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:
File hosting service
Secret key encryption is sometimes referred to as zero knowledge, meaning that only the user has the encryption key needed to decrypt the data. Since data is encrypted using the secret key, identical files encrypted with different keys will be different. To be truly zero knowledge, the file hosting service must not be able to store the user's passwords or see their data even with physical access to the servers. For this reason, secret key encryption is considered the highest level of access security in cloud storage. This form of encryption is rapidly gaining popularity, with companies such as SpiderOak being entirely zero knowledge file storage and sharing.