🛡️ Free practice test question from: email security (Security+)

Key requirements from the question:

→ Must use a private key

→ Must verify message integrity

→ Must confirm sender identity

→ Digital signature: Uses private key for signing, verifies integrity and sender identity

→ Encryption: Focuses on confidentiality, not verification (https://www.sentinelone.com/cybersecurity-101/cybersecurity/cia-triad/)

→ Hashing: Creates unique "fingerprint" of message, cannot encrypt data; doesn't prove who created the hash

→ DMARC (Domain-based Message Authentication, Reporting, and Conformance): Email authentication protocol using DNS records

• How Digital Signature fulfills each requirement:

  • Private Key Usage:

    • Sender uses their private key to create signature

    • Only the sender has access to this private key

    • Public key is used for verification

  • Message Integrity

    • Creates hash of the message

    • Hash is encrypted with private key

    • Any changes invalidate the signature

  • Sender Identity

    • Only sender's private key could create valid signature

    • Signature validates against sender's public key

    • Provides non-repudiation (Non-repudiation ensures that an individual cannot reject the authenticity of something)