CryptEnumProvidersA function (wincrypt.h)

Possible CSPs include Microsoft Base Cryptographic Provider version 1.0 and Microsoft Enhanced Cryptographic Provider version 1.0.

Syntax

BOOL CryptEnumProvidersA(
  [in]      DWORD dwIndex,
  [in]      DWORD *pdwReserved,
  [in]      DWORD dwFlags,
  [out]     DWORD *pdwProvType,
  [out]     LPSTR szProvName,
  [in, out] DWORD *pcbProvName
);

Parameters

[in] dwIndex

Index of the next provider to be enumerated.

[in] pdwReserved

Reserved for future use and must be NULL.

[in] dwFlags

Reserved for future use and must be zero.

[out] pdwProvType

Address of the DWORD value designating the type of the enumerated provider.

[out] szProvName

A pointer to a buffer that receives the data from the enumerated provider. This is a string including the terminating null character.

This parameter can be NULL to set the size of the name for memory allocation purposes. For more information, see Retrieving Data of Unknown Length.

[in, out] pcbProvName

A pointer to a DWORD value specifying the size, in bytes, of the buffer pointed to by the pszProvName parameter. When the function returns, the DWORD value contains the number of bytes stored in the buffer.

Return value

If the function succeeds, the return value is nonzero (TRUE).

If the function fails, the return value is zero (FALSE). For extended error information, call GetLastError.

The error codes prefaced by NTE are generated by the particular CSP being used. Some possible error codes follow.

Remarks

This function enumerates the providers available on a computer. The provider types can be enumerated by using CryptEnumProviderTypes.

Examples

The following example shows a loop listing all available cryptographic service providers. For another example that uses the CryptEnumProviders function, see Example C Program: Enumerating CSP Providers and Provider Types.

#include <stdio.h>
#include <windows.h>
#include <Wincrypt.h>
#pragma comment(lib, "advapi32.lib")

void main()
{

    //---------------------------------------------------------------
    // Copyright (C) Microsoft.  All rights reserved.
    // Declare and initialize variables.

    DWORD       cbName;
    DWORD       dwType;
    DWORD       dwIndex;
    CHAR        *pszName = NULL; 

    // Print header lines for providers.
    printf("Listing Available Providers:\n");
    printf("Provider type\tProvider Name\n");
    printf("_____________\t__________________"
        "___________________\n");   

    //--------------------------------------------------------------- 
    // Loop through enumerating providers.
    dwIndex = 0;
    while(CryptEnumProviders(
           dwIndex,
           NULL,
           0,
           &dwType,
           NULL,
           &cbName
           ))
    {

        //-----------------------------------------------------------
        //  cbName returns the length of the name of the next 
        //  provider. Allocate memory in a buffer to retrieve 
        //  that name.

        if (!(pszName = (LPTSTR)LocalAlloc(LMEM_ZEROINIT, cbName)))
        {
           printf("ERROR - LocalAlloc failed\n");
           exit(1);
        }
        //-----------------------------------------------------------
        //  Get the provider name.
        if (CryptEnumProviders(
               dwIndex++,
               NULL,
               0,
               &dwType,
               pszName,
               &cbName
               ))
        {
            printf ("     %4.0d\t%s\n",dwType, pszName);
        }
        else
        {
            printf("ERROR - CryptEnumProviders failed.\n");
            exit(1);
        }
        LocalFree(pszName);

    } // End of while loop

    printf("\nProvider types and provider names "
        "have been listed.\n");
}

Requirements

See also

CryptEnumProviderTypes

Service Provider Functions