🚧 Added Proof of Work on image-upload and more

frontend/src/lib/hashcash.ts

@@ -0,0 +1,47 @@
+import { DateTime } from 'luxon';
+
+const gen_salt = (l: number): string => {
+	const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
+	const charLength = chars.length;
+	let result = '';
+	for (let i = 0; i < l; i++) {
+		result += chars.charAt(Math.floor(Math.random() * charLength));
+	}
+	return result;
+};
+
+export const mint = async (
+	resource: string,
+	bits = 19,
+	now = null,
+	ext = '',
+	saltchars = 8,
+	stamp_seconds = false
+): Promise<string> => {
+	const ver = '1';
+	let ts;
+	if (stamp_seconds) {
+		ts = DateTime.now().toFormat('yyMMddHHmmss');
+	} else {
+		ts = DateTime.now().toFormat('yyMMdd');
+	}
+	const hex_digits = Math.ceil(bits / 4);
+	const zeros = '0'.repeat(hex_digits);
+	const salt = gen_salt(saltchars);
+	const challenge = `${ver}:${bits}:${ts}:${resource}:${ext}:${salt}`;
+	let digest: string;
+	let counter = 0;
+	let result: string;
+	while (true) {
+		const data = new TextEncoder().encode(`${challenge}:${counter.toString(16)}`);
+		const hashBuffer = await crypto.subtle.digest('SHA-1', data);
+		const hashArray = Array.from(new Uint8Array(hashBuffer));
+		const digest = hashArray.map((b) => b.toString(16).padStart(2, '0')).join('');
+		if (digest.slice(0, hex_digits) == zeros) {
+			result = counter.toString(16);
+			break;
+		}
+		counter += 1;
+	}
+	return `${challenge}:${result}`;
+};