Encryption is the translation of data into a secret code. Encryption is considered to be the most effective way to achieve data security. To read an encrypted file, you must have access to a secret key or password (used for encryption) that enables you to decrypt it. Decryption is the encryption's reverse action.
Encryption is based on Encryption Algorithms - you can see these algorithms as a process capable of translating data into a secret code.
AES - Short for Advanced Encryption Standard, is a symmetric 128-bit block (SafeBit uses 256-bit version) data encryption technique developed by Belgian cryptographers Joan Daemen and Vincent Rijmen. AES works at multiple network layers simultaneously.
The Symmetric key algorithms are designed to be very fast and have a large number of possible keys. AES 256-bit (and 128-bit) encryption algorithm offers excellent secrecy; once data is encrypted with a given key, there is no fast way to decrypt the data without possessing the same key.