CryptoAPI cryptographic service provider (CSP) for this implementation could not be acquired.

[Dave Bailey]

I have an application installed on a web server. When forst intalled it worked fine. The administrator rebooted the server and then when accessing the app the folowing error appears:

CryptoAPI cryptographic service provider (CSP) for this implementation could not be acquired.
I am using DPAPI(Machine Store) to encrypt a connection string. The decryption code is as follows:

private string GetConnectionString()
{
DataProtector dp = new DataProtector(DataProtector.Store.USE_MACHINE_STOR E);

string appSettingValue = ConfigurationSettings.AppSettings["connectionString"];
byte[] dataToDecrypt = Convert.FromBase64String(appSettingValue);
string connStr = Encoding.ASCII.GetString(dp.Decrypt(dataToDecrypt, null));
string connectionString = connStr;

return connectionString;
}

Can anyone provide any help for this problem?

Thanks,

Dave

[Nicholas Paldino [.NET/C# MVP]]

Dave,

You need to show the code for the DataProtector class, as it is not part
of the framework, and I imagine that is where the problem is occuring.

However, since this is in ASP.NET, are you sure that the site is
configured correctly so that the user that the page is being processed under
(ASPNET local user by default), has access to the cryptographic APIs? I
believe you need some sort of rights for this.

Hope this helps.
--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"Dave Bailey" <an*******@discussions.microsoft.com> wrote in message
news:4B**********************************@microsof t.com...

I have an application installed on a web server. When forst intalled it worked fine. The administrator rebooted the server and then when accessing
the app the folowing error appears:
CryptoAPI cryptographic service provider (CSP) for this implementation could not be acquired.

I am using DPAPI(Machine Store) to encrypt a connection string. The decryption code is as follows:
private string GetConnectionString()
{
DataProtector dp = new DataProtector(DataProtector.Store.USE_MACHINE_STOR E);
string appSettingValue = ConfigurationSettings.AppSettings["connectionString"]; byte[] dataToDecrypt = Convert.FromBase64String(appSettingValue);
string connStr = Encoding.ASCII.GetString(dp.Decrypt(dataToDecrypt, null));
string connectionString = connStr;

return connectionString;
}

Can anyone provide any help for this problem?

Thanks,

Dave

[Dave Bailey]

Here is the code for the DataProtector class. By the way, why would it work at first but when the server was rebooted it quit working and threw the error?

using System;
using System.Text;
using System.Runtime.InteropServices;

namespace DataProtection
{
/// <summary>
/// Summary description for Class1.
/// </summary>
public class DataProtector
{
[DllImport("Crypt32.dll", SetLastError=true,
CharSet=System.Runtime.InteropServices.CharSet.Aut o)]
private static extern bool CryptProtectData(
ref DATA_BLOB pDataIn,
String szDataDescr,
ref DATA_BLOB pOptionalEntropy,
IntPtr pvReserved,
ref CRYPTPROTECT_PROMPTSTRUCT pPromptStruct,
int dwFlags,
ref DATA_BLOB pDataOut);
[DllImport("Crypt32.dll", SetLastError=true,
CharSet=System.Runtime.InteropServices.CharSet.Aut o)]
private static extern bool CryptUnprotectData(
ref DATA_BLOB pDataIn,
String szDataDescr,
ref DATA_BLOB pOptionalEntropy,
IntPtr pvReserved,
ref CRYPTPROTECT_PROMPTSTRUCT pPromptStruct,
int dwFlags,
ref DATA_BLOB pDataOut);
[DllImport("kernel32.dll",
CharSet=System.Runtime.InteropServices.CharSet.Aut o)]
private unsafe static extern int FormatMessage(int dwFlags,
ref IntPtr lpSource,
int dwMessageId,
int dwLanguageId,
ref String lpBuffer, int nSize,
IntPtr *Arguments);

