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Decryption definition

Decryption is the process of converting previously encrypted data into information that can be read by humans and/or computers. In simpler terms, decryption is the inverse of encryption.

Encrypted data is often called ciphertext, while decrypted and readable data is known as plaintext.

Types of decryption

Depending on the type of encryption, an encrypted message or file requires a special key or keys to decrypt it.

  • Symmetric encryption uses a single key to encrypt and decrypt a message. This key is exchanged between the two communicating parties.
  • Asymmetric decryption uses one public key and one corresponding private key. The public key can be shared and used to encrypt data, but only those who know the private key can decrypt it.

Decryption examples

Encryption and decryption methods have been used throughout history to protect information from being acquired by unauthorized individuals.

Machines were introduced into cryptography during World War II. The best-known example is the Enigma, a machine used by the Germans to encrypt messages and later broken by Allied forces.

Today, encryption and decryption are the most essential elements of cyber security. Decryption helps protect such things as:

  • logins and passwords
  • files sent over the internet
  • private networks.