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 GetConnectionSt ring()
{
DataProtector dp = new DataProtector(D ataProtector.St ore.USE_MACHINE _STORE);

string appSettingValue = ConfigurationSe ttings.AppSetti ngs["connectionStri ng"];
byte[] dataToDecrypt = Convert.FromBas e64String(appSe ttingValue);
string connStr = Encoding.ASCII. GetString(dp.De crypt(dataToDec rypt,null));
string connectionStrin g = connStr;

return connectionStrin g;
}

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.co m

"Dave Bailey" <an*******@disc ussions.microso ft.com> wrote in message
news:4B******** *************** ***********@mic rosoft.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 GetConnectionSt ring()
{
DataProtector dp = new DataProtector(D ataProtector.St ore.USE_MACHINE _STORE);
string appSettingValue = ConfigurationSe ttings.AppSetti ngs["connectionStri ng"]; byte[] dataToDecrypt = Convert.FromBas e64String(appSe ttingValue);
string connStr = Encoding.ASCII. GetString(dp.De crypt(dataToDec rypt,null));
string connectionStrin g = connStr;

return connectionStrin g;
}

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("Cryp t32.dll", SetLastError=tr ue,
CharSet=System. Runtime.Interop Services.CharSe t.Auto)]
private static extern bool CryptProtectDat a(
ref DATA_BLOB pDataIn,
String szDataDescr,
ref DATA_BLOB pOptionalEntrop y,
IntPtr pvReserved,
ref CRYPTPROTECT_PR OMPTSTRUCT pPromptStruct,
int dwFlags,
ref DATA_BLOB pDataOut);
[DllImport("Cryp t32.dll", SetLastError=tr ue,
CharSet=System. Runtime.Interop Services.CharSe t.Auto)]
private static extern bool CryptUnprotectD ata(
ref DATA_BLOB pDataIn,
String szDataDescr,
ref DATA_BLOB pOptionalEntrop y,
IntPtr pvReserved,
ref CRYPTPROTECT_PR OMPTSTRUCT pPromptStruct,
int dwFlags,
ref DATA_BLOB pDataOut);
[DllImport("kern el32.dll",
CharSet=System. Runtime.Interop Services.CharSe t.Auto)]
private unsafe static extern int FormatMessage(i nt dwFlags,
ref IntPtr lpSource,
int dwMessageId,
int dwLanguageId,
ref String lpBuffer, int nSize,
IntPtr *Arguments);

[StructLayout(La youtKind.Sequen tial, CharSet=CharSet .Unicode)]
internal struct DATA_BLOB
{
public int cbData;
public IntPtr pbData;
}
[StructLayout(La youtKind.Sequen tial, CharSet=CharSet .Unicode)]
internal struct CRYPTPROTECT_PR OMPTSTRUCT
{
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_LO CAL_MACHINE = 0x4;

public enum Store {USE_MACHINE_ST ORE = 1, USE_USER_STORE} ;

