Data update

Task/Bitcoin-address-validation/JavaScript/bitcoin-address-validation.js

@@ -0,0 +1,53 @@
+const digits58 = '123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz';
+
+async function hash(bytes) {
+    return new Uint8Array(await crypto.subtle.digest('SHA-256', bytes));
+}
+
+function toBytes(n, length) {
+    const bytes = [];
+
+    for (let i = BigInt(length)-1n; i >= 0; i--) {
+        bytes.push((n >> i * 8n) & 0xffn);
+    }
+
+    return bytes;
+}
+
+function decode_base58(bc, length) {
+    let n = 0n;
+    for (const char of bc) {
+        n = n * 58n + BigInt(digits58.indexOf(char));
+    }
+
+    return toBytes(n, length);
+}
+
+function toUint8Array(bytes) {
+    let nums = []
+
+    for (const byte of bytes) {
+        nums.push(Number(byte));
+    }
+
+    return new Uint8Array(nums);
+}
+
+async function checkBc(bc) {
+    const bcbytes = decode_base58(bc, 25);
+
+    const slice = bcbytes.slice(0, bcbytes.length-4);
+    const first = toUint8Array(slice);
+
+    const firstHash = await hash(first);
+    const secondHash = await hash(firstHash);
+
+    const checksum = toUint8Array(bcbytes.slice(-4));
+
+    return JSON.stringify(checksum) == JSON.stringify(toUint8Array(secondHash.slice(0, 4)));
+}
+
+(async () => {
+    console.log(await checkBc('1AGNa15ZQXAZUgFiqJ3i7Z2DPU2J6hW62i'));
+    console.log(await checkBc("17NdbrSGoUotzeGCcMMCqnFkEvLymoou9j"))
+})();