"RSA Cryptosystem with a backdoor

... worldwide marketing ... of the RSA cryptosystem with a backdoor ... [it] is different from the commonly used RSA cryptosystem. It has a unique feature called the backdoor PD. ... The existence of [a backdoor in] RSA system is due to the subliminal RSA key generator .... [that] can generate the RSA key pairs which can be used in any existent RSA systems. For those who know the backdoor PD can extract the subliminal data easily. For those who do not know the backdoor cannot distinguish the subliminal RSA keys and the regular RSA keys. Practically anything can be put in the subliminal channel. So the backdoor PD can be used to recognized whether a particular key is generated by a given key generator.

... the subliminal RSA cryptosystem has the same strength as the regular RSA cryptosystem. And no method found yet, by looking at only the keys without the knowledge of the backdoor, can tell whether the keys are generated by a regular RSA key generator or by a subliminal RSA key generator.

The existence of such a subliminal RSA key generator places a serious threat on any existing applications which use RSA cryptography. One threat is that the client will not be able to tell whether the key generator he got from his contractor or from the shelve is a regular one or a subliminal one. It will be dangerously incentive for the software engineer to cheat his clients by offering his clients subliminal key generators unlawfully. Another possible threat is to use the subliminal RSA key generator as a weapon in the infowar. One can use the subliminal RSA technology to make an imposter of a regular RSA key generator. Then he can silently replace the regular key generator with the imposter, either manually or via virus. The enemy will not know and will use the imposter. The secretes of the enemy is thus exposed.

The so called "Government Access Cryptosystem" can be implemented with the subliminal RSA key generation technique. The government can easily order all the lawful certificate authorities to accept public key certificate request only for those keys which are generated by a backdoor key generator and the government knows the backdoor. In this way, person_to_person secrecy can be maintained, but nothing is secrete to the government. There is no need to maintain a huge database to hold all the keys of all the people any more. And people can generate keys any way he likes as if no one is watching. Obviously, this concept can extend to "Corporate Access Cryptosystem," and "Cryptosystem with an Access Tree," where the lower level has no secrete to the upper level, but the upper level can keep secrete with the lower level.

A complete development tool for the RSA cryptosystem with a backdoor will be included in the forthcoming toolkit CryptoEngine. "