Re: [java-list] Senhas de Arquivos ZIP em Java

[leandro]

Zip files use a proprietary encryption algorithm to protect an archive. The password is not stored in the archive but is used as a decryption key. There are weaknesses in the algorithm that can be exploited effectively in certain cases. We use different methods to decrypt the file depending on the type of file and whether an unencrypted version of a file in the archive is available. In some cases it may be possible to recover the file contents without finding the password. If you have one unencrypted file that is also in the archive, we can use a known plaintext attack.  This approach is always successful. If your WinZip archive contains five or more files, then we use a collision attack. This exploits a weakness in the encryption algorithm used but does not work with PKZip. Otherwise, we can use a dictionary attack.  This tries potential passwords from a large custom dictionary and is effective for simple passwords. A brute force attack tries every possible combination of characters and is particularly useful for finding short passwords. Brute force attacks are particularly CPU intensive. Eduardo Resende wrote: Alguem sabe como extrair arquivos de um ZIP que estejam protegidos com senha utilizando a java.util.zip ou similar??? Preciso fazer isto urgente! Obrigado Eduardo Resende[EMAIL PROTECTED]CTIS Informática