Confidentiality refers to the process of protecting information from being accessed by unauthorized parties.

Achieving confidentiality

The main technique to achieve confidentiality is encryption.


Encryption is the process of converting the original representation of some information, known as plaintext, into an alternative form, known as ciphertext. The ciphertext can be converted back to the original plaintext only by specific authorized parties, and any other parties should not be able to infer anything about the plaintext by looking at the corresponding ciphertext.

For technical reasons, encryption is typically achieved through the use of a pseudo-random encryption key, where decryption is achieved through the use of the corresponding decryption key.

There are two main encryption schemes: symmetric and asymmetric.

Symmetric encryption

Symmetric encryption is the simplest kind of encryption, where there is a single key that can be used both as the encryption and decryption key, as shown in the following illustration:

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