Which security mechanism is specifically designed to ensure that a message is not altered in transit?

Which security mechanism is specifically designed to ensure that a message is not altered in transit?

• A. Encryption
• B. Digital Signature
• C. Checksum
• D. Message Integrity Check

Answer: (B)

The correct choice is based on the fundamental purpose of a digital signature, which is to provide assurance that a message has not been altered during transmission. A digital signature uses cryptographic techniques to create a unique fingerprint of a message. When a sender signs a document with their private key, a recipient can verify the signature with the sender's public key, ensuring the integrity and authenticity of the message. This verification process is crucial because it not only confirms that the message originated from the purported sender (authenticity) but also checks if the content of the message has remained unchanged since it was signed, thereby ensuring that any unauthorized alterations are detectable. While other choices relate to different aspects of security, they do not specifically address the dual purpose of ensuring message integrity and authenticity. For instance, encryption primarily focuses on confidentiality, ensuring that only authorized parties can read the message, but it doesn’t provide a means to verify whether the message was altered. Similarly, checksums and message integrity checks are used to detect changes in data but do not provide the same level of assurance regarding the identity of the sender and the authenticity of the message as a digital signature does.

The correct choice is based on the fundamental purpose of a digital signature, which is to provide assurance that a message has not been altered during transmission. A digital signature uses cryptographic techniques to create a unique fingerprint of a message. When a sender signs a document with their private key, a recipient can verify the signature with the sender's public key, ensuring the integrity and authenticity of the message.

This verification process is crucial because it not only confirms that the message originated from the purported sender (authenticity) but also checks if the content of the message has remained unchanged since it was signed, thereby ensuring that any unauthorized alterations are detectable.

While other choices relate to different aspects of security, they do not specifically address the dual purpose of ensuring message integrity and authenticity. For instance, encryption primarily focuses on confidentiality, ensuring that only authorized parties can read the message, but it doesn’t provide a means to verify whether the message was altered. Similarly, checksums and message integrity checks are used to detect changes in data but do not provide the same level of assurance regarding the identity of the sender and the authenticity of the message as a digital signature does.