I am using cknfast.dll x64 version with NCryptoki 1.6.1.4. My desktop test application working perfectly. I run test application multiple at desktop and applications sign with same private key.

I am using same code in web service and hosted in IIS. When I make multiple request I am getting two error in Windows event manager:

Firs error:

Application: w3wp.exe
Framework Version: v4.0.30319
Description: The process was terminated due to an unhandled exception.
Exception Info: System.AccessViolationException
 

Second error:

Faulting application name: w3wp.exe, version: 7.5.7601.17514, time stamp: 0x4ce7afa2
Faulting module name: cknfast-64.dll, version: 1.90.1.0, time stamp: 0x51f9280d
Exception code: 0xc0000005
Fault offset: 0x0000000000006943
Faulting process id: 0x1228
Faulting application start time: 0x01d05e99f49e5526
Faulting application path: c:\windows\system32\inetsrv\w3wp.exe
Faulting module path: C:\inetpub\wwwroot\SignatureService\bin\cknfast-64.dll

I try to fix error with ServiceBehavior InstanceContextMode and ConcurrencyMode. I try some combination but not working.

Is it possible to use multiple key in one session?

We are using SignInit before sign and use private key as parameter. If I have multiple private key, can I use one of them in same session? Is there any complication in multithread application?