TEncryptionType Enumeration

How the file is encrypted. This applies only to xls files. Xlsx files are encrypted using the Agile xlsx encryption.

Security note: All xls encryption modes are legacy compatibility options and should not be used for new confidential files. Save as xlsx and use Agile xlsx encryption when the file must be protected.

Syntax

Unit: FlexCel.Core

Members

Name	Value	Description
XorEncryption	0	Excel 95 XOR encryption. This is a legacy compatibility mode and is not recommended for protecting confidential files.
Standard	1	Excel 97/2000 encryption. This is a legacy RC4-based mode and is not recommended for protecting confidential files.
Strong	2	Excel XP/2003 encryption. Note that despite the name, this mode has multiple known vulnerabilities, and it is just marginally better than TEncryptionType.Standard. Both use RC4 algorithm to encrypt, which is weak. If you need files to be really secure, you need to use xlsx (which supports AES), not xls.