diff --git a/backend/src/db.js b/backend/src/db.js
index 8d0cad1..722114a 100644
--- a/backend/src/db.js
+++ b/backend/src/db.js
@@ -4,9 +4,11 @@ const dataDir = process.env.LEVEL_DATA_DIR || 'data';
 
 module.exports = {
   forum: new Level(`${dataDir}/forum`, { valueEncoding: 'json' }),
-  authorAddresses: new Level(`${dataDir}/authorAddresses`, { valueEncoding: 'utf8' }),
-  authorPrivKeys: new Level(`${dataDir}/authorPrivKeys`, { valueEncoding: 'utf8' }),
+  authorAddresses: new Level(`${dataDir}/authorAddresses`),
+  authorPrivKeys: new Level(`${dataDir}/authorPrivKeys`),
   appState: new Level(`${dataDir}/appState`, { valueEncoding: 'json' }),
-  proposalEventIds: new Level(`${dataDir}/proposalEventIds`, { keyEncoding: 'json', valueEncoding: 'utf8' }),
-  referendumEventIds: new Level(`${dataDir}/referendumEventIds`, { keyEncoding: 'json', valueEncoding: 'utf8' }),
+  proposalEventIds: new Level(`${dataDir}/proposalEventIds`, { keyEncoding: 'json' }),
+  referendumEventIds: new Level(`${dataDir}/referendumEventIds`, { keyEncoding: 'json' }),
+  matrixUserToAuthorAddress: new Level(`${dataDir}/matrixUserToAuthorAddress`),
+  authorAddressToMatrixUser: new Level(`${dataDir}/authorAddressToMatrixUser`),
 };
diff --git a/backend/src/matrix.js b/backend/src/matrix.js
index 5624d76..c8813cb 100644
--- a/backend/src/matrix.js
+++ b/backend/src/matrix.js
@@ -5,8 +5,14 @@ const {
   SimpleFsStorageProvider,
 } = require('matrix-bot-sdk');
 const fastq = require('fastq');
+const { recoverPersonalSignature } = require('@metamask/eth-sig-util');
 
-const { appState, proposalEventIds } = require('./db');
+const {
+  appState,
+  proposalEventIds,
+  matrixUserToAuthorAddress,
+  authorAddressToMatrixUser,
+} = require('./db');
 
 const {
   MATRIX_HOMESERVER_URL,
@@ -111,9 +117,19 @@ const start = async () => {
   };
 
   const handleRegisterIdentity = async (roomId, event) => {
-    // const { message, signature } = event.content;
+    const { message, signature } = event.content;
     console.log('Received request to register identity');
-    await client.replyNotice(roomId, event, 'Received request to register identity');
+    let account;
+    try {
+      account = recoverPersonalSignature({ data: message, signature });
+    } catch (e) {
+      console.log('error: failed to recover signature:', e.message);
+    }
+    if (account) {
+      await matrixUserToAuthorAddress.put(event.sender, account);
+      await authorAddressToMatrixUser.put(account, event.sender);
+    }
+    await client.sendNotice(roomId, `Registered matrix user ${event.sender} to author address ${account}`);
   };
 
   // Before we start the bot, register our command handler