CompTIA Security+ — All Questions

Many privacy laws require that when personal data is breached, affected individuals and regulators must be informed within a defined timeframe. What is this obligation called?

• a.A breach notification requirement✓
• b.A memorandum of understanding stating the non-binding intent of two parties
• c.A right-to-audit clause
• d.A service level agreement

Breach notification requirements obligate organizations to inform affected individuals and often regulators within set deadlines after a data breach. Laws like GDPR and various state statutes impose these duties. Timely notification is both a legal and trust obligation.

A team rates risks as high, medium, or low based on expert judgment of likelihood and impact rather than precise dollar figures. Which analysis approach is this?

• a.Qualitative analysis✓
• b.A BIA
• c.Quantitative analysis
• d.A penetration test

Qualitative risk analysis uses descriptive ratings like high, medium, and low based on judgment when precise figures are unavailable. It is faster and more subjective than quantitative analysis. Many programs combine both for a fuller picture.

When an employee leaves, the organization follows a checklist to disable accounts, revoke access, and collect equipment. Which governance element defines these steps?

• a.A standard
• b.A guideline
• c.A high-level policy stating only a general commitment to protecting security
• d.An offboarding procedure✓

An offboarding procedure gives the step-by-step actions for securely separating an employee, such as disabling accounts and recovering assets. Procedures translate policy into concrete, repeatable steps. Prompt offboarding prevents lingering access from becoming a threat.

Before a penetration test begins, both parties sign a document defining the scope, permitted techniques, timing, and systems that are off-limits. What is this document?

• a.An SLA document
• b.A BIA report
• c.A non-disclosure agreement
• d.The rules of engagement✓

Rules of engagement define the scope, boundaries, permitted methods, and timing of a penetration test, protecting both parties. They prevent misunderstandings and unintended damage. Clear authorization also keeps the testing legal.

An organization takes reasonable, ongoing steps a prudent entity would take to protect its assets and meet its obligations. Which concept describes this ongoing reasonable action?

• a.Risk acceptance
• b.Separation of duties, which splits a sensitive task among several people to deter any fraud
• c.Due diligence
• d.Due care✓

Due care is the ongoing exercise of reasonable precautions a prudent organization would take, while due diligence is the investigation and research that informs decisions. Both are used to demonstrate responsible governance. Together they help defend against negligence claims.

The security team periodically compiles key risks, their status, and trends into a summary for executives to support decision-making. This activity is called:

• a.Penetration testing
• b.Risk reporting✓
• c.Data masking
• d.Change management

Risk reporting communicates the current risk landscape, status, and trends to stakeholders such as executives and the board. It enables informed, risk-based decisions and resource allocation. Effective reporting is clear, timely, and tied to business impact.

A bank must protect customers' nonpublic personal financial information and explain its information-sharing practices. Which US law imposes these requirements?

• a.HIPAA, which governs the protection of protected health information
• b.GDPR
• c.The Gramm-Leach-Bliley Act✓
• d.PCI DSS

The Gramm-Leach-Bliley Act (GLBA) requires financial institutions to protect customers' nonpublic personal information and disclose their information-sharing practices. It includes a Safeguards Rule for security controls. It applies specifically to financial services firms.

Why should security policies include a defined schedule for periodic review and revision?

• a.So they stay aligned with evolving threats, technology, regulations, and business needs✓
• b.Because review permanently eliminates all residual risk associated with the policy's subject
• c.Because policies that are reviewed can never afterward be challenged in any court of law
• d.So that employees are no longer required to acknowledge or follow them once they are reviewed

Policies must be reviewed and revised on a schedule so they remain effective as threats, technology, laws, and the business change. Stale policies create gaps and compliance issues. Governance includes ownership and a defined revision cadence.

When selecting a firm to perform an independent security audit, why should the auditor have no financial stake in the outcome?

• a.Because regulators require every external auditor to also sell remediation products to clients
• b.To avoid a conflict of interest that could compromise the audit's objectivity✓
• c.Because a financial stake would make the audit finish faster and cost the client much less
• d.Because auditors with a financial stake are legally required to work at no cost to the client

An auditor with a financial stake in the outcome has a conflict of interest that can bias findings and undermine trust in the results. Independence is essential to a credible, objective assessment. Vendor selection should screen for such conflicts.

To reduce manual effort and errors, an organization implements tools that continuously collect evidence and generate compliance status reports automatically. Which benefit does this automation primarily provide?

