Flash memory is not a reliable medium for archives. Especially when there is no regular power. I have personal experience with usb flash drive not powered for weeks - one file became corrupted . (Read more here: Archiving private keys - TLDR version. ) You should always back up on paper and other mediums. Flash memory is prone to failure if it is not powered for weeks or more and if there are ionizing radiation When you write your precious private keys you should use technologies like Parchive and ZFS . And make several copies of your files. It's OK if you use your USB flash drive for another backup, but don't rely on it! Always back up on DVDs (even small files!), paper and online (after encryption with CPU and RAM intensive key derivative function like scrypt). Here is example of using the scrypt utility: $ sudo apt-get install scrypt $ scrypt enc -M 1073741824 -t 200 secret.txt encrypted.scrypt Do not use default values of "-M" and "-t", they are we…