Ok, I have an internal intranet website created in visual studio 2005, c#.
It was running fine for months, and then all of the sudden a few days I
started getting these errors emailed to me (I have it set up to email me
exceptions). Here is the error. I have gotten this error probably 100 times
in the last 2 days.

I have googled this error to no avail. My program is not doing any
decrypting, I am not on a web farm, I have reset the web server. The website
is internal, not on internet.

Exception Thrown

Module:
http://intranet/WebResource.axd?d=_9PVU2juk255_dSftXLwlg2&t=632967410635716438

Exception Information: System.Security.Cryptography.CryptographicException:
Padding is invalid and cannot be removed.

at System.Security.Cryptography.RijndaelManagedTransform.DecryptData(Byte[]
inputBuffer, Int32 inputOffset, Int32 inputCount, Byte[]& outputBuffer,
Int32 outputOffset, PaddingMode paddingMode, Boolean fLast)

at
System.Security.Cryptography.RijndaelManagedTransform.TransformFinalBlock(Byte[]
inputBuffer, Int32 inputOffset, Int32 inputCount)

at System.Security.Cryptography.CryptoStream.FlushFinalBlock()

at System.Web.Configuration.MachineKeySection.EncryptOrDecryptData(Boolean
fEncrypt, Byte[] buf, Byte[] modifier, Int32 start, Int32 length, Boolean
useValidationSymAlgo)

at System.Web.UI.Page.DecryptString(String s)

at
System.Web.Handlers.AssemblyResourceLoader.System.Web.IHttpHandler.ProcessRequest(HttpContext
context)

at
System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()

at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean&
completedSynchronously)