• a.It eliminates any need for human oversight of the compliance program from that point going forward
• b.More consistent, timely, and accurate monitoring of compliance status✓
• c.It provides a guarantee that the organization can never experience any future data breach at all
• d.It permanently removes the organization from the scope of every applicable regulation it faces

Automating compliance evidence collection and reporting improves consistency, timeliness, and accuracy while reducing manual burden. It supports continuous rather than point-in-time compliance visibility. Human oversight is still required to interpret and act on results.

A bank requires customers to enter a password and then approve a push notification on their enrolled phone before accessing their account. Which authentication factors are being combined?

• a.Two separate instances of something you know, which does not truly raise assurance
• b.Something you know and something you have✓
• c.Something you are and somewhere you are, tied to a physical biometric location
• d.Something you have and something you do, based on continuous behavioral analysis

The password is knowledge (something you know) and the enrolled phone is possession (something you have), so two distinct factor categories are combined. Genuine multifactor authentication requires categories that fail independently, so stealing one does not defeat the other. Two passwords would still be a single category and add little assurance.

An organization deploys single sign-on so employees authenticate once to reach many applications. What is the primary security trade-off administrators must plan for?

• a.A compromised SSO credential can unlock every connected application at once✓
• b.Encryption of network traffic between the applications is automatically disabled by design
• c.Users are forced to memorize a separate, complex password for every individual application they use
• d.Applications can no longer share any authentication information between one another

SSO concentrates risk because one authentication grants access to many systems, so a stolen SSO credential becomes a master key. That is why SSO should be paired with strong MFA and session controls. The convenience of one login is exactly what raises the stakes if it is compromised.

A user logs into a partner's cloud application using their own company credentials, and the company's identity system vouches for them. In this federated setup, what role does the company's identity system play?

• a.Certificate authority that signs the TLS certificate presented by the application
• b.Service provider, which hosts the partner application and stores its user data
• c.Relying party that consumes the assertion and makes the final resource decision
• d.Identity provider that authenticates the user and issues assertions✓

In federation the identity provider (IdP) authenticates the user and issues a signed assertion, while the partner acts as the service provider or relying party that trusts it. This lets users access external apps without those apps ever handling company passwords. Distinguishing the IdP from the SP is central to understanding SAML and OIDC flows.

A photo-printing website asks to access a user's cloud photo library without ever seeing the user's cloud password, using a delegated access token. Which framework is being used?

• a.OAuth 2.0✓
• b.Kerberos
• c.RADIUS
• d.SAML browser single sign-on

OAuth 2.0 is an authorization framework that issues scoped access tokens so one service can act on a user's behalf without receiving their password. It delegates access, not identity, which is why scopes limit what the token can do. Limiting scope and token lifetime is key to using it safely.

A developer needs not just delegated access but also verified identity information about the user, returned in a signed ID token. Which protocol layered on OAuth 2.0 provides this?

• a.802.1X
• b.LDAP
• c.TACACS+, which separates authentication, authorization, and accounting for device admin
• d.OpenID Connect✓

OpenID Connect adds an identity layer on top of OAuth 2.0, returning a signed ID token that proves who the user is. OAuth alone handles authorization, so OIDC is what supplies authenticated identity. This distinction is why OIDC is used for modern web and mobile sign-in.

In a Windows domain, a workstation presents a time-stamped ticket to reach a file server without re-entering a password. Why does Kerberos rely on tightly synchronized clocks across the domain?

• a.Because tickets are stored permanently and never expire once they are issued to a host
• b.Because time stamps limit ticket validity and help prevent replay attacks✓
• c.Because the key distribution center encrypts all file contents using the workstation clock
• d.Because domain controllers bill each user for the exact number of seconds of access used

Kerberos tickets carry time stamps and short lifetimes, so synchronized clocks let servers reject stale or replayed tickets. If clocks drift too far apart, valid tickets are refused and stale ones might be accepted. This is why time synchronization is a hard requirement in Kerberos realms.

An administrator notices directory queries and bind credentials are traveling in cleartext over port 389. Which change encrypts this directory traffic?

