cryptanalysis question: Does knowing some of the content of the message make the full message vulnerable to decryption?

[Paul R. Ramer]

On January 30, 2014 1:15:08 PM PST, "Donald Morgan Jr." <donaldmorganjr at gmail.com> wrote:
>If you know a user has a signature that they use to always end a
>message
>with, does that data aid in the decryption of the file? Would this
>exploit
>be applicable to symmetric encryption methods as well?

A common form of cryptanalytic research involves trying to find a faster than brute force method of discovering a key when several plaintexts are know.  The symmetric ciphers that are employed in GnuPG are, to my knowledge, very good in their resistance to cryptanalysis, including this method.

Just know that no one is going to attack to the cipher itself to get to your messages.  There are much easier methods such as installing a key logger.  Why beat the door down if you can open the window?

Cheers,

--Paul


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