Data security involves four aspects, namely Privacy, Authentication, Integrity and Non-Repudiation, in a word PAIN.
Privacy refers to the confidentiality of the transmitted data. More precisely, privacy is needed to ensure that the data is intelligible only to the intended recipient. Privacy can be achieved by encrypting data that can only be decrypted by authenticated recipients. There are two different categories for encrypting or decrypting data: the secret key method and the public key method. The secret key can be viewed as a lock that has exactly one key, which is used for both locking and unlocking. Therefore, both the sender and the receiver must use a key, while the sender uses the key to encrypt the data and the receiver decrypts it only with the same key. Since both sender and receiver keep the key secret, it is called a secret key. The secret key procedure takes less time to encrypt or decrypt the data since the key is usually small, which is why this method is used to encrypt or decrypt long messages. While the public key can be seen as a lock that has two keys, a public key to lock and a private key to unlock. In this method, a key that will be used to encrypt data or messages is announced to the public and another is kept secret by the recipient for decryption. It is efficient for mass communication since the number of keys needed is less than the secret key procedure.
Authentication, another aspect of data security, is subject to the authentication of the transmitted data. Assures the receiver that the message or data was sent by a true or expected sender. Authentication can be achieved by the user authorization method where the identity of the sender is verified before data is received. Like encryption/decryption, user authorization is also verified using the private key method and the public key method.
Data integrity means that the data received by the receiver is exactly identical to the data sent. No changes should occur during transmission, whether accidental or malicious. Integrity is subject to data having a complete or complete structure. Data integrity ensured by three types of integrity constraints: entity integrity, referential integrity, and domain integrity.
Non-repudiation means that the receiver must be able to prove that the received data came from a specific sender. This aspect is important from the business point of view. For example, if a customer submits a request for a product to a supplier, the supplier must be able to prove it.