It became a national holiday in 1948, but it has been a day of celebration in Japan since ancient times. The fifth day of the fifth month was traditionally called Tango no Sekku and was a festival for boys. Girls have their own festival, called Hina Matsuri (Doll Festival), held on the third day of the third month.
Expressions full disk encryption (FDE) or whole disk encryption signify that everything on disk is encrypted, but the master boot record (MBR), or similar area of a bootable disk, with code that starts the operating system loading sequence, is not encrypted.
Private Key/Public Key: The encryption using a private key/public key pair ensures that the data can be encrypted by one key but can only be decrypted by the other key pair. This is sometime hard to understand, but believe me it works.