[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
internal struct DATA_BLOB
{
public int cbData;
public IntPtr pbData;
}
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
internal struct CRYPTPROTECT_PROMPTSTRUCT
{
public int cbSize;
public int dwPromptFlags;
public IntPtr hwndApp;
public String szPrompt;
}
static private IntPtr NullPtr = ((IntPtr)((int)(0)));
private const int CRYPTPROTECT_UI_FORBIDDEN = 0x1;
private const int CRYPTPROTECT_LOCAL_MACHINE = 0x4;

public enum Store {USE_MACHINE_STORE = 1, USE_USER_STORE};

private Store store;
public DataProtector(Store tempStore)
{
store = tempStore;
}

public byte[] Encrypt(byte[] plainText, byte[] optionalEntropy)
{
bool retVal = false;
DATA_BLOB plainTextBlob = new DATA_BLOB();
DATA_BLOB cipherTextBlob = new DATA_BLOB();
DATA_BLOB entropyBlob = new DATA_BLOB();
CRYPTPROTECT_PROMPTSTRUCT prompt = new CRYPTPROTECT_PROMPTSTRUCT();
InitPromptstruct(ref prompt);
int dwFlags;
try
{
try
{
int bytesSize = plainText.Length;
plainTextBlob.pbData = Marshal.AllocHGlobal(bytesSize);
if(IntPtr.Zero == plainTextBlob.pbData)
{
throw new Exception("Unable to allocate plaintext buffer.");
}
plainTextBlob.cbData = bytesSize;
Marshal.Copy(plainText, 0, plainTextBlob.pbData, bytesSize);
}
catch(Exception ex)
{
throw new Exception("Exception marshalling data. " + ex.Message);
}
if(Store.USE_MACHINE_STORE == store)
{//Using the machine store, should be providing entropy.
dwFlags = CRYPTPROTECT_LOCAL_MACHINE|CRYPTPROTECT_UI_FORBIDD EN;
//Check to see if the entropy is null
if(null == optionalEntropy)
{//Allocate something
optionalEntropy = new byte[0];
}
try
{
int bytesSize = optionalEntropy.Length;
entropyBlob.pbData = Marshal.AllocHGlobal(optionalEntropy.Length);;
if(IntPtr.Zero == entropyBlob.pbData)
{
throw new Exception("Unable to allocate entropy data buffer.");
}
Marshal.Copy(optionalEntropy, 0, entropyBlob.pbData, bytesSize);
entropyBlob.cbData = bytesSize;
}
catch(Exception ex)
{
throw new Exception("Exception entropy marshalling data. " +
ex.Message);
}
}
else
{//Using the user store
dwFlags = CRYPTPROTECT_UI_FORBIDDEN;
}
retVal = CryptProtectData(ref plainTextBlob, "", ref entropyBlob,
IntPtr.Zero, ref prompt, dwFlags,
ref cipherTextBlob);
if(false == retVal)
{
throw new Exception("Encryption failed. " +
GetErrorMessage(Marshal.GetLastWin32Error()));
}
}
catch(Exception ex)
{
throw new Exception("Exception encrypting. " + ex.Message);
}
byte[] cipherText = new byte[cipherTextBlob.cbData];
Marshal.Copy(cipherTextBlob.pbData, cipherText, 0, cipherTextBlob.cbData);
return cipherText;
}

