The CPDuplicateKey function is used to make an exact copy of a key and the state the key is in. Some keys have an associated state such as example, an initialization vector or a salt value.
BOOL CPDuplicateKey(
HCRYPTPROV hProv, // in
HCRYPTKEY hKey, // in
DWORD *pdwReserved, // in
DWORD dwFlags, // in
HCRYPTKEY* phKey // out
);
If the function succeeds, the return value is TRUE; Otherwise, return FALSE. When FALSE is returned, the appropriate error code (see the following table) must be set via SetLastError.
Error | Description |
---|---|
ERROR_CALL_NOT_IMPLEMENTED | Because this is a new function, existing CSPs may not implement it. This error is returned if the CSP does not support this function. |
ERROR_INVALID_PARAMETER | One of the parameters contains an invalid value. This is most often an illegal pointer. |
NTE_BAD_KEY | The handle to the original key is not valid. |
CPDuplicateKey is used to make copies of keys and the exact state of the key. For example, a caller may want to encrypt two separate messages with the same key, but with different salt values. The key could be generated, a duplicate would be made with the CPDuplicateKey function, and then the appropriate salt value would be set on each key with the CPSetKeyParam function.
CPDestroyKey must be called to destroy any keys that are created with CPDuplicateKey. Destroying the original key does not cause the duplicate key to be destroyed. Once a duplicate key is made, it is separate from the original key. There is no shared state between the two keys.
CPDestroyKey, CryptDuplicateKey