How to decrypt secureZip encrypted files using Bouncy Castle and java?

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We have to automatically send/receive zipped + encrypted hundreds of files per day to/from another company and they desire to use SecureZip by PKWARE at their side for this task.

On our side our application is pure Java. We are using Bouncy Castle (BC) library to try to unzip + decrypt.

We provided the other company our RSA public key (.cer).

They have used our public key to encrypt a test file they sent to us.

They selected AES 256 as symmetric algorithm, together to our RSA public key to encrypt the test file. They used this command:

pkzipc -add -dir=current -recipient="our_public_key" -keypassphrase="password" test.zip example.xml

So, the short question: will BC lib be able to decrypt the test zip file encrypted by SecureZIP and our cert? Or do we have to license SecureZIP for our part necessarily?

Any other tool or solution featuring files zip compression + encryption by certs which can be decrypted using BC?

And if file decryption using BC should be possible, the long question: how exactly? Please post a java example (full if possible).

Thanks in advance.

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javacryptographybouncycastlepkzip
Check this links stackoverflow.com/questions/166340/… and stackoverflow.com/questions/10587561/… – pedrofb

1 Answers

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While the .zip format supports encryption, those does not involve certificates.

So I think PKWARE might be using a proprietary file format. They could be just throwing a OpenPGP on top of a ZIP file, or they could be encrypting the files before zipping.

They have a free reader available: https://www.pkware.com/zip-reader

So perhaps you should just use that instead.