曾经在香港一家茶餐厅亲眼目睹：衣冠楚楚的白人夫妇，结账时颠倒黑白，说自己给了100美金，要求其余的用港币找零。收银小弟不慌不忙，直接说调监控，引得其他食客也来看热闹。老白男有一丝不耐烦：you know what,just keep the change.小弟摇手指表示拒绝，视频调出，镜头正对收银，小弟收到钱后，双手扯平纸币，前伸展示给夫妇看，嘴里同时报：“收您100文”，赫然是一张100块的港币… source
BY 豆瓣精选
Bitcoin is a decentralized digital currency that you can buy, sell and exchange directly, without an intermediary like a bank. Bitcoin’s creator, Satoshi Nakamoto, originally described the need for “an electronic payment system based on cryptographic proof instead of trust.” Each and every Bitcoin transaction that’s ever been made exists on a public ledger accessible to everyone, making transactions hard to reverse and difficult to fake. That’s by design: Core to their decentralized nature, Bitcoins aren’t backed by the government or any issuing institution, and there’s nothing to guarantee their value besides the proof baked in the heart of the system. “The reason why it’s worth money is simply because we, as people, decided it has value—same as gold,” says Anton Mozgovoy, co-founder & CEO of digital financial service company Holyheld.
Telegram has no known backdoors and, even though it is come in for criticism for using proprietary encryption methods instead of open-source ones, those have yet to be compromised. While no messaging app can guarantee a 100% impermeable defense against determined attackers, Telegram is vulnerabilities are few and either theoretical or based on spoof files fooling users into actively enabling an attack.
豆瓣精选 from ms