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 day, present and/or day:
“One of the most singular facts about the unwritten history of this country is the consummate ability with which Southern influence, Southern ideas and Southern ideals, have from the very beginning even up to the present day, dictated to and domineered over the brain and sinew of this nation.”
—Anna Julia Cooper (1859–1964)
“The present hour is always wealthiest when it is poorer than the future ones, as that is the pleasantest site which affords the pleasantest prospects.”
—Henry David Thoreau (1817–1862)
““If Washington were President now, he would have to learn our ways or lose his next election. Only fools and theorists imagine that our society can be handled with gloves or long poles. One must make one’s self a part of it. If virtue won’t answer our purpose, we must use vice, or our opponents will put us out of office, and this was as true in Washington’s day as it is now, and always will be.””
—Henry Brooks Adams (1838–1918)