Cryptography is a method of protecting information and communications through the use of codes that allow only the sender and receiver of a message to view its contents. In cryptography, an original message in plaintext is changed by means of an algorithm into something that is unreadable, known as ciphertext.

Cryptography In-Use

Cryptography provides confidentiality, integrity, authentication for sensitive information while it is stored (at rest), traveling across a network (in transit), and existing in memory (in use). Two main types of cryptosystems enforce confidentiality: symmetric and asymmetric cryptosystems.

Symmetric vs. Asymmetric Cryptography

Cryptography’s approach uses a secret key for both encryption and decryption. Data is changed into a format that cannot be read or interpreted by someone who does not have the key used to encrypt it during this phase. Symmetric cryptography is based on a single shared key that all parties are privy to and can utilize to encrypt and decrypt data. Asymmetric cryptography encrypts and decrypts a message using a pair of similar keys. Anybody can use a public key to encrypt a document so that only the recipient can decrypt it with their private key. A private key is only known to the party that generated it.

Cryptography’s Goals

  • Confidentiality: confidentiality means that only the intended recipient can decrypt and thus read the message.
  • Non-repudiation: non-repudiation means the sender of the message cannot backtrack and deny their reasons for sending the message.
  • Integrity: integrity is the idea that the information contained within the message cannot be tampered with while in storage or transit.
  • Authenticity: authenticity ensures that both the sender and recipient can confirm each other’s identities and the destination of the message.


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