CertFindExtension

The CertFindExtension function finds the first extension in the CERT_EXTENSION array, as identified by its Object Identifier. Processing a decoded certificate is one way this function gets used. From the decoded certificate, a CERT_INFO structure is derived. From that structure the rgExtension array is retrieved and passed to this function in rgExtensions[]. Then this function can determine whether a particular extension is in the array, and if so, return a pointer to it.

#include <wincrypt.h>
PCERT_EXTENSION WINAPI CertFindExtension(
  LPCSTR pszObjId,                // in
  DWORD cExtensions,              // in
  CERT_EXTENSION rgExtensions[ ]  // in
);
 

Parameters

pszObjId

A pointer to the Object Identifier to use in the search.

cExtensions

The number of extensions in rgExtensions[].

rgExtensions[]

The array of extensions.

Return Values

Returns a pointer to the extension, if one is found. Otherwise, NULL is returned.

Example

// EXAMPLE CODE FOR USING CertFindExtension.
// Finds the first extension in the CERT_EXTENSION
// array, as identified by its Object Identifier.

// Set up the variables.
LPCSTR pszObjId = szOID_RSA_RC4; // Object identifier
DWORD cExtensions = 128;         // # of extensions
CERT_EXTENSION rExtensions[128]; // Array of extensions
CERT_EXTENSION * pResult;        // Pointer to the returned extension

pResult = CertFindExtension(
            pszObjId,       // in - Pointer to object identifier
            cExtensions,    // in - # of extensions in the array
            rExtensions);   // in - The array of attributes

if (!&pResult) {
  cout<< "no extension found "<< endl;
}
else {
  cout<< "extension found at "<< pResult<< endl;
}
 

QuickInfo

  Windows NT: Requires version 4.0 SP3 or later. Available also in IE 3.02 and later.
  Windows: Requires Windows 98 (or Windows 95 with IE 3.02 or later).
  Windows CE: Unsupported.
  Header: Declared in wincrypt.h.
  Import Library: Use crypt32.lib.

See Also

CertFindAttribute, CertFindRDNAttr