ENCRYPTION
ENCRYPTION = 1
General Purpose Bit Flag mask for encrypted data.
Bit 0: If set, indicates that the file is encrypted.
General purpose bit flag constants.
DATA_DESCRIPTOR = 8
General Purpose Bit Flag mask for data descriptor.
Bit 3: If this bit is set, the fields crc-32, compressed size and uncompressed size are set to zero in the local header. The correct values are put in the data descriptor immediately following the compressed data.
STRONG_ENCRYPTION = 64
General Purpose Bit Flag mask for strong encryption.
Bit 6: Strong encryption. If this bit is set, you MUST set the version needed to extract value to at least 50 and you MUST also set bit 0. If AES encryption is used, the version needed to extract value MUST be at least 51.