diff --git a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/KeysController.java b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/KeysController.java
index 41f949082..baa9382e4 100644
--- a/service/src/main/java/org/whispersystems/textsecuregcm/controllers/KeysController.java
+++ b/service/src/main/java/org/whispersystems/textsecuregcm/controllers/KeysController.java
@@ -52,6 +52,7 @@ import org.whispersystems.textsecuregcm.entities.PreKeyCount;
 import org.whispersystems.textsecuregcm.entities.PreKeyResponse;
 import org.whispersystems.textsecuregcm.entities.PreKeyResponseItem;
 import org.whispersystems.textsecuregcm.entities.PreKeyState;
+import org.whispersystems.textsecuregcm.experiment.Experiment;
 import org.whispersystems.textsecuregcm.limits.RateLimiters;
 import org.whispersystems.textsecuregcm.metrics.UserAgentTagUtil;
 import org.whispersystems.textsecuregcm.storage.Account;
@@ -64,9 +65,10 @@ import org.whispersystems.textsecuregcm.storage.KeysManager;
 @Tag(name = "Keys")
 public class KeysController {
 
-  private final RateLimiters                rateLimiters;
+  private final RateLimiters rateLimiters;
   private final KeysManager keys;
-  private final AccountsManager             accounts;
+  private final AccountsManager accounts;
+  private final Experiment compareSignedEcPreKeysExperiment = new Experiment("compareSignedEcPreKeys");
 
   private static final String IDENTITY_KEY_CHANGE_COUNTER_NAME = name(KeysController.class, "identityKeyChange");
   private static final String IDENTITY_KEY_CHANGE_FORBIDDEN_COUNTER_NAME = name(KeysController.class, "identityKeyChangeForbidden");
@@ -224,6 +226,9 @@ public class KeysController {
       ECPreKey unsignedECPreKey = keys.takeEC(identifier, device.getId()).orElse(null);
       KEMSignedPreKey pqPreKey = returnPqKey ? keys.takePQ(identifier, device.getId()).orElse(null) : null;
 
+      compareSignedEcPreKeysExperiment.compareFutureResult(Optional.ofNullable(signedECPreKey),
+          keys.getEcSignedPreKey(identifier, device.getId()));
+
       if (signedECPreKey != null || unsignedECPreKey != null || pqPreKey != null) {
         final int registrationId = usePhoneNumberIdentity ?
             device.getPhoneNumberIdentityRegistrationId().orElse(device.getRegistrationId()) :
diff --git a/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/KeysControllerTest.java b/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/KeysControllerTest.java
index 9b099758c..ad94fddc7 100644
--- a/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/KeysControllerTest.java
+++ b/service/src/test/java/org/whispersystems/textsecuregcm/tests/controllers/KeysControllerTest.java
@@ -33,6 +33,7 @@ import java.util.List;
 import java.util.Optional;
 import java.util.OptionalInt;
 import java.util.UUID;
+import java.util.concurrent.CompletableFuture;
 import javax.ws.rs.client.Entity;
 import javax.ws.rs.core.MediaType;
 import javax.ws.rs.core.Response;
@@ -221,6 +222,8 @@ class KeysControllerTest {
 
     when(rateLimiters.getPreKeysLimiter()).thenReturn(rateLimiter);
 
+    when(KEYS.getEcSignedPreKey(any(), anyLong())).thenReturn(CompletableFuture.completedFuture(Optional.empty()));
+
     when(KEYS.takeEC(EXISTS_UUID, 1)).thenReturn(Optional.of(SAMPLE_KEY));
     when(KEYS.takePQ(EXISTS_UUID, 1)).thenReturn(Optional.of(SAMPLE_PQ_KEY));
     when(KEYS.takeEC(EXISTS_PNI, 1)).thenReturn(Optional.of(SAMPLE_KEY_PNI));
@@ -325,6 +328,7 @@ class KeysControllerTest {
     assertEquals(existsAccount.getDevice(1).get().getSignedPreKey(), result.getDevice(1).getSignedPreKey());
 
     verify(KEYS).takeEC(EXISTS_UUID, 1);
+    verify(KEYS).getEcSignedPreKey(EXISTS_UUID, 1);
     verifyNoMoreInteractions(KEYS);
   }
 