• a.Disable anonymous binds but keep the existing plaintext connection on port 389
• b.Move the directory server into the screened subnet that faces the public internet
• c.Use LDAPS, wrapping LDAP in TLS on port 636✓
• d.Switch the directory to broadcast its queries over UDP so that lookups complete faster

LDAPS encapsulates LDAP inside TLS, typically on port 636, encrypting both queries and bind credentials in transit. Cleartext LDAP exposes directory passwords to any on-path attacker. Encrypting the channel, not just restricting binds, is what protects the credentials.

A network team wants centralized administrator login to routers with the ability to authorize individual commands and log each one separately. Which protocol best fits because it separates authentication, authorization, and accounting?

• a.TACACS+✓
• b.SAML
• c.RADIUS
• d.Kerberos

TACACS+ separates authentication, authorization, and accounting into independent functions, enabling per-command authorization and detailed logging for device administration. RADIUS merges authentication and authorization, giving less granular command control. This separation is why TACACS+ is favored for network device admin.

To reduce standing administrative rights, a company grants elevated access only for a short approved window and records the session. Which control is this?

• a.Mandatory access control, enforcing sensitivity labels assigned by a central authority
• b.Privileged access management with just-in-time elevation✓
• c.Discretionary access control, letting each resource owner set their own file permissions
• d.Single sign-on, which authenticates the user once for access to many applications

Privileged access management with just-in-time elevation removes always-on admin rights, granting them briefly on request and recording the activity. This shrinks the window an attacker can abuse stolen admin credentials. Time-boxing and session recording are what distinguish it from static privileged accounts.

A DevOps team stops hardcoding database passwords in scripts and instead retrieves them at runtime from a centralized secrets manager that rotates them automatically. What risk does this primarily reduce?

• a.The risk of exposed, static, long-lived credentials embedded directly in source code✓
• b.The risk that end users will choose weak passphrases for their own personal accounts
• c.The risk that TLS certificates will silently expire and break client connections later
• d.The risk of denial-of-service caused by too many simultaneous inbound connections

A secrets manager keeps credentials out of code and rotates them, so a leaked repository or old backup no longer hands attackers valid passwords. Hardcoded secrets are long-lived and hard to rotate once exposed. Centralized, rotating retrieval directly addresses that exposure.

An access system evaluates the user's department, the device's health, the time of day, and data sensitivity before allowing a request. Which access control model is described?

• a.Discretionary access control, where the owner of the resource decides access
• b.Attribute-based access control✓
• c.Rule-based access control
• d.Role-based access control

Attribute-based access control (ABAC) makes decisions from multiple attributes of the user, device, resource, and context, enabling fine-grained, dynamic policies. Role-based control keys only on job role and is less context-aware. Combining many attributes is the defining trait of ABAC.

A cloud platform blocks logins from unmanaged devices and requires MFA when a sign-in comes from an unusual country. What is this adaptive approach called?

• a.Implicit trust, which grants access automatically to anyone already inside the network
• b.Full-disk encryption, which protects data stored locally on the endpoint while at rest
• c.Conditional access based on risk and device posture✓
• d.Static access lists that never change regardless of context or the current risk signals

Conditional access evaluates signals such as device compliance, location, and risk to decide whether and how to grant access, stepping up authentication when risk rises. It embodies zero-trust thinking by never trusting a session on network location alone. Adapting requirements to context is its central idea.

A security team tuning a fingerprint reader wants the setting where the false acceptance rate equals the false rejection rate, used to compare device accuracy. What is this point called?

• a.Crossover error rate✓
• b.The annualized rate of occurrence
• c.The single loss expectancy
• d.Mean time to repair

The crossover error rate (CER) is where false acceptance and false rejection rates are equal, giving a single number to compare biometric accuracy. A lower CER means a more accurate sensor overall. It lets teams tune sensitivity while understanding the balance between wrongly admitting and wrongly rejecting users.

During an audit, several active accounts belong to employees who left the company months ago. Which identity lifecycle failure does this reveal?

• a.Failure to deprovision accounts promptly at offboarding✓
• b.Improper encryption of the directory database in which the user accounts are stored
• c.Excessive multifactor prompts that cause users to approve push requests carelessly
• d.Weak password complexity requirements enforced at the moment of initial account creation

Leftover active accounts show a breakdown in deprovisioning, the offboarding step that disables access when someone leaves. Orphaned accounts are prime targets because no one monitors them. Tying account deactivation to HR offboarding prevents this gap.

An engineer needs to encrypt large volumes of stored data quickly using a single shared key and selects AES. Why is a symmetric cipher like AES preferred here over an asymmetric one?