private Store store;
public DataProtector(S tore 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_PR OMPTSTRUCT prompt = new CRYPTPROTECT_PR OMPTSTRUCT();
InitPromptstruc t(ref prompt);
int dwFlags;
try
{
try
{
int bytesSize = plainText.Lengt h;
plainTextBlob.p bData = Marshal.AllocHG lobal(bytesSize );
if(IntPtr.Zero == plainTextBlob.p bData)
{
throw new Exception("Unab le to allocate plaintext buffer.");
}
plainTextBlob.c bData = bytesSize;
Marshal.Copy(pl ainText, 0, plainTextBlob.p bData, bytesSize);
}
catch(Exception ex)
{
throw new Exception("Exce ption marshalling data. " + ex.Message);
}
if(Store.USE_MA CHINE_STORE == store)
{//Using the machine store, should be providing entropy.
dwFlags = CRYPTPROTECT_LO CAL_MACHINE|CRY PTPROTECT_UI_FO RBIDDEN;
//Check to see if the entropy is null
if(null == optionalEntropy )
{//Allocate something
optionalEntropy = new byte[0];
}
try
{
int bytesSize = optionalEntropy .Length;
entropyBlob.pbD ata = Marshal.AllocHG lobal(optionalE ntropy.Length); ;
if(IntPtr.Zero == entropyBlob.pbD ata)
{
throw new Exception("Unab le to allocate entropy data buffer.");
}
Marshal.Copy(op tionalEntropy, 0, entropyBlob.pbD ata, bytesSize);
entropyBlob.cbD ata = bytesSize;
}
catch(Exception ex)
{
throw new Exception("Exce ption entropy marshalling data. " +
ex.Message);
}
}
else
{//Using the user store
dwFlags = CRYPTPROTECT_UI _FORBIDDEN;
}
retVal = CryptProtectDat a(ref plainTextBlob, "", ref entropyBlob,
IntPtr.Zero, ref prompt, dwFlags,
ref cipherTextBlob) ;
if(false == retVal)
{
throw new Exception("Encr yption failed. " +
GetErrorMessage (Marshal.GetLas tWin32Error())) ;
}
}
catch(Exception ex)
{
throw new Exception("Exce ption encrypting. " + ex.Message);
}
byte[] cipherText = new byte[cipherTextBlob. cbData];
Marshal.Copy(ci pherTextBlob.pb Data, 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_PR OMPTSTRUCT prompt = new CRYPTPROTECT_PR OMPTSTRUCT();
InitPromptstruc t(ref prompt);
try
{
try
{
int cipherTextSize = cipherText.Leng th;
cipherBlob.pbDa ta = Marshal.AllocHG lobal(cipherTex tSize);
if(IntPtr.Zero == cipherBlob.pbDa ta)
{
throw new Exception("Unab le to allocate cipherText buffer.");
}
cipherBlob.cbDa ta = cipherTextSize;
Marshal.Copy(ci pherText, 0, cipherBlob.pbDa ta, cipherBlob.cbDa ta);
}
catch(Exception ex)
{
throw new Exception("Exce ption marshalling data. " + ex.Message);
}
DATA_BLOB entropyBlob = new DATA_BLOB();
int dwFlags;
if(Store.USE_MA CHINE_STORE == store)
{//Using the machine store, should be providing entropy.
dwFlags = CRYPTPROTECT_LO CAL_MACHINE|CRY PTPROTECT_UI_FO RBIDDEN;
//Check to see if the entropy is null
if(null == optionalEntropy )
{//Allocate something
optionalEntropy = new byte[0];
}
try
{
int bytesSize = optionalEntropy .Length;
entropyBlob.pbD ata = Marshal.AllocHG lobal(bytesSize );
if(IntPtr.Zero == entropyBlob.pbD ata)
{
throw new Exception("Unab le to allocate entropy buffer.");
}
entropyBlob.cbD ata = bytesSize;
Marshal.Copy(op tionalEntropy, 0, entropyBlob.pbD ata, bytesSize);
}
catch(Exception ex)
{
throw new Exception("Exce ption entropy marshalling data. " +
ex.Message);
}
}
else
{//Using the user store
dwFlags = CRYPTPROTECT_UI _FORBIDDEN;
}
retVal = CryptUnprotectD ata(ref cipherBlob, null, ref entropyBlob,
IntPtr.Zero, ref prompt, dwFlags,
ref plainTextBlob);
if(false == retVal)
{
throw new Exception("Decr yption failed. " +
GetErrorMessage (Marshal.GetLas tWin32Error())) ;
}
//Free the blob and entropy.
if(IntPtr.Zero != cipherBlob.pbDa ta)
{
Marshal.FreeHGl obal(cipherBlob .pbData);
}
if(IntPtr.Zero != entropyBlob.pbD ata)
{
Marshal.FreeHGl obal(entropyBlo b.pbData);
}
}
catch(Exception ex)
{
throw new Exception("Exce ption decrypting. " + ex.Message);
}
byte[] plainText = new byte[plainTextBlob.c bData];
Marshal.Copy(pl ainTextBlob.pbD ata, plainText, 0, plainTextBlob.c bData);
return plainText;
}

private void InitPromptstruc t(ref CRYPTPROTECT_PR OMPTSTRUCT ps)
{
ps.cbSize = Marshal.SizeOf( typeof(CRYPTPRO TECT_PROMPTSTRU CT));
ps.dwPromptFlag s = 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(d wFlags, ref ptrlpSource, errorCode, 0,
ref lpMsgBuf, messageSize, &prtArgument s);
if(0 == retVal)
{
throw new Exception("Fail ed 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.co m

"Dave Bailey" <an*******@disc ussions.microso ft.com> wrote in message
news:09******** *************** ***********@mic rosoft.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("Cryp t32.dll", SetLastError=tr ue,
CharSet=System. Runtime.Interop Services.CharSe t.Auto)]
private static extern bool CryptProtectDat a(
ref DATA_BLOB pDataIn,
String szDataDescr,
ref DATA_BLOB pOptionalEntrop y,
IntPtr pvReserved,
ref CRYPTPROTECT_PR OMPTSTRUCT pPromptStruct,
int dwFlags,
ref DATA_BLOB pDataOut);
[DllImport("Cryp t32.dll", SetLastError=tr ue,
CharSet=System. Runtime.Interop Services.CharSe t.Auto)]
private static extern bool CryptUnprotectD ata(
ref DATA_BLOB pDataIn,
String szDataDescr,
ref DATA_BLOB pOptionalEntrop y,
IntPtr pvReserved,
ref CRYPTPROTECT_PR OMPTSTRUCT pPromptStruct,
int dwFlags,
ref DATA_BLOB pDataOut);
[DllImport("kern el32.dll",
CharSet=System. Runtime.Interop Services.CharSe t.Auto)]
private unsafe static extern int FormatMessage(i nt dwFlags,
ref IntPtr lpSource,
int dwMessageId,
int dwLanguageId,
ref String lpBuffer, int nSize,
IntPtr *Arguments);

