1) Irreversible: After confirmation, a transaction can‘t be reversed. By nobody. And nobody means nobody. Not you, not your bank, not the president of the United States, not Satoshi, not your miner. Nobody. If you send money, you send it. Period. No one can help you, if you sent your funds to a scammer or if a hacker stole them from your computer. There is no safety net.
比特币与莱特币都采用了区块链技术，且都有51%攻击的问题。它们采用区块链技术，所有历史记录按照时间先后顺序，打包成一个个单独的区块，再把这些单独的区块链接在一起形成一个总账本  。这些区块内除了包含交易记录外，还包含新发行的莱特币和交易的手续费，这两笔钱支付给挖矿的矿工作为酬劳。无论谁挖到该区块，那么该区块内含有的新发行的莱特币和交易的手续费这两笔钱都归挖到者，以鼓励矿工积极参与结算。区块链技术容易产生51%攻击的问题：无论任何组织甚至个人，只要掌控某一种基于区块链原理的虚拟货币的全部运算能力的51%，这个人或组织就能够任意操纵该虚拟货币的所有交易。如果区块链只认运算能力最大者，谁的运算能力最大，谁就能抢到下一个区块，如果某个个人或组织掌控了全部运算能力的51%，那就意味着没人比他运算能力更强，故而他就可以随意操纵。所以，对于基于区块链原理的虚拟货币，参与挖矿的越多就越健壮，运算能力越分散就越健壮；挖坑者越少越脆弱，运算能力越集中就越脆弱，矿池越集中也就越脆弱  。
Litecoin was one of the first cryptocurrencies after Bitcoin and tagged as the silver to the digital gold bitcoin. Faster than bitcoin, with a larger amount of token and a new mining algorithm, Litecoin was a real innovation, perfectly tailored to be the smaller brother of bitcoin. “It facilitated the emerge of several other cryptocurrencies which used its codebase but made it, even more, lighter“. Examples are Dogecoin or Feathercoin.
Depending on a jurisdiction you live in, once you’ve made a profit or a loss investing in cryptocurrencies, you might need to include it in your tax report. In terms of taxation, cryptocurrencies are treated very differently from country to country. In the US, the Internal Revenue Service ruled that Bitcoins and other digital currencies are to be taxed as property, not currency. For investors, this means that accrued long-term gains and losses from cryptocurrency trading are taxed at each investor’s applicable capital gains rate, which stands at a maximum of 15 percent.
Many people believe that cryptocurrencies are the hottest investment opportunity currently available. Indeed, there are many stories of people becoming millionaires through their Bitcoin investments. Bitcoin is the most recognizable digital currency to date, and just last year one BTC was valued at $800. In November 2017, the price of one Bitcoin exceeded $7,000.