• a.Because asymmetric ciphers are technically unable to encrypt data of any size at all
• b.Because AES automatically distributes its own keys with no coordination required at all
• c.Because symmetric encryption uniquely provides non-repudiation of the original sender
• d.Because symmetric ciphers are much faster for bulk data encryption✓

Symmetric ciphers such as AES are far faster and less compute-intensive than asymmetric algorithms, making them ideal for encrypting large data volumes. Asymmetric crypto is slow and typically used only to exchange keys or sign. Speed on bulk data is the reason AES is chosen here.

A protocol encrypts a real-time voice stream one bit or byte at a time as it is generated, rather than in fixed 128-bit blocks. Which cipher type suits this continuous data best?

• a.An RSA cipher
• b.A stream cipher✓
• c.A one-way hash
• d.A block cipher in ECB mode

A stream cipher encrypts data continuously, bit or byte at a time, which fits real-time streams like voice where data arrives incrementally. Block ciphers work on fixed-size chunks and can add latency or padding. Matching the cipher to the data flow is the key idea here.

Two parties who have never met need to agree on a shared secret over an open network without ever transmitting the secret itself. Which mechanism enables this?

• a.A certificate revocation list
• b.A hash function
• c.Diffie-Hellman key exchange✓
• d.Symmetric AES encryption using a key shared beforehand

Diffie-Hellman lets two parties derive a shared secret over an untrusted channel without sending the secret, using public exchanges and private values. It solves the bootstrapping problem of symmetric keys. This is why it underpins secure session establishment in protocols like TLS.

A security architect wants assurance that if a server's long-term private key is later stolen, past recorded TLS sessions still cannot be decrypted. Which property, achieved with ephemeral keys, provides this?

• a.Perfect forward secrecy✓
• b.Non-repudiation
• c.Certificate pinning, which hardcodes an expected certificate into the client
• d.Key escrow

Perfect forward secrecy uses ephemeral, per-session keys that are discarded, so compromising the long-term key does not expose previously recorded sessions. Each session's secret is independent of the server's static key. This limits the blast radius of a future key theft.

A mobile device team wants strong asymmetric security with smaller keys and lower power use than RSA. Which algorithm family meets this need?

• a.SHA-3
• b.AES
• c.Elliptic curve cryptography✓
• d.RSA with 4096-bit keys, maximizing key length regardless of battery life

Elliptic curve cryptography achieves comparable security to RSA with much smaller keys, reducing computation, memory, and power draw. This efficiency suits constrained mobile and IoT devices. Smaller keys for equivalent strength are ECC's defining advantage.

To make stored password hashes far more expensive to crack, a developer chooses an algorithm deliberately designed to be slow and memory-hard, such as Argon2 or bcrypt. What is this technique called?

• a.Tokenization
• b.Certificate stapling
• c.Steganography
• d.Key stretching✓

Key stretching applies deliberately slow, resource-intensive functions like bcrypt, PBKDF2, or Argon2 so each password guess costs an attacker significant time. This blunts brute-force and dictionary attacks against stolen hashes. Intentional slowness is exactly the point of the technique.

An API includes a keyed hash with each message so the receiver can confirm both that the content is unchanged and that it came from a party sharing the secret key. What is this construct?

• a.A digital certificate
• b.An AES ciphertext block
• c.A hash
• d.An HMAC✓

A hash-based message authentication code (HMAC) combines a shared secret key with a hash, providing both integrity and authenticity. A plain hash detects change but not who produced it. Mixing in the secret key is what proves the message came from a key holder.

Before a certificate authority can issue a TLS certificate, an admin generates a request containing the server's public key and identifying details, signed by the matching private key. What is this request called?

• a.A certificate signing request✓
• b.A certificate revocation list, which lists certificates no longer trusted
• c.A key escrow deposit
• d.An OCSP response

A certificate signing request (CSR) packages the public key and identity information and is signed by the corresponding private key to prove key ownership. The CA validates it before issuing a signed certificate. The private key itself never leaves the requester, which is why only the CSR is sent.

To limit exposure of its most trusted key, an organization keeps its root CA offline and issues day-to-day certificates from a subordinate CA. What is the main security benefit?

