CryptDecodeObjectEx Bad Tag ERROR (0x8009310b)

I have a .cer file. I can read it and write a buffer through the ReadFile () function. Now I have the buffer and datalen that I had.

And I use this buffer and len to call CryptDecodeObjectEx () function like below line

if ( !CryptDecodeObjectEx( X509_ASN_ENCODING, 
                           (BYTE* )pemPubKey, 
                           (DWORD *)&publicKeyInfoLen ) )


But when I run it via debug I get error code 0x8009310B using GetLastError () function.

How can I fix this? Thank you for your advice.

Additional Information

  • If I use X509_ANY_STRING instead of X509_PUBLIC_KEY_INFO; it works. But it doesn't populate my publicKeyInfo structure. Because of this, I cannot get the public key in it.
  • I have a DER formatted certificate.

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