[StructLayout(La youtKind.Sequen tial, CharSet=CharSet .Unicode)]
internal struct DATA_BLOB
{
public int cbData;
public IntPtr pbData;
}
[StructLayout(La youtKind.Sequen tial, CharSet=CharSet .Unicode)]
internal struct CRYPTPROTECT_PR OMPTSTRUCT
{
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_LO CAL_MACHINE = 0x4;

public enum Store {USE_MACHINE_ST ORE = 1, USE_USER_STORE} ;

private Store store;
public DataProtector(S tore 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_PR OMPTSTRUCT prompt = new CRYPTPROTECT_PR OMPTSTRUCT();
InitPromptstruc t(ref prompt);
int dwFlags;
try
{
try
{
int bytesSize = plainText.Lengt h;
plainTextBlob.p bData = Marshal.AllocHG lobal(bytesSize );
if(IntPtr.Zero == plainTextBlob.p bData)
{
throw new Exception("Unab le to allocate plaintext buffer.");
}
plainTextBlob.c bData = bytesSize;
Marshal.Copy(pl ainText, 0, plainTextBlob.p bData, bytesSize);
}
catch(Exception ex)
{
throw new Exception("Exce ption marshalling data. " + ex.Message);
}
if(Store.USE_MA CHINE_STORE == store)
{//Using the machine store, should be providing entropy.
dwFlags = CRYPTPROTECT_LO CAL_MACHINE|CRY PTPROTECT_UI_FO RBIDDEN;
//Check to see if the entropy is null
if(null == optionalEntropy )
{//Allocate something
optionalEntropy = new byte[0];
}
try
{
int bytesSize = optionalEntropy .Length;
entropyBlob.pbD ata = Marshal.AllocHG lobal(optionalE ntropy.Length); ;
if(IntPtr.Zero == entropyBlob.pbD ata)
{
throw new Exception("Unab le to allocate entropy data buffer.");
}
Marshal.Copy(op tionalEntropy, 0, entropyBlob.pbD ata, bytesSize);
entropyBlob.cbD ata = bytesSize;
}
catch(Exception ex)
{
throw new Exception("Exce ption entropy marshalling data. " +
ex.Message);
}
}
else
{//Using the user store
dwFlags = CRYPTPROTECT_UI _FORBIDDEN;
}
retVal = CryptProtectDat a(ref plainTextBlob, "", ref entropyBlob,
IntPtr.Zero, ref prompt, dwFlags,
ref cipherTextBlob) ;
if(false == retVal)
{
throw new Exception("Encr yption failed. " +
GetErrorMessage (Marshal.GetLas tWin32Error())) ;
}
}
catch(Exception ex)
{
throw new Exception("Exce ption encrypting. " + ex.Message);
}
byte[] cipherText = new byte[cipherTextBlob. cbData];
Marshal.Copy(ci pherTextBlob.pb Data, 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_PR OMPTSTRUCT prompt = new CRYPTPROTECT_PR OMPTSTRUCT();
InitPromptstruc t(ref prompt);
try
{
try
{
int cipherTextSize = cipherText.Leng th;
cipherBlob.pbDa ta = Marshal.AllocHG lobal(cipherTex tSize);
if(IntPtr.Zero == cipherBlob.pbDa ta)
{
throw new Exception("Unab le to allocate cipherText buffer.");
}
cipherBlob.cbDa ta = cipherTextSize;
Marshal.Copy(ci pherText, 0, cipherBlob.pbDa ta, cipherBlob.cbDa ta);
}
catch(Exception ex)
{
throw new Exception("Exce ption marshalling data. " + ex.Message);
}
DATA_BLOB entropyBlob = new DATA_BLOB();
int dwFlags;
if(Store.USE_MA CHINE_STORE == store)
{//Using the machine store, should be providing entropy.
dwFlags = CRYPTPROTECT_LO CAL_MACHINE|CRY PTPROTECT_UI_FO RBIDDEN;
//Check to see if the entropy is null
if(null == optionalEntropy )
{//Allocate something
optionalEntropy = new byte[0];
}
try
{
int bytesSize = optionalEntropy .Length;
entropyBlob.pbD ata = Marshal.AllocHG lobal(bytesSize );
if(IntPtr.Zero == entropyBlob.pbD ata)
{
throw new Exception("Unab le to allocate entropy buffer.");
}
entropyBlob.cbD ata = bytesSize;
Marshal.Copy(op tionalEntropy, 0, entropyBlob.pbD ata, bytesSize);
}
catch(Exception ex)
{
throw new Exception("Exce ption entropy marshalling data. " +
ex.Message);
}
}
else
{//Using the user store
dwFlags = CRYPTPROTECT_UI _FORBIDDEN;
}
retVal = CryptUnprotectD ata(ref cipherBlob, null, ref entropyBlob,
IntPtr.Zero, ref prompt, dwFlags,
ref plainTextBlob);
if(false == retVal)
{
throw new Exception("Decr yption failed. " +
GetErrorMessage (Marshal.GetLas tWin32Error())) ;
}
//Free the blob and entropy.
if(IntPtr.Zero != cipherBlob.pbDa ta)
{
Marshal.FreeHGl obal(cipherBlob .pbData);
}
if(IntPtr.Zero != entropyBlob.pbD ata)
{
Marshal.FreeHGl obal(entropyBlo b.pbData);
}
}
catch(Exception ex)
{
throw new Exception("Exce ption decrypting. " + ex.Message);
}
byte[] plainText = new byte[plainTextBlob.c bData];
Marshal.Copy(pl ainTextBlob.pbD ata, plainText, 0, plainTextBlob.c bData);
return plainText;
}

