CredUnprotectA function (wincred.h)

Article
02/22/2024

The CredUnprotect function decrypts credentials that were previously encrypted by using the CredProtect function. The credentials must have been encrypted in the same security context in which CredUnprotect is called.

Syntax

BOOL CredUnprotectA(
  [in]      BOOL  fAsSelf,
  [in]      LPSTR pszProtectedCredentials,
  [in]      DWORD cchProtectedCredentials,
  [out]     LPSTR pszCredentials,
  [in, out] DWORD *pcchMaxChars
);

Parameters

[in] fAsSelf

Set to TRUE to specify that the credentials were encrypted in the security context of the current process. Set to FALSE to specify that credentials were encrypted in the security context of the calling thread security context.

[in] pszProtectedCredentials

A pointer to a string that specifies the encrypted credentials.

[in] cchProtectedCredentials

The size, in characters, of the pszProtectedCredentials buffer.

[out] pszCredentials

A pointer to a string that, on output, receives the decrypted credentials.

[in, out] pcchMaxChars

The size, in characters of the pszCredentials buffer. On output, if the pszCredentials is not of sufficient size to receive the encrypted credentials, this parameter specifies the required size, in characters, of the pszCredentials buffer.

Return value

TRUE if the function succeeds; otherwise, FALSE.

For extended error information, call the GetLastError function. The following table shows common values for the GetLastError function.

Return code/value	Description
ERROR_NOT_CAPABLE	The security context used to encrypt the credentials is different from the security context used to decrypt the credentials.
ERROR_INSUFFICIENT_BUFFER	The pszCredentials buffer was of insufficient size.

Remarks

Note

The wincred.h header defines CredUnprotect as an alias which automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.

Requirements

Requirement	Value
Minimum supported client	Windows Vista [desktop apps only]
Minimum supported server	Windows Server 2008 [desktop apps only]
Target Platform	Windows
Header	wincred.h
Library	Advapi32.lib
DLL	Advapi32.dll

Share via