diff --git a/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.h b/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.h
--- a/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.h
+++ b/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.h
@@ -24,6 +24,7 @@
       const std::string &callingProcessName);
 
 public:
+  const static int olmEncryptedTypeMessage;
   static void
   initializeNotificationsCryptoAccount(const std::string &callingProcessName);
   static void clearSensitiveData();
diff --git a/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.cpp b/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.cpp
--- a/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.cpp
+++ b/native/cpp/CommonCpp/Notifications/BackgroundDataStorage/NotificationsCryptoModule.cpp
@@ -23,6 +23,7 @@
     "keyserverHostedNotificationsID";
 const std::string NotificationsCryptoModule::initialEncryptedMessageContent =
     "{\"type\": \"init\"}";
+const int NotificationsCryptoModule::olmEncryptedTypeMessage = 1;
 
 crypto::CryptoModule NotificationsCryptoModule::deserializeCryptoModule(
     const std::string &path,
diff --git a/native/ios/Comm.xcodeproj/project.pbxproj b/native/ios/Comm.xcodeproj/project.pbxproj
--- a/native/ios/Comm.xcodeproj/project.pbxproj
+++ b/native/ios/Comm.xcodeproj/project.pbxproj
@@ -58,6 +58,7 @@
 		CB38B48628771CDD00171182 /* TemporaryMessageStorage.mm in Sources */ = {isa = PBXBuildFile; fileRef = CB38B47F28771A3B00171182 /* TemporaryMessageStorage.mm */; };
 		CB38B48728771CE500171182 /* TemporaryMessageStorage.mm in Sources */ = {isa = PBXBuildFile; fileRef = CB38B47F28771A3B00171182 /* TemporaryMessageStorage.mm */; };
 		CB38F2B1286C6C870010535C /* MessageOperationsUtilities.cpp in Sources */ = {isa = PBXBuildFile; fileRef = CB38F2AF286C6C870010535C /* MessageOperationsUtilities.cpp */; };
+		CB3C0A3B2A125C8F009BD4DA /* NotificationsCryptoModule.cpp in Sources */ = {isa = PBXBuildFile; fileRef = CB24361729A39A2500FEC4E1 /* NotificationsCryptoModule.cpp */; };
 		CB3C621127CE4A320054F24C /* Logger.mm in Sources */ = {isa = PBXBuildFile; fileRef = 71CA4A63262DA8E500835C89 /* Logger.mm */; };
 		CB3C621227CE65030054F24C /* CommSecureStoreIOSWrapper.mm in Sources */ = {isa = PBXBuildFile; fileRef = 71142A7626C2650A0039DCBD /* CommSecureStoreIOSWrapper.mm */; };
 		CB4821A927CFB153001AB7E1 /* WorkerThread.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 718DE99C2653D41C00365824 /* WorkerThread.cpp */; };
@@ -1028,6 +1029,7 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				CB3C0A3B2A125C8F009BD4DA /* NotificationsCryptoModule.cpp in Sources */,
 				CB90951F29534B32002F2A7F /* CommSecureStore.mm in Sources */,
 				CB38B48728771CE500171182 /* TemporaryMessageStorage.mm in Sources */,
 				CB38B48528771CB800171182 /* EncryptedFileUtils.mm in Sources */,
diff --git a/native/ios/NotificationService/NotificationService.mm b/native/ios/NotificationService/NotificationService.mm
--- a/native/ios/NotificationService/NotificationService.mm
+++ b/native/ios/NotificationService/NotificationService.mm
@@ -1,8 +1,13 @@
 #import "NotificationService.h"
 #import "Logger.h"
+#import "NotificationsCryptoModule.h"
 #import "TemporaryMessageStorage.h"
 
 NSString *const backgroundNotificationTypeKey = @"backgroundNotifType";
+NSString *const messageInfosKey = @"messageInfos";
+NSString *const encryptedPayloadKey = @"encryptedPayload";
+NSString *const encryptionFailureKey = @"encryptionFailure";
+const std::string callingProcessName = "NSE";
 // The context for this constant can be found here:
 // https://linear.app/comm/issue/ENG-3074#comment-bd2f5e28
 int64_t const notificationRemovalDelay = (int64_t)(0.1 * NSEC_PER_SEC);
@@ -26,6 +31,24 @@
   self.contentHandler = contentHandler;
   self.bestAttemptContent = [request.content mutableCopy];
 
