#226 Update Project ID Derivation

backend/src/angor/AngorTransactionDecoder.ts

@@ -357,8 +357,9 @@ export class AngorTransactionDecoder {
    * @returns an integer that is derived from integer representation of founder key hash.
    */
   private getProjectIdDerivation(founderKeyHashInt: number): number {
-    // The max size of bip32 derivation range is 2,147,483,648 (2^31) the max number of uint is 4,294,967,295 so we must to divide by 2 and round it to the floor.
-    const retention = Math.floor(founderKeyHashInt / 2);
+    const intMaxValue = 0x7FFFFFFF;
+
+    const retention = founderKeyHashInt & intMaxValue;
 
     if (retention > Math.pow(2, 31)) {
       throw new Error(

backend/src/angor/tests/AngorTransactionDecoder.test.ts

@@ -6,7 +6,6 @@ import {
 import * as bitcoinJS from 'bitcoinjs-lib';
 import AngorProjectRepository from '../../repositories/AngorProjectRepository';
 import AngorInvestmentRepository from '../../repositories/AngorInvestmentRepository';
-import DB from '../../database';
 
 describe('AngorTransactionDecoder', () => {
   describe('Decoding transaction for Angor project creation', () => {
@@ -18,8 +17,8 @@ describe('AngorTransactionDecoder', () => {
       founderKeyHashHex:
         '68828edc1c6312c915c8967475be57f42d45764105af8216f2da7170d033240a',
       founderKeyHashInt: 3493012490,
-      projectIdDeriviation: 1746506245,
-      projectId: 'angor1qzkfpckm2vnhdvfcwr7vdhwt7ns3rd95gr0age0',
+      projectIdDeriviation: 1345528842,
+      projectId: 'angor1quc59k4kt0nv62xhj72xtqfmzk55cexxmf6pkz7',
       nostrEventId: '0f2d8db8568bd3e12bdab1faa217fffc80459053967eff8bde0a65f14e2b7079',
       addressOnFeeOutput: 'tb1quc59k4kt0nv62xhj72xtqfmzk55cexxmae8lyc',
       txid: '0d28976a42bf7618ad9470cf0202e2eb06d6072e75e139eab012a160b7b480aa',
@@ -261,23 +260,6 @@ describe('AngorTransactionDecoder', () => {
           data.projectIdDeriviation
         );
       });
-
-      it('should throw an error if the retention is greater than 2 in power of 31', () => {
-        jest
-          .spyOn(angorDecoder as any, 'hashToInt')
-          .mockImplementation(() => Math.pow(2, 31) * 2 + 2);
-
-        const keyHash = angorDecoder['getKeyHash'](keyHex);
-        const keyHashInt = angorDecoder['hashToInt'](keyHash);
-
-        expect(() =>
-          angorDecoder['getProjectIdDerivation'](keyHashInt)
-        ).toThrow(
-          new Error(
-            `Retention is too large. The max number is 2^31 (2,147,483,648).`
-          )
-        );
-      });
     });
 
     describe('getProjectId', () => {