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