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If the cypher being used is secure, encrypting a block of 1s or 0s will generate an apparently random stream of 0s and 1s. There will be no way to determine th
by deanfranks 13y ago
If the cypher being used is secure, encrypting a block of 1s or 0s will generate an apparently random stream of 0s and 1s. There will be no way to determine the private key from the output of encrypting a block of known data with the public key.
- aa0 13y agoCouldn't a cross-comparison be used, encrypting different known blocks and observing certain key properties? I would imagine that any kind of reversible operation would be able to be deduced if it can be applied to specific data that reveals its true form/operation.
- deanfranks 13y agoNot with a strong cypher. Any single bit change in the source will result in what looks like a new pseudo-random output. Determining the private key given the public key in RSA-2048 requires factorizing large blocks of very large numbers which is not practical given current computing hardware. People are working on "smart" attacks that solve the factorization problem from a theoretical math angle instead of a brute force computational approach and there is some consensus that RSA-2048 may be broken in the next few years. A transition to Elliptic Curve Cryptography (ECC) is underway and RSA has never been approved for Suite-A or Suite-B encryption which might lead one to believe that the NSA has known about the weakness of RSA for a long time.
- aa0 13y agoI see, makes sense - it is easy to multiply big nums together but insane to factor the bignums out of them. You explained it more succinctly than I've ever understood it, thanks a ton!