Electrum, a wallet specialized in the security and export of your private keys and cold storage, is one of the many features that it has developed by a German computer engineer that can be used in the most popular operating systems, such as Windows, Mac and Linux and also has mobile devices.
Although its design is not well adapted for inexperienced people, over time it can be adapted where its reputation has also received contributions to its source code over the years, making it one of the most reliable purses in the market.