Decryption is a process that transforms encrypted information into its original format.
The process of encryption transforms information from its original format — called plaintext — into an unreadable format — called ciphertext — while it is being shared or transmitted.
To do this, parties to a private conversation use an encryption scheme, called an algorithm, and the keys to encrypt and decrypt messages. (Encrypted messages are called ciphertext, as algorithms are also called ciphers.)
Message recipients decrypt the information back into its original, readable format. Future messages when passed through the system are encrypted, and vice versa.
"Absent the tools for decryption, someone who intercepts our message cannot access our documents in any readable format."