Cryptocurrency Security
The security of cryptocurrencies is two part. The first part comes from the difficulty in finding hash set intersections, a task done by miners. The second and more likely of the two cases is a “51%” attack“. In this scenario, a miner who has the mining power of more than 51% of the network, can take control of the global blockchain ledger and generate an alternative block-chain. Even at this point the attacker is limited to what he can do. The attacker could reverse his own transactions or block other transactions.

Cryptocurrencies are also less susceptible to seizure by law enforcement or having transaction holds placed on them from acquirers such as Paypal. All cryptocurrencies are pseudo-anonymous, and some coins have added features to create true anonymity.