State v. Levie
The main purpose of encryption is to change any data to a humanly unreadable form. Nowadays, encryption is seen as one of the key solutions to prevent the unauthorized disclosure of information. 
Companies and governmental entities have been spending time and money implementing ways to fight cybercrime and increase awareness between internet users and general public with the purpose to reduce the occurrence of crimes such as Identity theft. 
Mainly, one can say that encryption is about privacy. The right to a "safety zone" and privacy exists in the First and Fourth Amendment rights in the USA where a remarkable and recent privacy-based law has been approved, the Gramm-Leach-Bliley Act. In Europe the Lisbon Treaty describes the protection of fundamental data as fundamental human right. 
While achieving privacy through the use of encryption seems to provide everyone with answers to decrease the disclosure of personal information, it benefits the possibility to conceal from authorities acts of terrorism, child pornography and others.
The use of encryption tools is becoming more and more disseminated; states are starting to make a crime "to use encryption". States like Illinois in USA are creating specific laws to handle this matter : "A person shall not knowingly use or attempt to use encryption, directly or indirectly, to:
Data Encryption Standard
DES is the archetypal block cipher—an algorithm that takes a fixed-length string of plaintext bits and transforms it through a series of complicated operations into another ciphertext bitstring of the same length. In the case of DES, the block size is 64 bits. DES also uses a key to customize the transformation, so that decryption can supposedly only be performed by those who know the particular key used to encrypt. The key ostensibly consists of 64 bits; however, only 56 of these are actually used by the algorithm. Eight bits are used solely for checking parity, and are thereafter discarded. Hence the effective key length is 56 bits.