Data is prone to various attacks. One of these attacks includes message authentication. This threat arises when the user does not have any information about the originator of the message. Message authentication can be achieved using cryptographic methods, which further make use of keys.
Authentication Requirements:
- Revelation: It means releasing the content of the message to someone who does not have an appropriate cryptographic key.
- Analysis of Traffic: Determination of the pattern of traffic through the duration of connection and frequency of connections between different parties.
- Deception: Adding out-of-context messages from a fraudulent source into a communication network. This will lead to mistrust between the parties communicating and may also cause loss of critical data.
- Modification in the Content: Changing the content of a message. This includes inserting new information or deleting/changing the existing one.
- Modification in the sequence: Changing the order of messages between parties. This includes insertion, deletion, and reordering of messages.
- Modification in the Timings: This includes replay and delay of messages sent between different parties. This way, session tracking is also disrupted.
- Source Refusal: When the source denies being the originator of a message.
- Destination refusal: When the receiver of the message denies the reception.
Message Authentication Functions:
Message authentication and digital signature mechanisms operate on two functional levels:
- Lower level: At this level, there is a need for a function that produces an authenticator, which is the value that will further help in the authentication of a message.
- Higher-level: The lower-level function is used here to help receivers verify the authenticity of messages.
Message authentication functions fall into three classes:
- Message encryption: protects data from interception during transmission, such as in MITM attacks, by converting plaintext into ciphertext. It includes symmetric encryption, which uses a shared secret key between sender and receiver to ensure confidentiality and authenticity, and public key encryption, which uses key pairs to provide confidentiality, while authentication is achieved using the private key.
- Message authentication code (MAC): Generates authentication value using message and shared secret key to verify sender identity, ensures data integrity by detecting modifications and confirming authenticity during communication.
- Hash function: A hash function converts input of any length into fixed-length output known as message digest, used to verify data integrity by comparing hash values, providing one-way transformation that prevents reverse computation.
Prevention Steps of Network Attacks:
- Message Confidentiality: To prevent the messages from being revealed, care must be taken during the transmission of messages. For this, the message should be encrypted before it is sent over the network.
- Message Authentication: Message authentication ensures secure communication by verifying sender identity and preventing traffic manipulation, using shared secret codes and digital signatures for authentication, and involving trusted third party to validate authenticity of communicating entities.
- Digital Signatures: Digital signatures provide help against a majority of these issues. With the help of digital signatures, content, sequence, and timing of the messages can be easily monitored. Moreover, it also prevents denial of message transmission by the source.
- Combination of protocols with Digital Signatures: This is needed to deal with the denial of messages received. Here, the use of digital signature is not sufficient and it additionally needs protocols to support its monitoring.