Dear Monero devs, please answer this stuff.
My English is not well to understand what does AnonyMint speak about. I just feel, he sheds light on possible fundamental vulnerability that says unlinkability is not compatible with longest chain rule of proof-of-work. I may mistake.
Key images are a unique property of the CryptoNote protocol that prevent double spends.
To quote gmaxwell and andytoshi, one of which is a core Bitcoin developer and the other is someone who truly understands both mathematics and cryptography:
Double-spending is prevented using a so-called "key image", a novel feature of BRS. The key image is a component of a BRS signature which is determined entirely by the private key used to produce the signature. This means that two signatures which use the same private key, i.e. which try to spend the same coin twice, will have the same key image. Thus preventing double-spending is as easy as ensuring that the same key image never appears twice. (On the other hand, the key image cannot be inverted to obtain the original private key; thus in the absense of double-spending attempts it cannot be used to deanonymize the signature.)
That is the end of this discussion, and I would suggest we not get caught up in random and nonsensical panic attacks just because someone claims a particular flaw exists when it doesn't.
