Present Day
| The Enigma cipher machine |
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Modern ciphers such as Advanced Encryption Standard are not currently susceptible to known-plaintext attacks.
The PKZIP stream cipher used by older versions of the zip format specification is prone to this attack. For example, an attacker with an encrypted ZIP file needs only (part of) one unencrypted file from the archive which forms the "known-plaintext". Then using some publicly available software they can quickly calculate the key required to decrypt the entire archive. To obtain this unencrypted file the attacker could search the website for a suitable file, find it from another archive they can open, or manually try to reconstruct a plaintext file armed with the knowledge of the filename from the encrypted archive. However, the attack does not work on AES-encrypted zip files.
Read more about this topic: Known-plaintext Attack
Famous quotes containing the words present and/or day:
“At present cats have more purchasing power and influence than the poor of this planet. Accidents of geography and colonial history should no longer determine who gets the fish.”
—Derek Wall (b. 1965)
“Noble and wise men once believed in the music of the spheres: noble and wise men still continue to believe in the “moral significance of existence.” But one day even this sphere-music will no longer be audible to them! They will wake up and take note that their ears were dreaming.”
—Friedrich Nietzsche (1844–1900)