There is no hash. The zipping process at a high level works as follows ... 1) File(s) are compressed and a CRC32 is generated.The Checksum is placed in the hea

There is no hash. The zipping process at a high level works as follows ... 1) File(s) are compressed and a CRC32 is generated.The Checksum is placed in the header. 2) The file body is encrypted but the CRC32 is not. 3) A user tries to unzip and supplies a password. Irrespective of whether the password is correct or not the zip is decompressed and the Checksum is compared against the value in the header. So there is no separate password for encryption/decryption like you ask.