SignalR - Decryption key specified has invalid hex characters

Question

I am using SignalR 2.2.0 and MVC 4. When I load my page in Chrome, I receive an error in the console:

http://localhost:8180/signalr/negotiate?clientProtocol=1.5&connectionData=%5B%7B%22name%22%3A%22chathub%22%7D%5D&_=1467627883530 500 (Internal Server Error)

Upon further inspection using Fiddler I can view the stacktrace:

[ConfigurationErrorsException]: Decryption key specified has invalid hex characters. (C:\Users\Foo\web.config line 66)

   at System.Web.Security.Cryptography.MachineKeyMasterKeyProvider.GenerateCryptographicKey(String configAttributeName, String configAttributeValue, Int32 autogenKeyOffset, Int32 autogenKeyCount, String errorResourceString)
   at System.Web.Security.Cryptography.MachineKeyMasterKeyProvider.GetEncryptionKey()
   at System.Web.Security.Cryptography.Purpose.GetDerivedEncryptionKey(IMasterKeyProvider masterKeyProvider, KeyDerivationFunction keyDerivationFunction)
   at System.Web.Security.Cryptography.AspNetCryptoServiceProvider.GetNetFXCryptoService(Purpose purpose, CryptoServiceOptions options)
   at System.Web.Security.Cryptography.AspNetCryptoServiceProvider.GetCryptoService(Purpose purpose, CryptoServiceOptions options)
   at System.Web.Security.MachineKey.Protect(ICryptoServiceProvider cryptoServiceProvider, Byte[] userData, String[] purposes)
   at System.Web.Security.MachineKey.Protect(Byte[] userData, String[] purposes)
   at Microsoft.Owin.Host.SystemWeb.DataProtection.MachineKeyDataProtector.Protect(Byte[] userData)
   at Microsoft.Owin.Security.DataProtection.AppBuilderExtensions.CallDataProtectionProvider.CallDataProtection.Protect(Byte[] userData)
   at Microsoft.AspNet.SignalR.Infrastructure.DataProtectionProviderProtectedData.Protect(String data, String purpose)
   at Microsoft.AspNet.SignalR.PersistentConnection.ProcessNegotiationRequest(HostContext context)
   at Microsoft.AspNet.SignalR.PersistentConnection.ProcessRequest(HostContext context)
   at Microsoft.AspNet.SignalR.Hubs.HubDispatcher.ProcessRequest(HostContext context)
   at Microsoft.AspNet.SignalR.PersistentConnection.ProcessRequest(IDictionary`2 environment)
   at Microsoft.AspNet.SignalR.Owin.Middleware.HubDispatcherMiddleware.Invoke(IOwinContext context)
   at Microsoft.Owin.Infrastructure.OwinMiddlewareTransition.Invoke(IDictionary`2 environment)
   at Microsoft.Owin.Mapping.MapMiddleware.<Invoke>d__0.MoveNext()

From what I've gathered, SignalR is using the machine key to perform some encryption/decryption.

This is what the machine key looks like:

<machineKey decryptionKey="5E329ED7DE2786FCD906E717C97A09BE26B3564BBE0A2B28,IsolateApps" validationKey="A64F709FB47B282CB8331205BC423D63450B4FFC92FE06EC1E00B3AE8B5B1F529A5CD1064F66C08545FC13B013F84153598B29213D5494DD5EC348B537A51DAE,IsolateApps"/>

I'm guessing it's seeing the "IsolateApps" in the decryptionKey/validationKey and throwing an exception ("...invalid hex characters").

If I remove the "IsolateApps" from the keys, I can't log in anymore since I'm using FormsAuthentication which in turn makes use of the keys to encrypt/decrypt. So removing the "IsolateApps" does not seem to be a solution.

PS. The code I'm using is from this tutorial. I have already looked at this answer but it does not solve the problem. I have also tried to add compatibilityMode="Framework20SP1" to the machine key but that does not work either.

Is there way to fix this issue without removing the "IsolateApps" value from the keys in the web config?

score 1 · Answer 1 · answered Jul 06 '16 at 13:21

I have fixed the issue. I decided to remove the ",IsolateApps" attribute from the machine key which stopped giving this exception:

Decryption key specified has invalid hex characters

Removing this attribute meant I could not log in anymore (since the machine key has technically changed) which forced me to reset my account password. Once I reset the password I could continue with logging in.

Once I was able to log in I was receiving this error:

ws://xxxxx/signalr/connect?transport=webSockets&clientProtocol=1.5&connectionToken=xxxxx' failed: Connection closed before receiving a handshake response.

This exception was only being thrown in Chrome.

SignalR fell back onto server sent events because the web socket handshakes weren't successful. After many hours of debugging I solved the issue by adding this to the web config:

<system.web>
    <compilation debug="true" targetFramework="4.5" />
    <httpRuntime targetFramework="4.5" />
    <pages controlRenderingCompatibilityVersion="4.0" />
</system.web>

Once that was added, SignalR was functioning as excepted.

Removing IsolateApps worked for me, so thank you. However, I'm still falling back to SSE after making that config change. :( — Facio Ratio, Mar 22 '17 at 21:54

SignalR - Decryption key specified has invalid hex characters

1 Answers1