def subl_okb

bend-collections-laws-crypto@1.0.0.0 · proofs/crypto/curve25519/fieldops.bend:106

import Base
import bend-collections-laws-crypto@1.0.0.0/src/crypto/curve25519/field.bend as F
import bend-collections-laws-crypto@1.0.0.0/proofs/lib/nat.bend as N
import bend-collections-laws-crypto@1.0.0.0/proofs/lib/logic.bend as L
import bend-collections-laws-crypto@1.0.0.0/proofs/lib/word.bend as WD
import bend-collections-laws-crypto@1.0.0.0/proofs/crypto/curve25519/num.bend as M
import bend-collections-laws-crypto@1.0.0.0/proofs/crypto/curve25519/limbs.bend as LM

106def subl_okb(+one: Nat, +h1: {one == 1n : Nat}, +n: Nat, +xs: List<&2, U32>, +ys: List<&2, U32>, +ks: List<&2, U32>, +bx: Nat, +by: Nat, +bk: Nat, +hx: {LM.okb(n, xs, bx) == True{} : Bool}, +hy: {LM.okb(n, ys, by) == True{} : Bool}, +hk: {LM.okb(n, ks, bk) == True{} : Bool}, +hg: {gea(ks, by) == True{} : Bool}, +hb: {Nat.is_lt(Nat.add(bx, bk), WD.sc(32n, one)) == True{} : Bool}) -> {LM.okb(n, F.subl(xs, ys, ks), Nat.add(bx, bk)) == True{} : Bool}:
107  match n xs ys ks:
108    case 0n Nil{} _ _:
109      {==}
110    case 0n Con{x, xt} _ _:
111      Empty.absurd({LM.okb(0n, F.subl(Con{x, xt}, ys, ks), Nat.add(bx, bk)) == True{} : Bool}, L.false_true(hx))
112    case 1n+m Nil{} _ _:
113      Empty.absurd({LM.okb(1n+m, Nil{}, Nat.add(bx, bk)) == True{} : Bool}, L.false_true(hx))
114    case 1n+m Con{x, xt} Nil{} _:
115      Empty.absurd({LM.okb(1n+m, Nil{}, Nat.add(bx, bk)) == True{} : Bool}, L.false_true(hy))
116    case 1n+m Con{x, xt} Con{y, yt} Nil{}:
117      Empty.absurd({LM.okb(1n+m, Nil{}, Nat.add(bx, bk)) == True{} : Bool}, L.false_true(hk))
118    case 1n+ +m Con{+x, +xt} Con{+y, +yt} Con{+k, +kt}:
119      +s = U32.sub(U32.add(x, k), y)
120      +hxh = LM.okb_head(m, x, xt, bx, hx)
121      +hkh = LM.okb_head(m, k, kt, bk, hk)
122      +el = subl_v(one, h1, x, y, k, bx, by, bk, hxh, LM.okb_head(m, y, yt, by, hy), hkh, gea_head(k, kt, by, hg), hb)
123      +le1 = L.subst(Nat, z => {Nat.is_le(v(s), z) == True{} : Bool}, Nat.add(v(s), v(y)), Nat.add(v(x), v(k)), el, N.le_add_right(v(s), v(y)))
124      +le2 = N.le_trans(v(s), Nat.add(v(x), v(k)), Nat.add(bx, bk), le1, M.le_add2(v(x), v(k), bx, bk, hxh, hkh))
125      L.and_intro(Nat.is_le(v(s), Nat.add(bx, bk)), LM.okb(m, F.subl(xt, yt, kt), Nat.add(bx, bk)), le2, subl_okb(one, h1, m, xt, yt, kt, bx, by, bk, LM.okb_tail(m, x, xt, bx, hx), LM.okb_tail(m, y, yt, by, hy), LM.okb_tail(m, k, kt, bk, hk), gea_tail(k, kt, by, hg), hb))