private void InitPromptstruc t(ref CRYPTPROTECT_PR OMPTSTRUCT ps)
{
ps.cbSize = Marshal.SizeOf( typeof(CRYPTPRO TECT_PROMPTSTRU CT));
ps.dwPromptFlag s = 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(d wFlags, ref ptrlpSource, errorCode, 0,
ref lpMsgBuf, messageSize, &prtArgument s);
if(0 == retVal)
{
throw new Exception("Fail ed 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.C ryptographicExc eption: 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:

[CryptographicEx ception: CryptoAPI cryptographic service provider (CSP) for this implementation could not be acquired.
System.Security .Cryptography.S HA1CryptoServic eProvider..ctor (CspParameters parameters) +39
System.Security .Cryptography.S HA1CryptoServic eProvider..ctor () +5

[TargetInvocatio nException: Exception has been thrown by the target of an invocation.
System.Reflecti on.RuntimeConst ructorInfo.Inte rnalInvoke(Bind ingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture, Boolean isBinderDefault ) +
System.Reflecti on.RuntimeConst ructorInfo.Invo ke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture) +49
System.Security .Cryptography.C ryptoConfig.Cre ateFromName(Str ing name, Object[] args) +41
System.Security .Cryptography.S HA1.Create(Stri ng hashName) +
System.Security .Cryptography.H MACSHA1..ctor(B yte[] rgbKey) +11
System.Web.Conf iguration.Exten dedHMACSHA1.Get HMACSHA1() +37
System.Web.Conf iguration.Machi neKey.HMACSHA1H ashForData(Byte[] buf, Byte[] modifier, Int32 start, Int32 length) +1
System.Web.Conf iguration.Machi neKey.HashData( Byte[] buf, Byte[] modifier, Int32 start, Int32 length) +7
System.Web.Conf iguration.Machi neKey.GetEncode dData(Byte[] buf, Byte[] modifier, Int32 start, Int32& length) +6
System.Web.UI.L osWriter.Comple teTransforms(Te xtWriter output, Boolean enableMac, Byte[] macKey) +19
System.Web.UI.L osFormatter.Ser ializeInternal( TextWriter output, Object value) +12
System.Web.UI.P age.OnFormRende r(HtmlTextWrite r writer, String formUniqueID) +14
System.Web.UI.H tmlControls.Htm lForm.RenderChi ldren(HtmlTextW riter writer) +3
System.Web.UI.H tmlControls.Htm lForm.Render(Ht mlTextWriter output) +26
System.Web.UI.C ontrol.RenderCo ntrol(HtmlTextW riter writer) +24
System.Web.UI.C ontrol.RenderCh ildren(HtmlText Writer writer) +7
System.Web.UI.C ontrol.Render(H tmlTextWriter writer) +
System.Web.UI.C ontrol.RenderCo ntrol(HtmlTextW riter writer) +24
System.Web.UI.P age.ProcessRequ estMain() +192