Specifies standard security algorithms.
Values:
| IG_PDF_STD_SECURITY_METHOD_RC4_V2 | 2 | RC4 algorithm for encryption. |
| IG_PDF_STD_SECURITY_METHOD_AES_V1 | 5 | AES algorithm for encryption with a zero initialized iv. |
| IG_PDF_STD_SECURITY_METHOD_AES_V2 | 6 | AES algorithm for encryption with a random initialized iv. |
| IG_PDF_STD_SECURITY_METHOD_AES_V3 | 7 | AES algorithm for encryption with a 4 byte random iv. |