public byte[] Decrypt(byte[] cipherText, byte[] optionalEntropy)
{
bool retVal = false;
DATA_BLOB plainTextBlob = new DATA_BLOB();
DATA_BLOB cipherBlob = new DATA_BLOB();
CRYPTPROTECT_PROMPTSTRUCT prompt = new CRYPTPROTECT_PROMPTSTRUCT();
InitPromptstruct(ref prompt);
try
{
try
{
int cipherTextSize = cipherText.Length;
cipherBlob.pbData = Marshal.AllocHGlobal(cipherTextSize);
if(IntPtr.Zero == cipherBlob.pbData)
{
throw new Exception("Unable to allocate cipherText buffer.");
}
cipherBlob.cbData = cipherTextSize;
Marshal.Copy(cipherText, 0, cipherBlob.pbData, cipherBlob.cbData);
}
catch(Exception ex)
{
throw new Exception("Exception marshalling data. " + ex.Message);
}
DATA_BLOB entropyBlob = new DATA_BLOB();
int dwFlags;
if(Store.USE_MACHINE_STORE == store)
{//Using the machine store, should be providing entropy.
dwFlags = CRYPTPROTECT_LOCAL_MACHINE|CRYPTPROTECT_UI_FORBIDD EN;
//Check to see if the entropy is null
if(null == optionalEntropy)
{//Allocate something
optionalEntropy = new byte[0];
}
try
{
int bytesSize = optionalEntropy.Length;
entropyBlob.pbData = Marshal.AllocHGlobal(bytesSize);
if(IntPtr.Zero == entropyBlob.pbData)
{
throw new Exception("Unable to allocate entropy buffer.");
}
entropyBlob.cbData = bytesSize;
Marshal.Copy(optionalEntropy, 0, entropyBlob.pbData, bytesSize);
}
catch(Exception ex)
{
throw new Exception("Exception entropy marshalling data. " +
ex.Message);
}
}
else
{//Using the user store
dwFlags = CRYPTPROTECT_UI_FORBIDDEN;
}
retVal = CryptUnprotectData(ref cipherBlob, null, ref entropyBlob,
IntPtr.Zero, ref prompt, dwFlags,
ref plainTextBlob);
if(false == retVal)
{
throw new Exception("Decryption failed. " +
GetErrorMessage(Marshal.GetLastWin32Error()));
}
//Free the blob and entropy.
if(IntPtr.Zero != cipherBlob.pbData)
{
Marshal.FreeHGlobal(cipherBlob.pbData);
}
if(IntPtr.Zero != entropyBlob.pbData)
{
Marshal.FreeHGlobal(entropyBlob.pbData);
}
}
catch(Exception ex)
{
throw new Exception("Exception decrypting. " + ex.Message);
}
byte[] plainText = new byte[plainTextBlob.cbData];
Marshal.Copy(plainTextBlob.pbData, plainText, 0, plainTextBlob.cbData);
return plainText;
}

private void InitPromptstruct(ref CRYPTPROTECT_PROMPTSTRUCT ps)
{
ps.cbSize = Marshal.SizeOf(typeof(CRYPTPROTECT_PROMPTSTRUCT));
ps.dwPromptFlags = 0;
ps.hwndApp = NullPtr;
ps.szPrompt = null;
}
private unsafe static String GetErrorMessage(int errorCode)
{
int FORMAT_MESSAGE_ALLOCATE_BUFFER = 0x00000100;
int FORMAT_MESSAGE_IGNORE_INSERTS = 0x00000200;
int FORMAT_MESSAGE_FROM_SYSTEM = 0x00001000;
int messageSize = 255;
String lpMsgBuf = "";
int dwFlags = FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS;
IntPtr ptrlpSource = new IntPtr();
IntPtr prtArguments = new IntPtr();
int retVal = FormatMessage(dwFlags, ref ptrlpSource, errorCode, 0,
ref lpMsgBuf, messageSize, &prtArguments);
if(0 == retVal)
{
throw new Exception("Failed to format message for error code " +
errorCode + ". ");
}
return lpMsgBuf;
}



}
}

[Nicholas Paldino [.NET/C# MVP]]

Dave,

I was thinking that maybe you had it on a dev machine, and then moved it
to another machine, which needed to be rebooted (for some strange reason).

Rebooting the machine should not have an effect. In your code, which
line is it that is throwing the exception? Also, do you have a specific
error code? I can't tell looking through all of the code.

