feat: 초기 프로젝트 설정 및 룰.md 파일 추가

api.hyungi.net/node_modules/@simplewebauthn/server/esm/helpers/convertCOSEtoPKCS.js

@@ -0,0 +1,21 @@
+import { isoCBOR, isoUint8Array } from './iso/index.js';
+import { COSEKEYS } from './cose.js';
+/**
+ * Takes COSE-encoded public key and converts it to PKCS key
+ */
+export function convertCOSEtoPKCS(cosePublicKey) {
+    // This is a little sloppy, I'm using COSEPublicKeyEC2 since it could have both x and y, but when
+    // there's no y it means it's probably better typed as COSEPublicKeyOKP. I'll leave this for now
+    // and revisit it later if it ever becomes an actual problem.
+    const struct = isoCBOR.decodeFirst(cosePublicKey);
+    const tag = Uint8Array.from([0x04]);
+    const x = struct.get(COSEKEYS.x);
+    const y = struct.get(COSEKEYS.y);
+    if (!x) {
+        throw new Error('COSE public key was missing x');
+    }
+    if (y) {
+        return isoUint8Array.concat([tag, x, y]);
+    }
+    return isoUint8Array.concat([tag, x]);
+}