GeneralSecurityException: Invalid signature. (RewardedAdsVerifier - SSV) - server

Question

I clearly followed this insctructions: https://developers.google.com/admob/ios/rewarded-video-ssv#ssv_callback_parameters
My server - spring v2.1.10 (maven),
To implement server verification, I used:
<dependency>
<groupId>com.google.crypto.tink</groupId>
<artifactId>apps-rewardedads</artifactId>
<version>HEAD-SNAPSHOT</version>
</dependency>
<dependency>
<dependency>
<groupId>com.google.crypto.tink</groupId>
<artifactId>tink</artifactId>
<version>1.2.2</version>
</dependency>
RewardedAdsVerifier.class > https://github.com/google/tink/blob/master/apps/rewardedads/src/main/java/com/google/crypto/tink/apps/rewardedads/RewardedAdsVerifier.java
CryptoTinkLibrary > https://github.com/google/tink
Filling the server on the hosting, I started to configure and check on the site admob.com , but got an HTTP-error 404, on the server i got the following exception:
java.security.GeneralSecurityException: Invalid signature
at com.google.crypto.tink.subtle.EcdsaVerifyJce.verify(EcdsaVerifyJce.java:68)
at com.google.crypto.tink.apps.rewardedads.RewardedAdsVerifier.verify(RewardedAdsVerifier.java:166)
at com.google.crypto.tink.apps.rewardedads.RewardedAdsVerifier.verify(RewardedAdsVerifier.java:151)
at com.appsbybananni.luckybitcoin.services.rewards.RewardService.getLowReward(RewardService.java:44)
at com.appsbybananni.luckybitcoin.controllers.user.ControllerUser.getLowRewards(ControllerUser.java:113)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
at org.springframework.web.method.support.InvocableHandlerMethod.doInvoke(InvocableHandlerMethod.java:190)
at org.springframework.web.method.support.InvocableHandlerMethod.invokeForRequest(InvocableHandlerMethod.java:138)
at org.springframework.web.servlet.mvc.method.annotation.ServletInvocableHandlerMethod.invokeAndHandle(ServletInvocableHandlerMethod.java:105)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.invokeHandlerMethod(RequestMappingHandlerAdapter.java:893)
at org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter.handleInternal(RequestMappingHandlerAdapter.java:798)
at org.springframework.web.servlet.mvc.method.AbstractHandlerMethodAdapter.handle(AbstractHandlerMethodAdapter.java:87)
at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:1040)
at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:943)
at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:1006)
at org.springframework.web.servlet.FrameworkServlet.doGet(FrameworkServlet.java:898)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:634)
at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:883)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:741)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:231)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.HiddenHttpMethodFilter.doFilterInternal(HiddenHttpMethodFilter.java:94)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:119)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:193)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:166)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:202)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:96)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:526)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:139)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:74)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:343)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:408)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:66)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:861)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1579)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:49)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.lang.Thread.run(Thread.java:748)
Signature and key_id are valid and provided by admob.
The second day I can't find a solution to this problem. Please help me.
My Controller:
#RequestMapping(path = "/get_low_reward")
public void getLowRewards(#RequestParam(required = false) String user_id,
#RequestParam(required = false) String ad_network,
#RequestParam(required = false) String ad_unit,
#RequestParam(required = false) String timestamp,
#RequestParam(required = false) String transaction_id,
#RequestParam(required = false) String signature,
#RequestParam(required = false) String key_id) {
String rewardUrl = "https://my.server.ru/path?"
+ "ad_network=" + ad_network
+ "&ad_unit=" + ad_unit
+ "&user_id=" + user_id
+ "&timestamp=" + timestamp
+ "&transaction_id" + transaction_id
+ "&signature=" + signature
+ "&key_id=" + key_id;
RewardService rewardService = new RewardService(userRepository, generalSettingsRepository);
rewardService.getLowReward(rewardUrl, user_id);
Then this code is executed:
try {
RewardedAdsVerifier verifier = new RewardedAdsVerifier.Builder()
.fetchVerifyingPublicKeysWith(RewardedAdsVerifier.KEYS_DOWNLOADER_INSTANCE_PROD)
.build();
verifier.verify(rewardUrl);
.....

Answer 1

I finally found the reason. I know the post is old, but someone might need it.
Firstly, make sure you are encoding each parameter with
URLEncoder.encode(param, StandardCharsets.UTF_8);
Secondly, Make sure you are using correct configuration.
Android
iOS
Unity
There are 3 different setup Requirements for different platforms, the platform on AdMob app should match the setup you are using.