New Captcha Package added

packages/captcha/src/crypto.ts

@@ -0,0 +1,55 @@
+const encoder = new TextEncoder();
+
+export function defaultRandomBytes(length: number): Uint8Array {
+  if (!Number.isInteger(length) || length < 1) throw new RangeError("random byte length must be positive");
+  const bytes = new Uint8Array(length);
+  crypto.getRandomValues(bytes);
+  return bytes;
+}
+
+export function bytesToBase64Url(bytes: Uint8Array): string {
+  let binary = "";
+  for (const byte of bytes) binary += String.fromCharCode(byte);
+  return btoa(binary).replace(/\+/g, "-").replace(/\//g, "_").replace(/=+$/g, "");
+}
+
+export function randomId(randomBytes = defaultRandomBytes, length = 24): string {
+  return bytesToBase64Url(randomBytes(length));
+}
+
+function bytesToHex(bytes: Uint8Array): string {
+  let out = "";
+  for (const byte of bytes) out += byte.toString(16).padStart(2, "0");
+  return out;
+}
+
+export async function sha256(value: string): Promise<string> {
+  const digest = await crypto.subtle.digest("SHA-256", encoder.encode(value));
+  return bytesToHex(new Uint8Array(digest));
+}
+
+export async function hmacSha256(secret: string, value: string): Promise<string> {
+  const key = await crypto.subtle.importKey(
+    "raw",
+    encoder.encode(secret),
+    { name: "HMAC", hash: "SHA-256" },
+    false,
+    ["sign"],
+  );
+  const signature = await crypto.subtle.sign("HMAC", key, encoder.encode(value));
+  return bytesToHex(new Uint8Array(signature));
+}
+
+export function constantTimeEqual(left: string, right: string): boolean {
+  if (left.length !== right.length) return false;
+  let difference = 0;
+  for (let index = 0; index < left.length; index++) {
+    difference |= left.charCodeAt(index) ^ right.charCodeAt(index);
+  }
+  return difference === 0;
+}
+
+export async function bindingHash(value: string | undefined): Promise<string | undefined> {
+  if (!value) return undefined;
+  return sha256(value);
+}