The blockchain technology backing cryptocurrency is inherently secure, thanks to the decentralized — and public — nature of distributed ledger technology and the encryption process every transaction undergoes.
Although transaction fees don’t accrue to sellers, miners are permitted to prioritize fee-loaded transactions ahead of fee-free transactions when creating new blocks, even if the fee-free transactions came first in time.

WASHINGTON (AP) — The Justice Department has recovered most of a multimillion-dollar ransom payment made to hackers after a cyberattack that caused the operator of the nation's largest fuel pipeline to halt its operations last month, officials said Monday.
One example is the negative correlation that occurs between Ethereum and its associated factors around June 2016 (left facing arrows at the top and just left of the horizontal middle of the Ethereum scalograms). During this time interval, one of the most well-known applications at the time, the DAO, built on top of the Ethereum environment, was hacked. It can be seen that all factors are negatively correlated in the short term with the price during this time interval. As a result of the uncertainty generated by the hack, price dropped sharply, but activity on social media and interest increased (causing the negative correlation). The negative relationship can be seen during the 2–4 day band for all factors.