22 lines
1.0 KiB
Plaintext
22 lines
1.0 KiB
Plaintext
This package implements an algorithm for breaking the PkZip cipher that was
|
|
devised by Eli Biham and Paul Kocher.
|
|
|
|
This program applies a known plaintext attack to an encrypted file.
|
|
A known-plaintext-attack recovers a password using the encrypted file and
|
|
(part of) the unencrypted file.
|
|
|
|
Please note that cryptographers use the word 'plaintext' for any kind of
|
|
unencrypted data - not necessarily readable ASCII text.
|
|
|
|
Before you ask why somebody may want to know the password when he already knows
|
|
the plaintext think of the following situations:
|
|
|
|
- Usually there's a large number of files in a ZIP-archive. Usually all these
|
|
files are encrypted using the same password. So if you know one of the files,
|
|
you can recover the password and decrypt the other files.
|
|
- You need to know only a part of the plaintext (at least 13 bytes). Many files
|
|
have commonly known headers, like DOS .EXE-files. Knowing a reasonably long
|
|
header you can recover the password and decrypt the entire file.
|
|
|
|
WWW: http://www.unix-ag.uni-kl.de/~conrad/krypto/pkcrack.html
|