diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceAccountManager.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceAccountManager.java
index 3651671609..08ceb824b7 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceAccountManager.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/api/SignalServiceAccountManager.java
@@ -60,6 +60,7 @@ import org.whispersystems.signalservice.internal.contacts.entities.DiscoveryRequ
 import org.whispersystems.signalservice.internal.contacts.entities.DiscoveryResponse;
 import org.whispersystems.signalservice.internal.crypto.ProvisioningCipher;
 import org.whispersystems.signalservice.internal.push.AuthCredentials;
+import org.whispersystems.signalservice.internal.push.CdshAuthResponse;
 import org.whispersystems.signalservice.internal.push.ProfileAvatarData;
 import org.whispersystems.signalservice.internal.push.PushServiceSocket;
 import org.whispersystems.signalservice.internal.push.RemoteAttestationUtil;
@@ -493,8 +494,9 @@ public class SignalServiceAccountManager {
   public Map<String, ACI> getRegisteredUsersWithCdsh(Set<String> e164numbers, String hexPublicKey, String hexCodeHash)
       throws IOException
   {
+    CdshAuthResponse                          auth    = pushServiceSocket.getCdshAuth();
     CdshService                               service = new CdshService(configuration, hexPublicKey, hexCodeHash);
-    Single<ServiceResponse<Map<String, ACI>>> result  = service.getRegisteredUsers(e164numbers);
+    Single<ServiceResponse<Map<String, ACI>>> result  = service.getRegisteredUsers(auth.getUsername(), auth.getPassword(), e164numbers);
 
     ServiceResponse<Map<String, ACI>> response;
     try {
diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/api/services/CdshService.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/api/services/CdshService.java
index 0d129177ce..cbe26e217e 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/api/services/CdshService.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/api/services/CdshService.java
@@ -18,6 +18,7 @@ import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
 import java.io.DataInputStream;
 import java.io.IOException;
+import java.nio.charset.StandardCharsets;
 import java.security.KeyManagementException;
 import java.security.NoSuchAlgorithmException;
 import java.util.Collections;
@@ -82,7 +83,7 @@ public final class CdshService {
     }
   }
 
-  public Single<ServiceResponse<Map<String, ACI>>> getRegisteredUsers(Set<String> e164Numbers) {
+  public Single<ServiceResponse<Map<String, ACI>>> getRegisteredUsers(String username, String password, Set<String> e164Numbers) {
     return Single.create(emitter -> {
       AtomicReference<Stage> stage       = new AtomicReference<>(Stage.WAITING_TO_INITIALIZE);
       List<String>           addressBook = e164Numbers.stream().map(e -> e.substring(1)).collect(Collectors.toList());
@@ -96,7 +97,7 @@ public final class CdshService {
             case WAITING_TO_INITIALIZE:
               enclave.completeHandshake(bytes.toByteArray());
 
-              byte[] request = enclave.establishedSend(buildPlaintextRequest(addressBook));
+              byte[] request = enclave.establishedSend(buildPlaintextRequest(username, password, addressBook));
 
               stage.set(Stage.WAITING_FOR_RESPONSE);
               webSocket.send(ByteString.of(request));
@@ -145,9 +146,11 @@ public final class CdshService {
     });
   }
 
-  private static byte[] buildPlaintextRequest(List<String> addressBook) {
+  private static byte[] buildPlaintextRequest(String username, String password, List<String> addressBook) {
     try (ByteArrayOutputStream outputStream = new ByteArrayOutputStream()) {
       outputStream.write(VERSION);
+      outputStream.write(username.getBytes(StandardCharsets.UTF_8));
+      outputStream.write(password.getBytes(StandardCharsets.UTF_8));
 
       for (String e164 : addressBook) {
         outputStream.write(ByteUtil.longToByteArray(Long.parseLong(e164)));
diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/CdshAuthResponse.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/CdshAuthResponse.java
new file mode 100644
index 0000000000..e51afea3c2
--- /dev/null
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/CdshAuthResponse.java
@@ -0,0 +1,20 @@
+package org.whispersystems.signalservice.internal.push;
+
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+public class CdshAuthResponse {
+
+  @JsonProperty
+  private String username;
+
+  @JsonProperty
+  private String password;
+
+  public String getUsername() {
+    return username;
+  }
+
+  public String getPassword() {
+    return password;
+  }
+}
diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/PushServiceSocket.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/PushServiceSocket.java
index 11b346ecd2..bf7ff260ca 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/PushServiceSocket.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/push/PushServiceSocket.java
@@ -258,6 +258,8 @@ public class PushServiceSocket {
   private static final String BOOST_RECEIPT_CREDENTIALS           = "/v1/subscription/boost/receipt_credentials";
   private static final String BOOST_BADGES                        = "/v1/subscription/boost/badges";
 
+  private static final String CDSH_AUTH = "/v2/directory/auth";
+
   private static final String REPORT_SPAM = "/v1/messages/report/%s/%s";
 
   private static final String SERVER_DELIVERED_TIMESTAMP_HEADER = "X-Signal-Timestamp";
@@ -343,6 +345,11 @@ public class PushServiceSocket {
     return JsonUtil.fromJson(makeServiceRequest(WHO_AM_I, "GET", null), WhoAmIResponse.class);
   }
 
+  public CdshAuthResponse getCdshAuth() throws IOException {
+    String body = makeServiceRequest(CDSH_AUTH, "GET", null);
+    return JsonUtil.fromJsonResponse(body, CdshAuthResponse.class);
+  }
+
   public VerifyAccountResponse verifyAccountCode(String verificationCode, String signalingKey, int registrationId, boolean fetchesMessages,
                                                  String pin, String registrationLock,
                                                  byte[] unidentifiedAccessKey, boolean unrestrictedUnidentifiedAccess,
diff --git a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/util/JsonUtil.java b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/util/JsonUtil.java
index 239043ffc0..0a0a6d31d1 100644
--- a/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/util/JsonUtil.java
+++ b/libsignal/service/src/main/java/org/whispersystems/signalservice/internal/util/JsonUtil.java
@@ -71,7 +71,8 @@ public class JsonUtil {
   }
 
   public static <T> T fromJsonResponse(String body, Class<T> clazz)
-      throws MalformedResponseException {
+      throws MalformedResponseException
+  {
     try {
       return JsonUtil.fromJson(body, clazz);
     } catch (IOException e) {