@kotevode/ffjavascript/src/wasm_curve.js

Finite Field Library in Javascript

import * as Scalar from "./scalar.js";
import buildBatchConvert from "./engine_batchconvert.js";

export default class WasmCurve {

    constructor(tm, prefix, F, pGen, pGb, cofactor) {
        this.tm = tm;
        this.prefix = prefix;
        this.F = F;

        this.pOp1 = tm.alloc(F.n8*3);
        this.pOp2 = tm.alloc(F.n8*3);
        this.pOp3 = tm.alloc(F.n8*3);
        this.tm.instance.exports[prefix + "_zero"](this.pOp1);
        this.zero = this.tm.getBuff(this.pOp1, F.n8*3);
        this.tm.instance.exports[prefix + "_zeroAffine"](this.pOp1);
        this.zeroAffine = this.tm.getBuff(this.pOp1, F.n8*2);
        this.one = this.tm.getBuff(pGen, F.n8*3);
        this.g = this.one;
        this.oneAffine = this.tm.getBuff(pGen, F.n8*2);
        this.gAffine = this.oneAffine;
        this.b = this.tm.getBuff(pGb, F.n8);

        if (cofactor) {
            this.cofactor = Scalar.toLEBuff(cofactor);
        }

        this.negone = this.neg(this.one);
        this.two = this.add(this.one, this.one);

        this.batchLEMtoC = buildBatchConvert(tm, prefix + "_batchLEMtoC", F.n8*2, F.n8);
        this.batchLEMtoU = buildBatchConvert(tm, prefix + "_batchLEMtoU", F.n8*2, F.n8*2);
        this.batchCtoLEM = buildBatchConvert(tm, prefix + "_batchCtoLEM", F.n8, F.n8*2);
        this.batchUtoLEM = buildBatchConvert(tm, prefix + "_batchUtoLEM", F.n8*2, F.n8*2);
        this.batchToJacobian = buildBatchConvert(tm, prefix + "_batchToJacobian", F.n8*2, F.n8*3);
        this.batchToAffine = buildBatchConvert(tm, prefix + "_batchToAffine", F.n8*3, F.n8*2);
    }

    op2(opName, a, b) {
        this.tm.setBuff(this.pOp1, a);
        this.tm.setBuff(this.pOp2, b);
        this.tm.instance.exports[this.prefix + opName](this.pOp1, this.pOp2, this.pOp3);
        return this.tm.getBuff(this.pOp3, this.F.n8*3);
    }

    op2bool(opName, a, b) {
        this.tm.setBuff(this.pOp1, a);
        this.tm.setBuff(this.pOp2, b);
        return !!this.tm.instance.exports[this.prefix + opName](this.pOp1, this.pOp2, this.pOp3);
    }

    op1(opName, a) {
        this.tm.setBuff(this.pOp1, a);
        this.tm.instance.exports[this.prefix + opName](this.pOp1, this.pOp3);
        return this.tm.getBuff(this.pOp3, this.F.n8*3);
    }

    op1Affine(opName, a) {
        this.tm.setBuff(this.pOp1, a);
        this.tm.instance.exports[this.prefix + opName](this.pOp1, this.pOp3);
        return this.tm.getBuff(this.pOp3, this.F.n8*2);
    }

    op1Bool(opName, a) {
        this.tm.setBuff(this.pOp1, a);
        return !!this.tm.instance.exports[this.prefix + opName](this.pOp1, this.pOp3);
    }

    add(a,b) {
        if (a.byteLength == this.F.n8*3) {
            if (b.byteLength == this.F.n8*3) {
                return this.op2("_add", a, b);
            } else if (b.byteLength == this.F.n8*2) {
                return this.op2("_addMixed", a, b);
            } else {
                throw new Error("invalid point size");
            }
        } else if (a.byteLength == this.F.n8*2) {
            if (b.byteLength == this.F.n8*3) {
                return this.op2("_addMixed", b, a);
            } else if (b.byteLength == this.F.n8*2) {
                return this.op2("_addAffine", a, b);
            } else {
                throw new Error("invalid point size");
            }
        } else {
            throw new Error("invalid point size");
        }
    }

    sub(a,b) {
        if (a.byteLength == this.F.n8*3) {
            if (b.byteLength == this.F.n8*3) {
                return this.op2("_sub", a, b);
            } else if (b.byteLength == this.F.n8*2) {
                return this.op2("_subMixed", a, b);
            } else {
                throw new Error("invalid point size");
            }
        } else if (a.byteLength == this.F.n8*2) {
            if (b.byteLength == this.F.n8*3) {
                return this.op2("_subMixed", b, a);
            } else if (b.byteLength == this.F.n8*2) {
                return this.op2("_subAffine", a, b);
            } else {
                throw new Error("invalid point size");
            }
        } else {
            throw new Error("invalid point size");
        }
    }