--
- Nicholas Paldino [.NET/C# MVP]
- mv*@spam.guard.caspershouse.com

"Dave Bailey" <an*******@discussions.microsoft.com> wrote in message
news:09**********************************@microsof t.com...

Here is the code for the DataProtector class. By the way, why would it work at first but when the server was rebooted it quit working and threw the
error?
using System;
using System.Text;
using System.Runtime.InteropServices;

namespace DataProtection
{
/// <summary>
/// Summary description for Class1.
/// </summary>
public class DataProtector
{
[DllImport("Crypt32.dll", SetLastError=true,
CharSet=System.Runtime.InteropServices.CharSet.Aut o)]
private static extern bool CryptProtectData(
ref DATA_BLOB pDataIn,
String szDataDescr,
ref DATA_BLOB pOptionalEntropy,
IntPtr pvReserved,
ref CRYPTPROTECT_PROMPTSTRUCT pPromptStruct,
int dwFlags,
ref DATA_BLOB pDataOut);
[DllImport("Crypt32.dll", SetLastError=true,
CharSet=System.Runtime.InteropServices.CharSet.Aut o)]
private static extern bool CryptUnprotectData(
ref DATA_BLOB pDataIn,
String szDataDescr,
ref DATA_BLOB pOptionalEntropy,
IntPtr pvReserved,
ref CRYPTPROTECT_PROMPTSTRUCT pPromptStruct,
int dwFlags,
ref DATA_BLOB pDataOut);
[DllImport("kernel32.dll",
CharSet=System.Runtime.InteropServices.CharSet.Aut o)]
private unsafe static extern int FormatMessage(int dwFlags,
ref IntPtr lpSource,
int dwMessageId,
int dwLanguageId,
ref String lpBuffer, int nSize,
IntPtr *Arguments);

[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
internal struct DATA_BLOB
{
public int cbData;
public IntPtr pbData;
}
[StructLayout(LayoutKind.Sequential, CharSet=CharSet.Unicode)]
internal struct CRYPTPROTECT_PROMPTSTRUCT
{
public int cbSize;
public int dwPromptFlags;
public IntPtr hwndApp;
public String szPrompt;
}
static private IntPtr NullPtr = ((IntPtr)((int)(0)));
private const int CRYPTPROTECT_UI_FORBIDDEN = 0x1;
private const int CRYPTPROTECT_LOCAL_MACHINE = 0x4;

public enum Store {USE_MACHINE_STORE = 1, USE_USER_STORE};

private Store store;
public DataProtector(Store tempStore)
{
store = tempStore;
}

public byte[] Encrypt(byte[] plainText, byte[] optionalEntropy)
{
bool retVal = false;
DATA_BLOB plainTextBlob = new DATA_BLOB();
DATA_BLOB cipherTextBlob = new DATA_BLOB();
DATA_BLOB entropyBlob = new DATA_BLOB();
CRYPTPROTECT_PROMPTSTRUCT prompt = new CRYPTPROTECT_PROMPTSTRUCT();
InitPromptstruct(ref prompt);
int dwFlags;
try
{
try
{
int bytesSize = plainText.Length;
plainTextBlob.pbData = Marshal.AllocHGlobal(bytesSize);
if(IntPtr.Zero == plainTextBlob.pbData)
{
throw new Exception("Unable to allocate plaintext buffer.");
}
plainTextBlob.cbData = bytesSize;
Marshal.Copy(plainText, 0, plainTextBlob.pbData, bytesSize);
}
catch(Exception ex)
{
throw new Exception("Exception marshalling data. " + ex.Message);
}
if(Store.USE_MACHINE_STORE == store)
{//Using the machine store, should be providing entropy.
dwFlags = CRYPTPROTECT_LOCAL_MACHINE|CRYPTPROTECT_UI_FORBIDD EN;
//Check to see if the entropy is null
if(null == optionalEntropy)
{//Allocate something
optionalEntropy = new byte[0];
}
try
{
int bytesSize = optionalEntropy.Length;
entropyBlob.pbData = Marshal.AllocHGlobal(optionalEntropy.Length);;
if(IntPtr.Zero == entropyBlob.pbData)
{
throw new Exception("Unable to allocate entropy data buffer.");
}
Marshal.Copy(optionalEntropy, 0, entropyBlob.pbData, bytesSize);
entropyBlob.cbData = bytesSize;
}
catch(Exception ex)
{
throw new Exception("Exception entropy marshalling data. " +
ex.Message);
}
}
else
{//Using the user store
dwFlags = CRYPTPROTECT_UI_FORBIDDEN;
}
retVal = CryptProtectData(ref plainTextBlob, "", ref entropyBlob,
IntPtr.Zero, ref prompt, dwFlags,
ref cipherTextBlob);
if(false == retVal)
{
throw new Exception("Encryption failed. " +
GetErrorMessage(Marshal.GetLastWin32Error()));
}
}
catch(Exception ex)
{
throw new Exception("Exception encrypting. " + ex.Message);
}
byte[] cipherText = new byte[cipherTextBlob.cbData];
Marshal.Copy(cipherTextBlob.pbData, cipherText, 0, cipherTextBlob.cbData);
return cipherText;
}

