diff --git a/package.json b/package.json
index f636f387..cfe25c15 100644
--- a/package.json
+++ b/package.json
@@ -109,7 +109,6 @@
     "async-mutex": "^0.4.1",
     "elliptic": "^6.5.4",
     "ethers": "^5.7.2",
-    "js-sha3": "0.9.3",
     "long": "^5.2.3"
   },
   "devDependencies": {
diff --git a/rollup.config.bench.js b/rollup.config.bench.js
index b6642db1..3b465dea 100644
--- a/rollup.config.bench.js
+++ b/rollup.config.bench.js
@@ -12,7 +12,6 @@ const external = [
   'crypto',
   'elliptic',
   'ethers',
-  'js-sha3',
   'long',
 ]
 
diff --git a/rollup.config.js b/rollup.config.js
index ba4454f3..268438aa 100644
--- a/rollup.config.js
+++ b/rollup.config.js
@@ -16,7 +16,6 @@ const external = [
   'crypto',
   'elliptic',
   'ethers',
-  'js-sha3',
   'long',
 ]
 
diff --git a/src/authn/LocalAuthenticator.ts b/src/authn/LocalAuthenticator.ts
index 8180b570..425b7538 100644
--- a/src/authn/LocalAuthenticator.ts
+++ b/src/authn/LocalAuthenticator.ts
@@ -1,11 +1,9 @@
-import sha3 from 'js-sha3'
 import { authn, signature, publicKey } from '@xmtp/proto'
 import AuthData from './AuthData'
 import { PrivateKey } from '../crypto'
 import { hexToBytes } from '../crypto/utils'
 import Token from './Token'
-
-const { keccak256 } = sha3
+import { keccak256 } from 'viem'
 
 export default class LocalAuthenticator {
   private identityKey: PrivateKey
diff --git a/test/authn/Authn.test.ts b/test/authn/Authn.test.ts
index ecf342dc..0e0170fd 100644
--- a/test/authn/Authn.test.ts
+++ b/test/authn/Authn.test.ts
@@ -1,4 +1,3 @@
-import sha3 from 'js-sha3'
 import Long from 'long'
 import { PrivateKey, PrivateKeyBundleV1, Signature } from '../../src/crypto'
 import Authenticator from '../../src/authn/LocalAuthenticator'
@@ -7,8 +6,7 @@ import { hexToBytes } from '../../src/crypto/utils'
 import { newWallet, sleep } from '../helpers'
 import { Wallet } from 'ethers'
 import AuthCache from '../../src/authn/AuthCache'
-
-const { keccak256 } = sha3
+import { keccak256 } from 'viem'
 
 describe('authn', () => {
   let authenticator: Authenticator
diff --git a/yarn.lock b/yarn.lock
index 8454e638..0bffe4bf 100644
--- a/yarn.lock
+++ b/yarn.lock
@@ -2571,7 +2571,6 @@ __metadata:
     ethers: "npm:^5.7.2"
     happy-dom: "npm:^13.6.2"
     husky: "npm:^7.0.4"
-    js-sha3: "npm:0.9.3"
     long: "npm:^5.2.3"
     prettier: "npm:^3.2.5"
     prettier-plugin-packagejson: "npm:^2.4.12"
@@ -6289,13 +6288,6 @@ __metadata:
   languageName: node
   linkType: hard
 
-"js-sha3@npm:0.9.3":
-  version: 0.9.3
-  resolution: "js-sha3@npm:0.9.3"
-  checksum: 10/8daacb93b18609a0dc081f2f6199b80a96df36f9975b4b9c7476ae92822e07100b9e1969fc76f4b58e703cd6175f0de7656a99cbb2335cfb554c66f988fbead5
-  languageName: node
-  linkType: hard
-
 "js-tokens@npm:^4.0.0":
   version: 4.0.0
   resolution: "js-tokens@npm:4.0.0"