diff --git a/src/identity.ts b/src/identity.ts
index 112a12d..8a11b82 100644
--- a/src/identity.ts
+++ b/src/identity.ts
@@ -234,6 +234,30 @@ export class Contacts {
     this.contacts[hash].push(contact);
   }
 
+  public hasContact(nameOrHash: string | NodeHash): boolean {
+    if (typeof nameOrHash === "string") {
+      return Object.values(this.contacts)
+        .flat()
+        .some((contact) => contact.name.toLowerCase() === nameOrHash.toLowerCase());
+    } else {
+      const hash = parseNodeHash(nameOrHash) as number;
+      return (this.contacts[hash] || []).length > 0;
+    }
+  }
+
+  public getContactByName(name: string): Contact | null {
+    const contact = Object.values(this.contacts)
+      .flat()
+      .find((contact) => contact.name.toLowerCase() === name.toLowerCase());
+    return contact || null;
+  }
+
+  public getContacts(): Contact[] {
+    const contacts = Object.values(this.contacts).flat();
+    contacts.sort((a, b) => a.name.localeCompare(b.name));
+    return contacts;
+  }
+
   public decrypt(
     src: NodeHash | PublicKey,
     dst: NodeHash,
@@ -302,13 +326,54 @@ export class Contacts {
   }
 
   public addGroup(group: Group) {
+    // Remove any group with the same name (regardless of hash), the hash may
+    // have changed if the secret was changed, but the name is what identifies
+    // the group to the user.
+    for (const key of Object.keys(this.groups)) {
+      const hash = Number(key);
+      this.groups[hash] = this.groups[hash].filter((g) => g.name.toLowerCase() !== group.name.toLowerCase());
+      if (this.groups[hash].length === 0) {
+        delete this.groups[hash];
+      }
+    }
+
     const hash = group.hash() as number;
+
     if (!this.groups[hash]) {
       this.groups[hash] = [];
     }
+
     this.groups[hash].push(group);
   }
 
+  public hasGroup(nameOrHash: string | NodeHash): boolean {
+    if (typeof nameOrHash === "string") {
+      return Object.values(this.groups)
+        .flat()
+        .some((group) => group.name.toLowerCase() === nameOrHash.toLowerCase());
+    } else {
+      const hash = parseNodeHash(nameOrHash) as number;
+      return (this.groups[hash] || []).length > 0;
+    }
+  }
+
+  public getGroupByName(name: string): Group | null {
+    const group = Object.values(this.groups)
+      .flat()
+      .find((group) => group.name.toLowerCase() === name.toLowerCase());
+    return group || null;
+  }
+
+  public getGroups(): Group[] {
+    const groups = Object.values(this.groups).flat();
+    groups.sort((a, b) => {
+      if (a.name === "Public") return -1;
+      if (b.name === "Public") return 1;
+      return a.name.localeCompare(b.name);
+    });
+    return groups;
+  }
+
   public decryptGroupText(
     channelHash: NodeHash,
     hmac: Uint8Array,