public byte[] Decrypt(byte[] cipherText, byte[] optionalEntropy)
{
bool retVal = false;
DATA_BLOB plainTextBlob = new DATA_BLOB();
DATA_BLOB cipherBlob = new DATA_BLOB();
CRYPTPROTECT_PROMPTSTRUCT prompt = new CRYPTPROTECT_PROMPTSTRUCT();
InitPromptstruct(ref prompt);
try
{
try
{
int cipherTextSize = cipherText.Length;
cipherBlob.pbData = Marshal.AllocHGlobal(cipherTextSize);
if(IntPtr.Zero == cipherBlob.pbData)
{
throw new Exception("Unable to allocate cipherText buffer.");
}
cipherBlob.cbData = cipherTextSize;
Marshal.Copy(cipherText, 0, cipherBlob.pbData, cipherBlob.cbData);
}
catch(Exception ex)
{
throw new Exception("Exception marshalling data. " + ex.Message);
}
DATA_BLOB entropyBlob = new DATA_BLOB();
int dwFlags;
if(Store.USE_MACHINE_STORE == store)
{//Using the machine store, should be providing entropy.
dwFlags = CRYPTPROTECT_LOCAL_MACHINE|CRYPTPROTECT_UI_FORBIDD EN;
//Check to see if the entropy is null
if(null == optionalEntropy)
{//Allocate something
optionalEntropy = new byte[0];
}
try
{
int bytesSize = optionalEntropy.Length;
entropyBlob.pbData = Marshal.AllocHGlobal(bytesSize);
if(IntPtr.Zero == entropyBlob.pbData)
{
throw new Exception("Unable to allocate entropy buffer.");
}
entropyBlob.cbData = bytesSize;
Marshal.Copy(optionalEntropy, 0, entropyBlob.pbData, bytesSize);
}
catch(Exception ex)
{
throw new Exception("Exception entropy marshalling data. " +
ex.Message);
}
}
else
{//Using the user store
dwFlags = CRYPTPROTECT_UI_FORBIDDEN;
}
retVal = CryptUnprotectData(ref cipherBlob, null, ref entropyBlob,
IntPtr.Zero, ref prompt, dwFlags,
ref plainTextBlob);
if(false == retVal)
{
throw new Exception("Decryption failed. " +
GetErrorMessage(Marshal.GetLastWin32Error()));
}
//Free the blob and entropy.
if(IntPtr.Zero != cipherBlob.pbData)
{
Marshal.FreeHGlobal(cipherBlob.pbData);
}
if(IntPtr.Zero != entropyBlob.pbData)
{
Marshal.FreeHGlobal(entropyBlob.pbData);
}
}
catch(Exception ex)
{
throw new Exception("Exception decrypting. " + ex.Message);
}
byte[] plainText = new byte[plainTextBlob.cbData];
Marshal.Copy(plainTextBlob.pbData, plainText, 0, plainTextBlob.cbData);
return plainText;
}

