This is the pseudo encryption method of zip header. The password needs to be decompressed under Windows and can be used normally on the mobile phone. Zip and apk can be pseudo-encrypted. When downloading attachments, use the following command: Decryption command Java-jar zip. Jar xxxx.zip or xxxx.apk, and encrypt the command Java-jar zip. Jar xxxx.zip or xxxx.apk The decrypted or encrypted file will overwrite the original file.