    neg(a) {
        if (a.byteLength == this.F.n8*3) {
            return this.op1("_neg", a);
        } else if (a.byteLength == this.F.n8*2) {
            return this.op1Affine("_negAffine", a);
        } else {
            throw new Error("invalid point size");
        }
    }

    double(a) {
        if (a.byteLength == this.F.n8*3) {
            return this.op1("_double", a);
        } else if (a.byteLength == this.F.n8*2) {
            return this.op1("_doubleAffine", a);
        } else {
            throw new Error("invalid point size");
        }
    }

    isZero(a) {
        if (a.byteLength == this.F.n8*3) {
            return this.op1Bool("_isZero", a);
        } else if (a.byteLength == this.F.n8*2) {
            return this.op1Bool("_isZeroAffine", a);
        } else {
            throw new Error("invalid point size");
        }
    }

    timesScalar(a, s) {
        if (!(s instanceof Uint8Array)) {
            s = Scalar.toLEBuff(Scalar.e(s));
        }
        let fnName;
        if (a.byteLength == this.F.n8*3) {
            fnName = this.prefix + "_timesScalar";
        } else if (a.byteLength == this.F.n8*2) {
            fnName = this.prefix + "_timesScalarAffine";
        } else {
            throw new Error("invalid point size");
        }
        this.tm.setBuff(this.pOp1, a);
        this.tm.setBuff(this.pOp2, s);
        this.tm.instance.exports[fnName](this.pOp1, this.pOp2, s.byteLength, this.pOp3);
        return this.tm.getBuff(this.pOp3, this.F.n8*3);
    }

    timesFr(a, s) {
        let fnName;
        if (a.byteLength == this.F.n8*3) {
            fnName = this.prefix + "_timesFr";
        } else if (a.byteLength == this.F.n8*2) {
            fnName = this.prefix + "_timesFrAffine";
        } else {
            throw new Error("invalid point size");
        }
        this.tm.setBuff(this.pOp1, a);
        this.tm.setBuff(this.pOp2, s);
        this.tm.instance.exports[fnName](this.pOp1, this.pOp2, this.pOp3);
        return this.tm.getBuff(this.pOp3, this.F.n8*3);
    }

    eq(a,b) {
        if (a.byteLength == this.F.n8*3) {
            if (b.byteLength == this.F.n8*3) {
                return this.op2bool("_eq", a, b);
            } else if (b.byteLength == this.F.n8*2) {
                return this.op2bool("_eqMixed", a, b);
            } else {
                throw new Error("invalid point size");
            }
        } else if (a.byteLength == this.F.n8*2) {
            if (b.byteLength == this.F.n8*3) {
                return this.op2bool("_eqMixed", b, a);
            } else if (b.byteLength == this.F.n8*2) {
                return this.op2bool("_eqAffine", a, b);
            } else {
                throw new Error("invalid point size");
            }
        } else {
            throw new Error("invalid point size");
        }
    }

    toAffine(a) {
        if (a.byteLength == this.F.n8*3) {
            return this.op1Affine("_toAffine", a);
        } else if (a.byteLength == this.F.n8*2) {
            return a;
        } else {
            throw new Error("invalid point size");
        }
    }

    toJacobian(a) {
        if (a.byteLength == this.F.n8*3) {
            return a;
        } else if (a.byteLength == this.F.n8*2) {
            return this.op1("_toJacobian", a);
        } else {
            throw new Error("invalid point size");
        }
    }

    toRprUncompressed(arr, offset, a) {
        this.tm.setBuff(this.pOp1, a);
        if (a.byteLength == this.F.n8*3) {
            this.tm.instance.exports[this.prefix + "_toAffine"](this.pOp1, this.pOp1);
        } else if (a.byteLength != this.F.n8*2) {
            throw new Error("invalid point size");
        }
        this.tm.instance.exports[this.prefix + "_LEMtoU"](this.pOp1, this.pOp1);
        const res = this.tm.getBuff(this.pOp1, this.F.n8*2);
        arr.set(res, offset);
    }

    fromRprUncompressed(arr, offset) {
        const buff = arr.slice(offset, offset + this.F.n8*2);
        this.tm.setBuff(this.pOp1, buff);
        this.tm.instance.exports[this.prefix + "_UtoLEM"](this.pOp1, this.pOp1);
        return this.tm.getBuff(this.pOp1, this.F.n8*2);
    }

    toRprCompressed(arr, offset, a) {
        this.tm.setBuff(this.pOp1, a);
        if (a.byteLength == this.F.n8*3) {
            this.tm.instance.exports[this.prefix + "_toAffine"](this.pOp1, this.pOp1);
        } else if (a.byteLength != this.F.n8*2) {
            throw new Error("invalid point size");
        }
        this.tm.instance.exports[this.prefix + "_LEMtoC"](this.pOp1, this.pOp1);
        const res = this.tm.getBuff(this.pOp1, this.F.n8);
        arr.set(res, offset);
    }

