Encryption

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In {{glossary("cryptography")}} , encryption is the conversion of {{glossary("plaintext")}}  into a coded text or {{glossary("ciphertext")}} . A ciphertext is intended to be unreadable by unauthorized readers.

Encryption is a cryptographic primitive: it transforms a plaintext message into a ciphertext using a cryptographic algorithm called a {{glossary("cipher")}} . Encryption in modern ciphers is performed using a specific algorithm and a secret, called the {{glossary("key")}} . Since the algorithm is often public, the key must stay secret if the encryption stays secure.

Without knowing the secret, the reverse operation, {{glossary("decryption")}} , is mathematically hard to perform. How hard depends on the security of the cryptographic algorithm chosen and evolves with the progress of {{glossary("cryptanalysis")}} .