@@ -348,6 +352,7 @@ class KeysControllerTest {
 
     verify(KEYS).takeEC(EXISTS_UUID, 1);
     verify(KEYS).takePQ(EXISTS_UUID, 1);
+    verify(KEYS).getEcSignedPreKey(EXISTS_UUID, 1);
     verifyNoMoreInteractions(KEYS);
   }
 
@@ -369,6 +374,7 @@ class KeysControllerTest {
 
     verify(KEYS).takeEC(EXISTS_UUID, 1);
     verify(KEYS).takePQ(EXISTS_UUID, 1);
+    verify(KEYS).getEcSignedPreKey(EXISTS_UUID, 1);
     verifyNoMoreInteractions(KEYS);
   }
 
@@ -388,6 +394,7 @@ class KeysControllerTest {
     assertEquals(existsAccount.getDevice(1).get().getPhoneNumberIdentitySignedPreKey(), result.getDevice(1).getSignedPreKey());
 
     verify(KEYS).takeEC(EXISTS_PNI, 1);
+    verify(KEYS).getEcSignedPreKey(EXISTS_PNI, 1);
     verifyNoMoreInteractions(KEYS);
   }
 
@@ -409,6 +416,7 @@ class KeysControllerTest {
 
     verify(KEYS).takeEC(EXISTS_PNI, 1);
     verify(KEYS).takePQ(EXISTS_PNI, 1);
+    verify(KEYS).getEcSignedPreKey(EXISTS_PNI, 1);
     verifyNoMoreInteractions(KEYS);
   }
 
@@ -430,6 +438,7 @@ class KeysControllerTest {
     assertEquals(existsAccount.getDevice(1).get().getPhoneNumberIdentitySignedPreKey(), result.getDevice(1).getSignedPreKey());
 
     verify(KEYS).takeEC(EXISTS_PNI, 1);
+    verify(KEYS).getEcSignedPreKey(EXISTS_PNI, 1);
     verifyNoMoreInteractions(KEYS);
   }
 
@@ -465,6 +474,7 @@ class KeysControllerTest {
 
     verify(KEYS).takeEC(EXISTS_UUID, 1);
     verify(KEYS).takePQ(EXISTS_UUID, 1);
+    verify(KEYS).getEcSignedPreKey(EXISTS_UUID, 1);
     verifyNoMoreInteractions(KEYS);
   }
 
@@ -557,6 +567,9 @@ class KeysControllerTest {
     verify(KEYS).takeEC(EXISTS_UUID, 1);
     verify(KEYS).takeEC(EXISTS_UUID, 2);
     verify(KEYS).takeEC(EXISTS_UUID, 4);
+    verify(KEYS).getEcSignedPreKey(EXISTS_UUID, 1);
+    verify(KEYS).getEcSignedPreKey(EXISTS_UUID, 2);
+    verify(KEYS).getEcSignedPreKey(EXISTS_UUID, 4);
     verifyNoMoreInteractions(KEYS);
   }
 
@@ -622,6 +635,9 @@ class KeysControllerTest {
     verify(KEYS).takePQ(EXISTS_UUID, 2);
     verify(KEYS).takeEC(EXISTS_UUID, 4);
     verify(KEYS).takePQ(EXISTS_UUID, 4);
+    verify(KEYS).getEcSignedPreKey(EXISTS_UUID, 1);
+    verify(KEYS).getEcSignedPreKey(EXISTS_UUID, 2);
+    verify(KEYS).getEcSignedPreKey(EXISTS_UUID, 4);
     verifyNoMoreInteractions(KEYS);
   }