private void InitPromptstruct(ref CRYPTPROTECT_PROMPTSTRUCT ps)
{
ps.cbSize = Marshal.SizeOf(typeof(CRYPTPROTECT_PROMPTSTRUCT));
ps.dwPromptFlags = 0;
ps.hwndApp = NullPtr;
ps.szPrompt = null;
}
private unsafe static String GetErrorMessage(int errorCode)
{
int FORMAT_MESSAGE_ALLOCATE_BUFFER = 0x00000100;
int FORMAT_MESSAGE_IGNORE_INSERTS = 0x00000200;
int FORMAT_MESSAGE_FROM_SYSTEM = 0x00001000;
int messageSize = 255;
String lpMsgBuf = "";
int dwFlags = FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS;
IntPtr ptrlpSource = new IntPtr();
IntPtr prtArguments = new IntPtr();
int retVal = FormatMessage(dwFlags, ref ptrlpSource, errorCode, 0,
ref lpMsgBuf, messageSize, &prtArguments);
if(0 == retVal)
{
throw new Exception("Failed to format message for error code " +
errorCode + ". ");
}
return lpMsgBuf;
}



}
}

[Dave Bailey]

Here is the entire error page.

CryptoAPI cryptographic service provider (CSP) for this implementation could not be acquired.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.Security.Cryptography.CryptographicExceptio n: CryptoAPI cryptographic service provider (CSP) for this implementation could not be acquired

Source Error:

An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.

Stack Trace:

[CryptographicException: CryptoAPI cryptographic service provider (CSP) for this implementation could not be acquired.
System.Security.Cryptography.SHA1CryptoServiceProv ider..ctor(CspParameters parameters) +39
System.Security.Cryptography.SHA1CryptoServiceProv ider..ctor() +5

[TargetInvocationException: Exception has been thrown by the target of an invocation.
System.Reflection.RuntimeConstructorInfo.InternalI nvoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean isBinderDefault) +
System.Reflection.RuntimeConstructorInfo.Invoke(Bi ndingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) +49
System.Security.Cryptography.CryptoConfig.CreateFr omName(String name, Object[] args) +41
System.Security.Cryptography.SHA1.Create(String hashName) +
System.Security.Cryptography.HMACSHA1..ctor(Byte[] rgbKey) +11
System.Web.Configuration.ExtendedHMACSHA1.GetHMACS HA1() +37
System.Web.Configuration.MachineKey.HMACSHA1HashFo rData(Byte[] buf, Byte[] modifier, Int32 start, Int32 length) +1
System.Web.Configuration.MachineKey.HashData(Byte[] buf, Byte[] modifier, Int32 start, Int32 length) +7
System.Web.Configuration.MachineKey.GetEncodedData (Byte[] buf, Byte[] modifier, Int32 start, Int32& length) +6
System.Web.UI.LosWriter.CompleteTransforms(TextWri ter output, Boolean enableMac, Byte[] macKey) +19
System.Web.UI.LosFormatter.SerializeInternal(TextW riter output, Object value) +12
System.Web.UI.Page.OnFormRender(HtmlTextWriter writer, String formUniqueID) +14
System.Web.UI.HtmlControls.HtmlForm.RenderChildren (HtmlTextWriter writer) +3
System.Web.UI.HtmlControls.HtmlForm.Render(HtmlTex tWriter output) +26
System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +24
System.Web.UI.Control.RenderChildren(HtmlTextWrite r writer) +7
System.Web.UI.Control.Render(HtmlTextWriter writer) +
System.Web.UI.Control.RenderControl(HtmlTextWriter writer) +24
System.Web.UI.Page.ProcessRequestMain() +192