property EncryptionType: TXLSEncryptionType read GetEncryptionType write SetEncryptionType
EncryptionPassword. xletAuto (the default) picks RC4 CryptoAPI for BIFF8 and XOR obfuscation for BIFF5. xletXor forces BIFF5 XOR obfuscation only, while xletRC4 forces BIFF8 RC4 standard encryption. When a non-empty password is set and the format is BIFF8, saving emits a FILEPASS record after the workbook BOF and RC4-encrypts the Workbook streamRC4 CryptoAPI output uses a 128-bit key and names the compatible Microsoft Enhanced Cryptographic Provider in the standard header. Summary and document-summary properties are written as ordinary plaintext OLE property streams; the encryption header sets fDocProps to describe that choice correctly. A workbook password protects workbook data and does not encrypt those document properties
Classic RC4 and RC4 CryptoAPI load and save are available in the native Linux/macOS LX_PORTABLE_CORE profile as well as Windows. This property belongs to the Classic XLS facade; encrypted OOXML output has its separate platform contract