An idea: If one does it, then one Should at Least try to do it Well
Posted Aug 12, 2013 9:46 UTC (Mon) by martin_vahi
In reply to: Web-(developer)-oriented Crypto Algorithm
Parent article: Gräßlin: FLOSS after Prism: Privacy by Default
The short answer is: TXOR and one-time pad are symmetric-key algorithms and therefore do not address the scenario that You described.
The motivation for rejecting public-key cryptography, regardless of crypto algorithm, is as follows:
That is to say:
There is a bijection between cleartext and ciphertext and the function_2 is an inverse function of the function_1.
In the case of all public key cryptography algorithms, one of the parts of the key pair is public. As the encryption/decryption algorithm is also public, one of the functions, function_1 or function_2 is always public.
It is only a matter of mathematical skill, how to construct function_1 or function_2, if it is firmly known that the publicly known function definitely has a reverse function.
The fact that I'm dumb enough to fail the task, does not mean that others, professional mathematicians, who work on it as part of their day-job, may-be, but not only, in the NSA, can't solve it.
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