Bitcoin's technology - protocol and cryptography - has a proven, high level of security, and Bitcoin's network is probably the world's largest distributed computing project. The biggest vulnerability in Bitcoin is the mistakes of the users themselves. Bitcoin-purse files that store the necessary private keys can be accidentally deleted, lost or stolen. This is very similar to physical cash stored in electronic form. Fortunately, users can use the best security practices to protect their money or use services that provide a good level of protection and insurance against theft and loss.