fix a potential collision

IGA.ts

@@ -98,6 +98,17 @@ function hex2bin(hex: string): string {
     }
     return bin
 }
+function xor(a: string, b: string): string {
+    let out = ""
+    for (let i = 0; i < a.length; i++) {
+        if (a[i] == b[i]) {
+            out += "0"
+        } else {
+            out += "1"
+        }
+    }
+    return out
+}
 
 function checksum(input: string) {
     let state: string[] = []
@@ -216,18 +227,13 @@ function hash(input: string, salt: number = 0, len: number = 32, seed?: number):
             dataBins[i] += fixbin(dec2bin(blocks[i][0][ii]), 16)
         }
     }
-    let hashes: string[] = []
-    for (let i = 0; i < dataBins.length; i++) {
-        let hsh = bin2hex(pBin+dataBins[i])
-        const crc = checksum(hsh)
-        hsh += bin2hex(crc)
-        hashes.push(hsh)
-    }
-    if (hashes.length == 1) {
-        return hashes[0]
-    } else {
-        return hash(hashes.join(""), salt, len, padding.seed)
+    while (dataBins.length > 1) {
+        dataBins[0] = xor(dataBins[0], dataBins[1])
+        dataBins.splice(1, 1)
     }
+    const crc = checksum(dataBins[0])
+    const hash = bin2hex(pBin + dataBins[0] + crc)
+    return hash
 }
 
 function verifyHash(input: string, inHash: string, salt: number = 0, len: number = 32): verifyOut {