prove identity using wot.computeFingerprint()

This replaces the old `crypto.getFingerprint()` shown in user profiles.
The new method will create a hash of _all_ relevant public keys for a given user.
Also it is based on JWK Thumbprints, which are more standardized and are encoding-agnostic

frontend/src/common/crypto.ts

@@ -466,18 +466,6 @@ export async function asPublicKey(publicKey: CryptoKey | BufferSource, keyDesign
   }
 }
 
-export async function getFingerprint(key: string | undefined) {
-  if (key) {
-    const encodedKey = new TextEncoder().encode(key);
-    const hashBuffer = await crypto.subtle.digest('SHA-256', encodedKey);
-    const hashArray = Array.from(new Uint8Array(hashBuffer));
-    const hashHex = hashArray
-      .map((b) => b.toString(16).padStart(2, '0').toUpperCase())
-      .join('');
-    return hashHex;
-  }
-}
-
 /**
  * Computes the JWK Thumbprint (RFC 7638) using SHA-256.
  * @param key A key to compute the thumbprint for

frontend/src/common/wot.ts

@@ -1,6 +1,6 @@
 import { base64 } from 'rfc4648';
 import backend, { TrustDto, UserDto } from './backend';
-import { UserKeys, asPublicKey } from './crypto';
+import { UserKeys, asPublicKey, getJwkThumbprint } from './crypto';
 import { JWT, JWTHeader } from './jwt';
 import userdata from './userdata';
 
@@ -75,4 +75,22 @@ async function verifyRescursive(signatureChain: string[], signerPublicKey: Crypt
   }
 }
 
-export default { sign, verify };
+async function computeFingerprint(user: UserDto) {
+  if (!user.ecdhPublicKey || !user.ecdsaPublicKey) {
+    throw new Error('User has no public keys');
+  }
+  const ecdhPublicKey = await asPublicKey(base64.parse(user.ecdhPublicKey), UserKeys.ECDH_KEY_DESIGNATION);
+  const ecdsaPublicKey = await asPublicKey(base64.parse(user.ecdsaPublicKey), UserKeys.ECDSA_KEY_DESIGNATION, UserKeys.ECDSA_PUB_KEY_USAGES);
+  const concatenatedThumbprints = new Uint8Array([
+    ...await getJwkThumbprint(ecdhPublicKey),
+    ...await getJwkThumbprint(ecdsaPublicKey)
+  ]);
+  const digest = await crypto.subtle.digest('SHA-256', concatenatedThumbprints);
+  const digestBytes = Array.from(new Uint8Array(digest));
+  const digestHexStr = digestBytes
+    .map((b) => b.toString(16).padStart(2, '0').toUpperCase())
+    .join('');
+  return digestHexStr;
+}
+
+export default { sign, verify, computeFingerprint };

frontend/src/components/GrantPermissionDialog.vue

@@ -72,7 +72,8 @@ import { base64 } from 'rfc4648';
 import { onMounted, ref } from 'vue';
 import { useI18n } from 'vue-i18n';
 import backend, { AccessGrant, ConflictError, NotFoundError, UserDto, VaultDto } from '../common/backend';
-import { VaultKeys, getFingerprint } from '../common/crypto';
+import { VaultKeys } from '../common/crypto';
+import wot from '../common/wot';
 
 const { t } = useI18n({ useScope: 'global' });
 
@@ -101,7 +102,7 @@ onMounted(fetchData);
 
 async function fetchData() {
   for (const user of props.users) {
-    userKeyFingerprints.value.set(user.id, await getFingerprint(user.ecdhPublicKey));
+    userKeyFingerprints.value.set(user.id, await wot.computeFingerprint(user));
   }
 }
 

frontend/src/components/UserProfile.vue

@@ -54,7 +54,7 @@
       <div class="grid grid-cols-1 gap-8 lg:col-span-3">
         <ManageSetupCode />
         <DeviceList />
-        <UserkeyFingerprint :user-public-key="me.ecdhPublicKey"/>
+        <UserkeyFingerprint :user="me"/>
       </div>
     </div>
   </div>

frontend/src/components/UserkeyFingerprint.vue

@@ -20,20 +20,22 @@
 <script setup lang="ts">
 import { onMounted, ref } from 'vue';
 import { useI18n } from 'vue-i18n';
-import { getFingerprint } from '../common/crypto';
+import { UserDto } from '../common/backend';
+import wot from '../common/wot';
 
 const { t } = useI18n({ useScope: 'global' });
 
 const keyFingerprint = ref<string | undefined>();
 
 const props = defineProps<{
-  userPublicKey?: string
+  user: UserDto
 }>();
 
 onMounted(fetchData);
 
 async function fetchData() {
-  keyFingerprint.value = await getFingerprint(props.userPublicKey).then((key) => key?.replace(/.{8}/g, "$&" + " "))
+  const fingerprint = await wot.computeFingerprint(props.user);
+  keyFingerprint.value = fingerprint?.replace(/.{8}/g, "$&" + " ").trim(); // Add space after every 8 characters
 }
 
 </script>