updates

Unibw 2023/crypto/T800 - I'm Back/utils.js

@@ -0,0 +1,124 @@
+"use strict";
+
+async function postJSON(url, data) {
+	const response = await fetch(url, {
+		method: 'POST',
+		headers: {
+			'Content-Type': 'application/json'
+		},
+		body: JSON.stringify(data),
+	});
+	if (!response.ok) {
+		if (response.statusText) {
+			throw new Error(response.statusText);
+		} else {
+			throw new Error("Something went wrong");
+		}
+	}
+	return response.json();
+}
+
+async function getJSON(url) {
+	const response = await fetch(url);
+	if (!response.ok) {
+		if (response.statusText) {
+			throw new Error(response.statusText);
+		} else {
+			throw new Error("Something went wrong");
+		}
+	}
+	return response.json();
+}
+
+function verifySig(pubkey, signature, data) {
+	return window.crypto.subtle.verify(
+		{
+			name: "ECDSA",
+			hash: { name: "SHA-256" },
+		},
+		pubkey,
+		signature,
+		data,
+	);
+}
+
+function signData(privkey, data) {
+	return window.crypto.subtle.sign(
+		{
+			name: "ECDSA",
+			hash: { name: "SHA-256" },
+		},
+		privkey,
+		data,
+	);
+}
+
+function ab2str(buf) {
+	let binary = '';
+	const bytes = new Uint8Array(buf);
+	for (let i = 0, len = bytes.byteLength; i < len; i++) {
+		binary += String.fromCharCode(bytes[i]);
+	}
+	return binary;
+}
+
+// PEM key import code from:
+// https://developer.mozilla.org/en-US/docs/Web/API/SubtleCrypto/importKey#pkcs_8_import
+
+function str2ab(str) {
+	const buf = new ArrayBuffer(str.length);
+	const bufView = new Uint8Array(buf);
+	for (let i = 0, len = str.length; i < len; i++) {
+		bufView[i] = str.charCodeAt(i);
+	}
+	return buf;
+}
+
+function importPrivateKey(pem) {
+	// fetch the part of the PEM string between header and footer
+	const pemHeader = "-----BEGIN PRIVATE KEY-----";
+	const pemFooter = "-----END PRIVATE KEY-----";
+	if (pem.length < pemHeader.length + pemFooter.length + 90 ||
+		  pem.indexOf(pemHeader) < 0 ||
+		  pem.indexOf(pemFooter) < 0) {
+		throw new Error("Invalid PEM key format");
+	}
+	const pemContents = pem.substring(
+		pem.indexOf(pemHeader) + pemHeader.length,
+		pem.indexOf(pemFooter),
+	);
+	// base64 decode the string to get the binary data
+	const binaryDerString = window.atob(pemContents);
+	// convert from a binary string to an ArrayBuffer
+	const binaryDer = str2ab(binaryDerString);
+
+	return window.crypto.subtle.importKey(
+		"pkcs8",
+		binaryDer,
+		{
+			name: "ECDSA",
+			namedCurve: "P-256",
+		},
+		false,
+		["sign"],
+	);
+}
+
+function adminPublicKey() {
+	const pemContents = "MFkwEwYHKoZIzj0CAQYIKoZIzj0DAQcDQgAEG4nMe1/gySwCCGQxHL4nlwmpcOYllW1PDH0nQhoNYhGHK/UBtfgUKG9u/XjcWfEYFY2cvZWGrPyHzhzxVnV8bA==";
+	// base64 decode the string to get the binary data
+	const binaryDerString = window.atob(pemContents);
+	// convert from a binary string to an ArrayBuffer
+	const binaryDer = str2ab(binaryDerString);
+
+	return window.crypto.subtle.importKey(
+		"spki",
+		binaryDer,
+		{
+			name: "ECDSA",
+			namedCurve: "P-256",
+		},
+		false,
+		["verify"],
+	);
+}