• a.Clients can skip verifying the certificate chain entirely because the root is offline
• b.The intermediate CA removes the need to ever renew certificates before they expire
• c.The offline root key stays protected while the intermediate handles routine issuance✓
• d.Certificates no longer need to be validated against any revocation source by clients

Keeping the root CA offline protects the most critical key, while an intermediate CA does everyday signing. If an intermediate is compromised it can be revoked without destroying the entire trust hierarchy. This tiered design contains damage and preserves the root's integrity.

A high-traffic site wants clients to learn a certificate's revocation status without each client separately querying the CA, reducing latency and privacy leakage. Which approach fits?

• a.Pinning
• b.Distributing a full certificate revocation list to every browser hourly
• c.Disabling revocation checking
• d.OCSP stapling✓

OCSP stapling has the server periodically fetch a signed revocation status and attach it to the TLS handshake, so clients get proof without contacting the CA themselves. This cuts latency and stops the CA from seeing which clients visit. The server, not each client, does the checking.

A mobile banking app hardcodes the expected server certificate so that even a fraudulent but validly-signed certificate from another CA is rejected. This defense is called:

• a.Certificate pinning✓
• b.Key stretching
• c.Wildcard certification
• d.Cross-certification

Certificate pinning embeds the expected certificate or key in the app so it refuses any other certificate, even one a CA would normally trust. This blocks man-in-the-middle attacks using rogue but validly issued certificates. The trade-off is that pinned certificates must be updated before they change.

A company wants one certificate to secure store.example.com, mail.example.com, and any other host under example.com. Which certificate type covers all subdomains at one level?

• a.A code-signing certificate
• b.An extended validation certificate
• c.A root certificate
• d.A wildcard certificate✓

A wildcard certificate uses a name like *.example.com to secure any single-level subdomain, simplifying management. The convenience comes with risk, since one compromised private key affects every covered host. Understanding its scope and shared-key risk is the exam point.

An internal test server presents a certificate that no public CA vouches for, so browsers warn users. Why does a self-signed certificate trigger this warning?

• a.Because no trusted third party has verified the certificate's authenticity✓
• b.Because self-signed certificates are hardcoded to expire within twenty-four hours only
• c.Because self-signed certificates always use a weaker cipher than CA-issued certificates
• d.Because the private key is automatically published alongside the certificate's public key

A self-signed certificate is not vouched for by any CA in the browser's trust store, so the client cannot confirm the server's identity and warns the user. The encryption strength can be identical; the issue is missing third-party validation. Trust chaining, not cipher strength, is what is absent.

So encrypted data is not permanently lost when an employee leaves or forgets a passphrase, an organization stores a protected recovery copy of decryption keys with a trusted custodian. This practice is:

• a.Certificate pinning
• b.Perfect forward secrecy
• c.Salting
• d.Key escrow✓

Key escrow stores a recoverable copy of cryptographic keys with a trusted party so data can be recovered if the original key is lost. It supports business continuity but also creates a high-value target that must be tightly controlled. The recovery copy is the essence of escrow.

Anticipating that today's algorithms may weaken over time, an architect designs systems so cryptographic algorithms can be swapped with minimal disruption. This design goal is called:

• a.Steganography
• b.Cryptographic agility✓
• c.Homomorphic encryption
• d.Ephemeral keying

Cryptographic agility is designing systems so algorithms and key sizes can be replaced as standards evolve or weaknesses emerge. It matters because ciphers age and quantum computing threatens some today. Building in swap-ability avoids costly rip-and-replace later.

Before publishing a software update, a vendor signs the installer with its private key so users can verify the code's origin and that it was not modified. Which control is this?

• a.Code signing✓
• b.A certificate revocation list
• c.Hashing
• d.Full-disk encryption

Code signing attaches a digital signature to software so users can confirm the publisher and detect tampering before running it. A broken or missing signature signals modification or an untrusted source. This provides integrity and authenticity for distributed code.

An executive needs to send email that is both encrypted and digitally signed using certificate-based keys. Which standard provides this for email messages?

• a.DKIM signing
• b.DMARC
• c.SPF
• d.S/MIME✓

S/MIME uses certificates and key pairs to encrypt and digitally sign individual email messages, giving confidentiality, integrity, and authentication at the message level. SPF, DKIM, and DMARC authenticate the sending domain but do not encrypt the message body. Per-message signing and encryption are what S/MIME adds.

A team discovers two different files produce the same MD5 digest, letting an attacker substitute a malicious file undetected. What weakness does this demonstrate?

