[Cryptography] sibyl attacks

[Henry Baker]

At 03:33 PM 9/16/2015, Ray Dillinger wrote:
>But why wouldn't the ad broker engage in a sibyl attack?

I love the term "sibyl attack":

https://en.wikipedia.org/wiki/Sybil_attack

The stock market has had a similar attack for many, many years: the (naked) "bear raid".

https://en.wikipedia.org/wiki/Bear_raid

In a legitimate bear raid, a company's stock is sold short with *borrowed* stock.  Borrowing stock requires that the borrowee provide permission, and the borrowee is usually compensated with a small amount of interest.

However, the SEC has never really punished broker-dealers who ignore the *borrowed stock* requirement, so a broker-dealer can sell an almost unlimited amount of stock, and since the rules for quickly "settling" are also routinely ignored, such broker-dealer can remain truly "naked" for months or even years.

Small companies have complained bitterly for years about this abuse, but without any real progress.

NASDAQ claims to be implementing a block-chain system for keeping track of stock; one hopes that such a system will finally stop these illegal "bear raids".