+  if ([self shouldBeDecrypted:self.bestAttemptContent.userInfo]) {
+    @try {
+      [self decryptBestAttemptContent];
+    } @catch (NSException *e) {
+      comm::Logger::log(
+          "NSE: Received exception: " + std::string([e.name UTF8String]) +
+          " with reason: " + std::string([e.reason UTF8String]) +
+          " during notification decryption");
+      self.contentHandler([[UNNotificationContent alloc] init]);
+      return;
+    }
+  } else if ([self shouldAlertUnencryptedNotification:self.bestAttemptContent
+                                                          .userInfo]) {
+    // In future this will be replaced by notification content
+    // modification for DEV environment and staff members
+    comm::Logger::log("NSE: Received erroneously unencrypted notitication.");
+  }
+
   [self persistMessagePayload:self.bestAttemptContent.userInfo];
   // Message payload persistence is a higher priority task, so it has
   // to happen prior to potential notification center clearing.
@@ -52,6 +75,16 @@
     // It is an extremely unlikely to happen.
     comm::Logger::log("NSE: Exceeded time limit to rescind a notification.");
     self.contentHandler([[UNNotificationContent alloc] init]);
+    return;
+  }
+  if ([self shouldBeDecrypted:self.bestAttemptContent.userInfo] &&
+      !self.bestAttemptContent.userInfo[@"succesfullyDecrypted"]) {
+    // If we get to this place it means we were unable to
+    // decrypt encrypted notification content in time
+    // given to NSE to process notification.
+    comm::Logger::log("NSE: Exceeded time limit to decrypt a notification.");
+    self.contentHandler([[UNNotificationContent alloc] init]);
+    return;
   }
   self.contentHandler(self.bestAttemptContent);
 }
@@ -85,10 +118,10 @@
 }
 
 - (void)persistMessagePayload:(NSDictionary *)payload {
-  if (payload[@"messageInfos"]) {
+  if (payload[messageInfosKey]) {
     TemporaryMessageStorage *temporaryStorage =
         [[TemporaryMessageStorage alloc] init];
-    [temporaryStorage writeMessage:payload[@"messageInfos"]];
+    [temporaryStorage writeMessage:payload[messageInfosKey]];
     return;
   }
 
@@ -131,4 +164,85 @@
       TRUE);
 }
 
+- (BOOL)shouldBeDecrypted:(NSDictionary *)payload {
+  return payload[encryptedPayloadKey];
+}
+
+- (BOOL)shouldAlertUnencryptedNotification:(NSDictionary *)payload {
+  return payload[encryptionFailureKey] &&
+      [payload[encryptionFailureKey] isEqualToNumber:@(1)];
+}
+
+- (NSString *)singleDecrypt:(NSString *)data {
+  std::string encryptedData = std::string([data UTF8String]);
+  return [NSString
+      stringWithUTF8String:
+          (comm::NotificationsCryptoModule::decrypt(
+               encryptedData,
+               comm::NotificationsCryptoModule::olmEncryptedTypeMessage,
+               callingProcessName))
+              .c_str()];
+}
+
+- (void)decryptBestAttemptContent {
+  NSString *decryptedSerializedPayload = [self
+      singleDecrypt:self.bestAttemptContent.userInfo[encryptedPayloadKey]];
+  NSDictionary *decryptedPayload = [NSJSONSerialization
+      JSONObjectWithData:[decryptedSerializedPayload
+                             dataUsingEncoding:NSUTF8StringEncoding]
+                 options:0
+                   error:nil];
+
+  NSMutableDictionary *mutableUserInfo =
+      [self.bestAttemptContent.userInfo mutableCopy];
+
+  NSMutableDictionary *mutableAps = nil;
+  if (mutableUserInfo[@"aps"]) {
+    mutableAps = [mutableUserInfo[@"aps"] mutableCopy];
+  }
+
+  NSString *body = decryptedPayload[@"merged"];
+  if (body) {
+    self.bestAttemptContent.body = body;
+    if (mutableAps && mutableAps[@"alert"]) {
+      mutableAps[@"alert"] = body;
+    }
+  }
+
+  NSString *threadID = decryptedPayload[@"threadID"];
+  if (threadID) {
+    self.bestAttemptContent.threadIdentifier = threadID;
+    mutableUserInfo[@"threadID"] = threadID;
+    if (mutableAps) {
+      mutableAps[@"thread-id"] = threadID;
+    }
+  }
+
+  NSString *badgeStr = decryptedPayload[@"badge"];
+  if (badgeStr) {
+    NSNumber *badge = @([badgeStr intValue]);
+    self.bestAttemptContent.badge = badge;
+    if (mutableAps) {
+      mutableAps[@"badge"] = badge;
+    }
+  }
+
+  // The rest have been already decrypted and handled.
+  static NSArray<NSString *> *handledKeys =
+      @[ @"merged", @"badge", @"threadID" ];
+
+  for (NSString *payloadKey in decryptedPayload) {
+    if ([handledKeys containsObject:payloadKey]) {
+      continue;
+    }
+    mutableUserInfo[payloadKey] = decryptedPayload[payloadKey];
+  }
+
+  if (mutableAps) {
+    mutableUserInfo[@"aps"] = mutableAps;
+  }
+  [mutableUserInfo removeObjectForKey:encryptedPayloadKey];
+  self.bestAttemptContent.userInfo = mutableUserInfo;
+}
+
 @end