• a.A hash collision in a broken algorithm✓
• b.A downgrade attack forcing an older and weaker TLS protocol version
• c.A replay attack
• d.A brute-force attack

A hash collision occurs when two different inputs produce the same digest, and MD5 and SHA-1 are broken because collisions can be engineered. This lets an attacker swap a benign file for a malicious one with a matching hash. Using collision-resistant algorithms like SHA-256 prevents it.

Two users choose the identical password, yet their stored hashes differ because a unique random value was added to each before hashing. What is that per-password value?

• a.A salt✓
• b.A pepper
• c.A nonce
• d.An IV

A salt is a unique random value added to each password before hashing, so identical passwords yield different hashes and precomputed rainbow tables fail. A pepper, by contrast, is a single secret applied to all passwords. Per-password uniqueness is what distinguishes a salt.

TLS encrypts the bulk session with a fast symmetric key but uses the server's public key only to protect that symmetric key during setup. Combining both this way is known as:

• a.Steganography
• b.Hybrid encryption using a digital envelope✓
• c.An HMAC over the encrypted stream
• d.Key escrow, which deposits session keys with a third-party custodian

Hybrid encryption uses fast symmetric encryption for the data and slower asymmetric encryption only to protect the symmetric key, a pattern called a digital envelope. This captures the speed of symmetric crypto and the key-distribution ease of asymmetric crypto. TLS relies on exactly this combination.

To stop attackers from feeding forged DNS responses to clients, an organization signs its DNS records so resolvers can cryptographically verify their authenticity. Which extension provides this?

• a.A web application firewall
• b.A VPN
• c.Network address translation
• d.DNSSEC✓

DNSSEC adds digital signatures to DNS records so resolvers can verify responses are authentic and unmodified, defeating cache poisoning and spoofing. It provides origin authentication and integrity but not confidentiality. Signed records are what let a resolver trust an answer.

A site-to-site VPN must both encrypt payloads and authenticate them between two gateways, protecting the entire original IP packets. Which IPsec component and mode apply?

• a.The TLS record protocol
• b.GRE alone
• c.ESP in tunnel mode✓
• d.AH in transport mode

Encapsulating Security Payload (ESP) provides both encryption and authentication, and tunnel mode wraps the entire original IP packet, which suits gateway-to-gateway VPNs. AH authenticates but does not encrypt, and transport mode leaves original headers exposed. ESP plus tunnel mode meets both requirements.

A security review flags that servers still accept SSL 3.0 and TLS 1.0, enabling downgrade attacks. What is the recommended remediation?

• a.Enable every available protocol version so the widest possible range of clients can connect
• b.Replace the certificates with self-signed ones to sidestep protocol version negotiation
• c.Disable obsolete protocols and require TLS 1.2 or 1.3✓
• d.Rely only on the certificate's validity and ignore which protocol version was negotiated

Downgrade attacks force use of older, weaker protocols, so disabling SSL and early TLS and requiring TLS 1.2 or 1.3 removes the vulnerable options. Certificate validity is unrelated to the negotiated protocol version. Eliminating weak versions is what closes the downgrade path.

Network monitoring currently uses a version of SNMP that sends community strings in cleartext. Which version adds authentication and encryption for management traffic?

• a.Syslog over UDP
• b.SNMPv1
• c.SNMPv3✓
• d.NetFlow

SNMPv3 adds authentication and encryption, protecting management credentials and data that earlier versions sent in cleartext. Versions 1 and 2c rely on community strings exposed to sniffing. Upgrading to v3 secures the management plane.

A VoIP deployment must keep call audio confidential and protected from tampering in transit. Which protocol secures the media stream?

• a.SMTP over TLS
• b.SIP
• c.SNMP
• d.SRTP✓

Secure Real-time Transport Protocol (SRTP) encrypts and authenticates the audio and video media stream in VoIP, protecting call content. SIP handles signaling and needs its own protection, such as SIP over TLS. Securing the media, not just signaling, is SRTP's role.

A domain owner wants receiving servers to reject spoofed mail claiming to come from their domain and to receive reports on abuse. Which policy layer builds on SPF and DKIM to enforce this?

• a.OCSP
• b.S/MIME
• c.DMARC✓
• d.TLS

DMARC builds on SPF and DKIM, telling receivers how to handle messages that fail alignment and providing aggregate reports on abuse. It is what turns sender authentication into an enforceable, reportable policy. SPF and DKIM verify; DMARC decides and reports.