known plain-text attacks

[rhkelly]

Neil Williams wrote:

>>>Not if you choose one that is currently present in GnuPG (including the
>>>IDEA extension). They all are not vulnerable to a known-plaintext attack.

>>This is only true if one takes a view that the cipher in question
>>is 100% resistant to any kind of attack. This is a naive
>>assumption...
>>...Protocols that provide an attacker with a known plain-text should
>>thus be avoided whwnever possible.

> Which means, what? 

Which means that hybrid protocols should be acceptable only when no
adequate symmetric cipher solution exists.

Roger K.