarretoNaehrig:
       # when declared(MyCurve_BN_param_u):
       #   const MyCurve_BN_u_BE = toCanonicalIntRepr(MyCurve_BN_param_u)

constantine/config/curves_parser.nim

@@ -109,10 +109,6 @@ type
     sexticTwist: SexticTwist
     sexticNonResidue_fp2: NimNode # nnkPar(nnkIntLit, nnkIntLit)
 
-    # Endomorphisms
-    cubicRootOfUnity_modP: NimNode # nnkStrLit
-    cubicRootOfUnity_modR: NimNode # nnkStrLit
-
     family: CurveFamily
     # BN family
     # ------------------------
@@ -186,10 +182,6 @@ proc parseCurveDecls(defs: var seq[CurveParams], curves: NimNode) =
         params.bn_u_bitwidth = sectionVal
       elif sectionId.eqIdent"bn_u":
         params.bn_u = sectionVal
-      elif sectionId.eqident"cubicRootOfUnity_modP":
-        params.cubicRootOfUnity_modP = sectionVal
-      elif sectionId.eqident"cubicRootOfUnity_modR":
-        params.cubicRootOfUnity_modR = sectionVal
       elif sectionId.eqIdent"eq_form":
         params.eq_form = parseEnum[CurveEquationForm]($sectionVal)
       elif sectionId.eqIdent"coef_a":
@@ -323,19 +315,6 @@ proc genMainConstants(defs: var seq[CurveParams]): NimNode =
         curveDef.sexticNonResidue_fp2
       )
 
-    # Endomorphisms
-    # -----------------------------------------------
-    if not curveDef.cubicRootOfUnity_modP.isNil:
-      curveExtraStmts.add newConstStmt(
-        exported($curve & "_cubicRootOfUnity_modP_Hex"),
-        curveDef.cubicRootOfUnity_modP
-      )
-    if not curveDef.cubicRootOfUnity_modR.isNil:
-      curveExtraStmts.add newConstStmt(
-        exported($curve & "_cubicRootOfUnity_modR_Hex"),
-        curveDef.cubicRootOfUnity_modR
-      )
-
     # BN curves
     # -----------------------------------------------
     if family == BarretoNaehrig:

constantine/curves/bls12_377_glv.nim

@@ -7,12 +7,15 @@
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
 import
-  ../config/type_bigint,
+  ../config/[curves, type_bigint, type_fp],
-  ../io/io_bigints
+  ../io/[io_bigints, io_fields]
 
 # BLS12-377 G1
 # ----------------------------------------------------------------------------------------
 
+const BLS12_377_cubicRootofUnity_mod_p* =
+  Fp[BLS12_377].fromHex"0x9b3af05dd14f6ec619aaf7d34594aabc5ed1347970dec00452217cc900000008508c00000000001"
+
 const Lattice_BLS12_377_G1* = (
   # (BigInt, isNeg)
   ((BigInt[127].fromHex"0x452217cc900000010a11800000000000", false), # u² - 1

constantine/curves/bls12_381_glv.nim

@@ -7,12 +7,15 @@
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
 import
-  ../config/type_bigint,
+  ../config/[curves, type_bigint, type_fp],
-  ../io/io_bigints
+  ../io/[io_bigints, io_fields]
 
 # BLS12-381 G1
 # ----------------------------------------------------------------------------------------
 
+const BLS12_381_cubicRootOfUnity_mod_p* =
+  Fp[BLS12_381].fromHex"0x1a0111ea397fe699ec02408663d4de85aa0d857d89759ad4897d29650fb85f9b409427eb4f49fffd8bfd00000000aaac"
+
 const Lattice_BLS12_381_G1* = (
   # (BigInt, isNeg)
   ((BigInt[128].fromHex"0xac45a4010001a40200000000ffffffff", false), # u² - 1

constantine/curves/bn254_snarks_glv.nim

@@ -7,12 +7,15 @@
 # at your option. This file may not be copied, modified, or distributed except according to those terms.
 
 import
-  ../config/type_bigint,
+  ../config/[curves, type_bigint, type_fp],
-  ../io/io_bigints
+  ../io/[io_bigints, io_fields]
 
 # BN254 Snarks G1
 # ----------------------------------------------------------------------------------------
 
+const BN254_Snarks_cubicRootofUnity_mod_p* =
+  Fp[BN254_Snarks].fromHex"0x30644e72e131a0295e6dd9e7e0acccb0c28f069fbb966e3de4bd44e5607cfd48"
+
 # Chapter 6.3.1 - Guide to Pairing-based Cryptography
 const Lattice_BN254_Snarks_G1* = (
   # Curve of order 254 -> mini scalars of size 127

constantine/curves/constants_glv.nim

@@ -29,3 +29,7 @@ template lattice*(F: typedesc[Fp or Fp2]): untyped =
   const G = if F is Fp: "G1"
             else: "G2"
   dispatch("Lattice_", F.C, G)
+
+macro getCubicRootOfUnity_mod_p*(C: static Curve): untyped =
+  ## Get a non-trivial cubic root of unity (mod p) with p the prime field
+  result = bindSym($C & "_cubicRootOfUnity_mod_p")

tests/t_fp_cubic_root.nim

@@ -10,7 +10,7 @@ import  std/unittest,
         ../constantine/config/common,
         ../constantine/arithmetic,
         ../constantine/config/curves,
-        ../constantine/io/[io_bigints, io_fields]
+        ../constantine/curves/constants_glv
 
 echo "\n------------------------------------------------------\n"
 
@@ -22,19 +22,10 @@ proc checkCubeRootOfUnity(curve: static Curve) =
 
     check: bool cru.isOne()
 
-  test $curve & " cube root of unity (mod r)":
-    var cru: BigInt[3 * curve.getCurveOrderBitwidth()]
-    cru.prod(curve.getCubicRootOfUnity_mod_r(), curve.getCubicRootOfUnity_mod_r())
-    cru.mul(curve.getCubicRootOfUnity_mod_r())
-
-    var r: BigInt[curve.getCurveOrderBitwidth()]
-    r.reduce(cru, curve.getCurveOrder)
-
-    check: bool r.isOne()
-
 proc main() =
   suite "Sanity checks on precomputed values" & " [" & $WordBitwidth & "-bit mode]":
     checkCubeRootOfUnity(BN254_Snarks)
-    # checkCubeRootOfUnity(BLS12_381)
+    checkCubeRootOfUnity(BLS12_377)
+    checkCubeRootOfUnity(BLS12_381)
 
 main()