Merge pull request #270 from yusufidimaina9989/master

add modEXP

src/contracts/modEXP.ts

@@ -0,0 +1,43 @@
+import { SmartContract, assert, method, prop } from "scrypt-ts";
+
+export class ModExp extends SmartContract {
+ // max # of bits for e = ceil(log2(y))
+ static readonly N : bigint = 232n;
+ // modulus
+ @prop()
+ readonly M : bigint;
+
+ constructor(M : bigint){
+ super(...arguments)
+ this.M = M
+ }
+ // x^y % M
+ @method()
+ modExp(x : bigint, y : bigint) : bigint {
+ let res : bigint = 1n;
+ x = x % this.M;
+
+ if (x != 0n) {
+ for (let i = 0; i < this.M; i ++) {
+ if (y >= 0n) {
+ // If y is odd, multiply x with result
+ if (y % 2n) res = (res * x) % this.M;
+
+ // y >> 1
+ y = y / 2n;
+ x = (x * x) % this.M;
+ }
+ }
+ }
+ else {
+ res = 0n;
+ }
+
+ return res;
+ }
+
+ @method()
+ public main(x : bigint, y : bigint, z : bigint) {
+ assert(z == this.modExp(x, y));
+ }
+}

tests/numberGuess.test.ts

@@ -23,9 +23,9 @@ async function main() {
  console.log('NumberGuess contract deployed: ', deployTx.id)
 
  const { tx: callTx, atInputIndex } = await numbergs.methods.guess(
- (sigResps) => findSig(sigResps, publicKeyalice && publicKeybob),
+ (sigResps) => findSig(sigResps, publicKeybob),
  {
- pubKeyOrAddrToSign: publicKeyalice && publicKeybob,
+ pubKeyOrAddrToSign: publicKeybob,
  } as MethodCallOptions<NumberGuess>
  )
  console.log('NumberGuess contract called: ', callTx.id)