    fromRprCompressed(arr, offset) {
        const buff = arr.slice(offset, offset + this.F.n8);
        this.tm.setBuff(this.pOp1, buff);
        this.tm.instance.exports[this.prefix + "_CtoLEM"](this.pOp1, this.pOp2);
        return this.tm.getBuff(this.pOp2, this.F.n8*2);
    }

    toUncompressed(a) {
        const buff = new Uint8Array(this.F.n8*2);
        this.toRprUncompressed(buff, 0, a);
        return buff;
    }

    toRprLEM(arr, offset, a) {
        if (a.byteLength == this.F.n8*2) {
            arr.set(a, offset);
            return;
        } else if (a.byteLength == this.F.n8*3) {
            this.tm.setBuff(this.pOp1, a);
            this.tm.instance.exports[this.prefix + "_toAffine"](this.pOp1, this.pOp1);
            const res = this.tm.getBuff(this.pOp1, this.F.n8*2);
            arr.set(res, offset);
        } else {
            throw new Error("invalid point size");
        }
    }

    fromRprLEM(arr, offset) {
        offset = offset || 0;
        return arr.slice(offset, offset+this.F.n8*2);
    }

    toString(a, radix) {
        if (a.byteLength == this.F.n8*3) {
            const x = this.F.toString(a.slice(0, this.F.n8), radix);
            const y = this.F.toString(a.slice(this.F.n8, this.F.n8*2), radix);
            const z = this.F.toString(a.slice(this.F.n8*2), radix);
            return `[ ${x}, ${y}, ${z} ]`;
        } else if (a.byteLength == this.F.n8*2) {
            const x = this.F.toString(a.slice(0, this.F.n8), radix);
            const y = this.F.toString(a.slice(this.F.n8), radix);
            return `[ ${x}, ${y} ]`;
        } else {
            throw new Error("invalid point size");
        }
    }

    isValid(a) {
        if (this.isZero(a)) return true;
        const F = this.F;
        const aa = this.toAffine(a);
        const x = aa.slice(0, this.F.n8);
        const y = aa.slice(this.F.n8, this.F.n8*2);
        const x3b = F.add(F.mul(F.square(x),x), this.b);
        const y2 = F.square(y);
        return F.eq(x3b, y2);
    }

    fromRng(rng) {
        const F = this.F;
        let P = [];
        let greatest;
        let x3b;
        do {
            P[0] = F.fromRng(rng);
            greatest = rng.nextBool();
            x3b = F.add(F.mul(F.square(P[0]), P[0]), this.b);
        } while (!F.isSquare(x3b));

        P[1] = F.sqrt(x3b);

        const s = F.isNegative(P[1]);
        if (greatest ^ s) P[1] = F.neg(P[1]);

        let Pbuff = new Uint8Array(this.F.n8*2);
        Pbuff.set(P[0]);
        Pbuff.set(P[1], this.F.n8);

        if (this.cofactor) {
            Pbuff = this.timesScalar(Pbuff, this.cofactor);
        }

        return Pbuff;
    }



    toObject(a) {
        if (this.isZero(a)) {
            return [
                this.F.toObject(this.F.zero),
                this.F.toObject(this.F.one),
                this.F.toObject(this.F.zero),
            ];
        }
        const x = this.F.toObject(a.slice(0, this.F.n8));
        const y = this.F.toObject(a.slice(this.F.n8, this.F.n8*2));
        let z;
        if (a.byteLength == this.F.n8*3) {
            z = this.F.toObject(a.slice(this.F.n8*2, this.F.n8*3));
        } else {
            z = this.F.toObject(this.F.one);
        }
        return [x, y, z];
    }

    fromObject(a) {
        const x = this.F.fromObject(a[0]);
        const y = this.F.fromObject(a[1]);
        let z;
        if (a.length==3) {
            z = this.F.fromObject(a[2]);
        } else {
            z = this.F.one;
        }
        if (this.F.isZero(z, this.F.one)) {
            return this.zeroAffine;
        } else if (this.F.eq(z, this.F.one)) {
            const buff = new Uint8Array(this.F.n8*2);
            buff.set(x);
            buff.set(y, this.F.n8);
            return buff;
        } else {
            const buff = new Uint8Array(this.F.n8*3);
            buff.set(x);
            buff.set(y, this.F.n8);
            buff.set(z, this.F.n8*2);
            return buff;
        }
    }

    e(a) {
        if (a instanceof Uint8Array) return a;
        return this.fromObject(a);
    }

    x(a) {
        const tmp = this.toAffine(a);
        return tmp.slice(0, this.F.n8);
    }

    y(a) {
        const tmp = this.toAffine(a);
        return tmp.slice(this.F.n8);
    }

}