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srikanth-lingala / zip4j

A Java library for zip files and streams
Apache License 2.0
2.09k stars 313 forks source link

encrypt decrypt without password #295

Closed croo closed 3 years ago

croo commented 3 years ago

Is there a way to encrypt a zip file witout a password, only using private/public keypairs? I want to make a zip file which can be opened only by a private key.

srikanth-lingala commented 3 years ago

Yes there is. This feature of zip is called Strong Encryption. But this feature is PKWARE Proprietary Technology and is a patent held by them and requires license from them and that is probably the reason we don't see this feature in a lot of zip utilities. Here is a quote from the zip specification:

7.0.1 Portions of the Strong Encryption technology defined in this specification are covered under patents and pending patent applications. Refer to the section in this document entitled "Incorporating PKWARE Proprietary Technology into Your Product" for more information.