CryptHashSessionKey info  Overview  Group

The CryptHashSessionKey function is used to compute the cryptographic hash on a key object. This function can be called multiple times with the same hash handle to compute the hash on multiple keys. Calls to CryptHashSessionKey can be interspersed with calls to CryptHashData.

Before calling this function the CryptCreateHash function must be called to get a handle to a hash object.

BOOL CRYPTFUNC CryptHashSessionKey(

Parameters

hHash

[in] A handle to the hash object. An application obtains this handle using the CryptCreateHash function.

hKey

[in] A handle to the key object to be hashed.

dwFlags

[in] The flag values. This parameter is reserved for future use and should always be zero.

Return Values

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To retrieve extended error information, use the GetLastError function.

The following table lists the error codes most commonly returned by the GetLastError function. The error codes prefaced by “NTE” are generated by the particular CSP you are using.

Example

#include <wincrypt.h>



HCRYPTPROV hProv = 0;

HCRYPTHASH hHash = 0;

HCRYPTKEY hKey   = 0;



// Get handle to the default provider.

if(!CryptAcquireContext(&hProv, NULL, NULL, PROV_RSA_FULL, 0)) {

    printf("Error %x during CryptAcquireContext!\n", GetLastError());

    goto done;

}



// Create hash object.

if(!CryptCreateHash(hProv, CALG_MD5, 0, 0, &hHash)) {

    printf("Error %x during CryptBeginHash!\n", GetLastError());

    goto done;

}



// Create random session key.

if(!CryptGenKey(hProv, CALG_RC2, CRYPT_EXPORTABLE, &hKey)) {

    printf("Error %x during CryptGenKey!\n", GetLastError());

    goto done;

}



// Hash session key.

if(!CryptHashSessionKey(hHash, hKey, 0)) {

    printf("Error %x during CryptHashSessionKey!\n", GetLastError());

    goto done;

}



// Use the hash object for something.

...



done:



// Destroy hash object.

if(hHash) CryptDestroyHash(hHash);



// Destroy session key.

if(hKey) CryptDestroyKey(hKey);



// Release CSP handle.

if(hProv) CryptReleaseContext(hProv,0);

 

See Also

CryptCreateHash, CryptGenKey, CryptHashData 

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