Why can only TC uzip packed with TC encrypted zip files?

[blob]

There is a problem with unpacking zzipped with TC files protected with password. Only TC can unpack them, and all other software to unzip reports an error when trying to unpack. Why is that so? It was packed using internal TC zip packer with AES256.

[Horst.Epp]

There is no such problem here !
Packed with TC 8.51a x64 and x86
Unpacked with correct password using
7-Zip 9.34
WinRAR 5.20 beta3

[blob]

There is no such problem here !
Packed with TC 8.51a x64 and x86
Unpacked with correct password using
7-Zip 9.34
WinRAR 5.20 beta3

It was packed with version 8.01 AFAIR. I tried it with the newest version of TC (8.51a), and indeed it works now under 7-zip. However, I already sent the files to people, so they have a problem now.

[milo1012]

Why is that so?

Because AES encryption is still quite new and especially the 256-bit variant is not part of the official standard, thx to WinZip.
And to quote the manual:

Important note: The original ZIP2.0 encryption isn't very strong. It can be decrypted easily when parts of the encrypted files are available as plain text, e.g. a readme file which is encrypted with the same password as the rest. The much more secure AES encryption with 128, 192 or 256 bit key length cannot be decrypted by all ZIP packers, but it is supported by newer WinZIP and PkZip versions.

[blob]

Why is that so?

Because AES encryption is still quite new and especially the 256-bit variant is not part of the official standard, thx to WinZip.

It does not explain why the same version of 7-zip displayed an error when zip file was packed with TC ver 8.01 and managed to unpack successfully when packed with TC ver 8.51a.

[Horst.Epp]

Why is that so?

Because AES encryption is still quite new and especially the 256-bit variant is not part of the official standard, thx to WinZip.

It does not explain why the same version of 7-zip displayed an error when zip file was packed with TC ver 8.01 and managed to unpack successfully when packed with TC ver 8.51a.

For me that are useless discussions.
The actual version of TC is available since April this year.
Sometimes new versions are better than old ones
and it makes sense to update.

[blob]

For me that are useless discussions.

It is not useless to learn why and how things happen. ;P

[blob]

There is another problem (even with the newest version of TC).
7-zip cannot unpack multi-part zip archives made with TC.

[Horst.Epp]

There is another problem (even with the newest version of TC).
7-zip cannot unpack multi-part zip archives made with TC.

Confirmed, but WinRAR has no problems to open.
7-zip had long discussions in the past about ZIP multivolumes and unclear specs.

[ghisler(Author)]

TC is using WinZIP format for multi-volume. The original pkzip multi-volume archives all had the same name, so they could only be put on different disks (or in different directories).

Regarding the encryption, it may be a problem with character encoding of the password. Try to stick with a-z, A-Z, 0-9 and the punctuation marks up to the "}" in character map. If you use accents, some programs may use the DOS encoding, some the Windows encoding, and some even UTF-8.

[blob]

Regarding the encryption, it may be a problem with character encoding of the password. Try to stick with a-z, A-Z, 0-9 and the punctuation marks up to the "}" in character map. If you use accents, some programs may use the DOS encoding, some the Windows encoding, and some even UTF-8.

Thank you for your replies.

The password contained only a-z letters and nothing else.

[ghisler(Author)]

Hmm, no idea then - TC's encryption is compatible with WinZIP, and therefore also with other packers like 7zip or rar...