Re: CryptAcquireContext problem

From: Michel Gallant (neutron_at_NOSPAMistar.ca)
Date: 01/28/04

  • Next message: Drew Cooper [MSFT]: "Re: schannel.dll, secur32.dll, and DSCLIENT.EXE redistribution" 
    Date: Tue, 27 Jan 2004 20:13:01 -0500

    There is a discussion on when you can should CRYPT_VERIFYCONTEXT at:
        http://support.microsoft.com/default.aspx?scid=KB;EN-US;Q238187&ID=KB;EN-US;Q238187

    This includes symmetric key generation and use for encryption/decryption, hashing etc..
    I remember however that some of the MSDN samples don't follow this good advice :-)

    - Mitch Gallant
       MVP Security

    "John Banes [MS]" <jbanes@online.microsoft.com> wrote in message
    news:uTxxopT5DHA.2064@TK2MSFTNGP11.phx.gbl...
    > Using the default key container (the one with a name of NULL) turns out to
    > be a really bad idea, and frequently causes problems such as this.
    >
    > If your application doesn't need to use a persistant private key, then you
    > should call CryptAcquireContext with NULL for the pszContainer parameter and
    > CRYPT_VERIFYCONTEXT for the dwFlags parameter. When called this way,
    > CryptAcquireContext should essentially never fail.
    >
    > If your application does need a persistent private key, then you should give
    > its key container a unique name. GUIDs work well for this.
    >
    > Regards,
    > John Banes
    > [Microsoft Security Developer]
    >
    > This posting is provided "AS IS" with no warranties, and confers no rights.
    > Please do not send email directly to this alias. This alias is for newsgroup
    > purposes only.
    >
    > "bluecrest" <bluecrest_cn@hotmail.com> wrote in message
    > news:e0xbpAJ5DHA.1936@TK2MSFTNGP12.phx.gbl...
    > #include "stdafx.h"
    > #include <windows.h>
    > #include <wincrypt.h>
    >
    > int main(int argc, char* argv[])
    > {
    > HCRYPTPROV hProv;
    >
    > if(!CryptAcquireContext(&hProv,
    > NULL,
    > NULL,
    > PROV_RSA_FULL,
    > 0))
    > {
    > if(GetLastError() == NTE_BAD_KEYSET )
    > {
    > CryptAcquireContext(&hProv,
    > NULL,
    > NULL,
    > PROV_RSA_FULL,
    > CRYPT_NEWKEYSET);
    > }
    > else
    > return FALSE;
    > }
    >
    > if(!CryptAcquireContext(&hProv,
    > NULL,
    > NULL,
    > PROV_RSA_FULL,
    > 0))
    > return FALSE;
    >
    > return 0;
    > }
    >
    > the first CryptAcquireContext the return value is zero,
    > the second CryptAcquireContext takes long time to return ,the return value
    > is zero?
    > Any ideas what could be causing this behavior?
    >
    >

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