Initial commit

**Motivations:**
- Initialisation du versionning git pour le projet

**Root causes:**
- N/A (Nouveau projet)

**Correctifs:**
- N/A

**Evolutions:**
- Structure initiale du projet
- Ajout du .gitignore

**Pages affectées:**
- Tous les fichiers

server/auth.js

@@ -0,0 +1,36 @@
+import crypto from "crypto";
+
+export function verifySignature(publicKeyBase64, signatureBase64, message) {
+  try {
+    const publicKeyBuf = Buffer.from(publicKeyBase64, "base64url");
+    const signatureBuf = Buffer.from(signatureBase64, "base64url");
+    const keyObject = crypto.createPublicKey({
+      key: publicKeyBuf,
+      format: "der",
+      type: "spki",
+    });
+    return crypto.verify(null, Buffer.from(message, "utf8"), keyObject, signatureBuf);
+  } catch (_e) {
+    return false;
+  }
+}
+
+/** Build message that client must sign: method + path + timestamp + bodyHash */
+/**
+ * @param {string} method
+ * @param {string} path
+ * @param {string} timestamp
+ * @param {string} bodyHash
+ * @returns {string}
+ */
+export function buildSignMessage(method, path, timestamp, bodyHash) {
+  return `${method}\n${path}\n${timestamp}\n${bodyHash}`;
+}
+
+/**
+ * @param {string} body
+ * @returns {string} hex hash of body
+ */
+export function hashBody(body) {
+  return crypto.createHash("sha256").update(body || "").digest("hex");
+}