Question

For Exercises 1-27, mark the answers true or false as follows: A. True B. False A digital signature allows the recipient to verify that the message truly originates from the stated sender.

Short answer

A. True

Step-by-step solution

Understand the Concept of a Digital Signature

A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents. It serves as a digital fingerprint and is an integral part of public key cryptography, ensuring that the message comes from a legitimate source.

Determine the Function of a Digital Signature

Digital signatures provide authentication and non-repudiation. This means they confirm that the message was indeed created by the claimed sender and that the sender cannot deny having sent the message.

Apply the Concept to the Statement

Evaluate if the statement 'A digital signature allows the recipient to verify that the message truly originates from the stated sender' is aligned with the function of digital signatures. Given that one key aspect of digital signatures is authentication of the sender, the statement supports the function.

Key concepts

Public Key Cryptography

Public key cryptography is a fundamental concept in the realm of secure digital communications. Imagine it as a lock-and-key system that relies on two keys - a public key and a private key.

• The public key is shared openly with anyone who wants to send you a secure message. It's like sharing your mailing address for others to send you letters.
• The private key is kept confidential, much like the key to your mailbox. Only you have access to the messages sent to your public key.

This cryptographic technique ensures that the message, once voluntarily locked by the sender using your public key, can only be unlocked by your private key.
This approach prevents unauthorized access, as only the holder of the paired private key - in this case, you - can decrypt the message.
Moreover, public key cryptography is extensively used in establishing digital signatures, which further solidify the security and authenticity of digital communication.

Authentication

Authentication is crucial in the digital world for confirming identities. It's all about making certain that the person or the entity you are communicating with is genuinely who they claim to be.
Digital signatures play a vital role in authentication. Here's a simple breakdown of how they do this:

• When someone signs a document digitally, they use their private key to create the signature. This marks the document uniquely.
• The recipient, using the sender's public key, can verify the signature, ensuring the document hasn’t been altered and indeed comes from the real sender.

Thus, digital signatures provide a reliable way to authenticate messages or documents.
They help in ensuring the integrity and origin of the communication, giving recipients the confidence that the message is authentic.

Non-repudiation

Non-repudiation is an integral aspect of digital security, ensuring that the sender cannot deny having sent a message.
This concept works hand-in-hand with digital signatures to prevent any party from pretending they never participated in a communication.

• When a message is digitally signed, there is a cryptographic proof linking the message to the sender's private key.
• Since only the owner of the private key could have created the signature, the sender cannot later deny sending the message.

Non-repudiation is crucial in legal and business transactions, where it must be assured that parties cannot deny their involvement.
Thus, it creates an irrefutable link between the sender and the sent message, providing assurance to the recipient that the communication is secure and accountable.