Replay-Resistant Authentication makes sure that an attacker who captures an authentication exchange cannot simply replay it to get in. It requires replay-resistant authentication mechanisms for access to privileged and non-privileged accounts. Replay-Resistant Authentication (03.05.04) is closely tied to Multi-Factor Authentication (03.05.03), because the same modern authenticators often provide both properties. Per the NIST discussion, an authentication process resists replay if it is impractical to authenticate by recording and replaying previous authentication messages, and replay-resistant techniques include protocols that use nonces or challenges, such as time-synchronous or challenge-response one-time authenticators.
A common difficulty with this requirement is the same place they stumble with multi-factor authentication (MFA): scope. R2 required replay-resistant authentication only for network access. R3 removes the network qualifier and requires it for access to privileged and non-privileged accounts generally. The good news is that the strong authenticators that satisfy Multi-Factor Authentication typically satisfy replay resistance too, so the two are often solved together.
Where things stand for companies facing the transition from NIST 800-171 R2 to R3:
The following is reproduced verbatim from NIST 800-171 R3, requirement 03.05.04 Replay-Resistant Authentication. Only the formatting has been adjusted for readability. This is a single statement with no lettered parts:
The source control is IA-02(08) from NIST 800-53. There are no Organization-Defined Parameters (ODPs). Per the NIST discussion, replay-resistant techniques include protocols that use nonces or challenges, such as time-synchronous or challenge-response one-time authenticators. You can read the requirement directly at NIST 800-171 R3, 03.05.04 (p. 35).
None (0). Requirement 03.05.04 contains no bracketed assignment, so there is no organization-defined value to select and nothing for the DoD to specify. The requirement applies as written.
Your System Security Plan (SSP) narrative for 03.05.04 therefore records how the requirement is implemented rather than a parameter you chose.
NIST 800-171A R3 breaks 03.05.04 into two (2) determination statements, and it has no Organization-Defined Parameters (ODPs). These AOs are:
The two (2) objectives are replay-resistant authentication for privileged accounts and for non-privileged accounts, neither qualified by local or network access, so both cover all access. The full guidance on assessment methods and objects, is in NIST 800-171A R3, 03.05.04 (p. 44).
Examine: identification and authentication policy and procedures; system design documentation; system audit records; system configuration settings; list of privileged system accounts; system security plan.
Interview: personnel with system operations responsibilities; personnel with account management responsibilities; personnel with information security responsibilities; system developers; system administrators.
Test: mechanisms for supporting or implementing identification and authentication capabilities; mechanisms for supporting or implementing replay- resistance.
03.05.04 maps from NIST 800-171 R2 requirement 3.5.4 (employ replay-resistant authentication mechanisms for network access to privileged and non-privileged accounts):
Mapped against the two (2) AOs, both (2) are direct (minimal effort), with no net-new AOs and none with no mapping. As with Multi-Factor Authentication, the direct mapping hides a scope change. R2 3.5.4 applied to network access, and R3 removes the network qualifier so the requirement applies to all access to both account types. The objectives map directly, but confirm your replay-resistant mechanisms now reach local access as well.
Source Control in NIST 800-53 R5:
Secure Controls Framework (SCF) Crosswalk
Organizations running a single control set across multiple frameworks can satisfy 03.05.04 through the following SCF controls:
The crosswalks from NIST 800-171 R3 and NIST 800-171A R3 to the SCF are available at no cost through the SCF Set Theory Relationship Mapping (STRM): https://securecontrolsframework.com/start-here/set-theory-relationship-mapping-strm. The STRM also carries the relationship type for each mapping (Equal, Subset Of, Intersects With), which tells you whether an SCF control fully satisfies the requirement or only part of it. Mapping above taken from SCF 2026.3.
The following are issues teams may encounter rather than certainties. They are about scope and solving it with the right mechanisms, each of which needs documented evidence of due diligence and due care such as policies, standards, procedures, and configuration screenshots:
Reasonable objective evidence for an assessment is often subjective. The following examples of evidence to address NIST 800-171 R3 03.05.04 are sourced from the SCF Evidence Request List (ERL), available at https://securecontrolsframework.com/free-content/scf-download. These ERL artifacts are mapped to NIST 800-171 R3 03.05.04 through SCF controls. They establish a starting point for discussions on what an organization needs to have for evidence of due diligence and due care to withstand external scrutiny by an assessor or regulator.
Alongside these, keep the System Security Plan (SSP) narrative for 03.05.04.
With both AOs mapping directly, 03.05.04 is a light lift when solved alongside MFA. A realistic sequence:
How many assessment objectives does NIST 800-171 R3 03.05.04 have? NIST 800-171A R3 breaks 03.05.04 into two (2) assessment objectives. An assessor works through each one separately, so each needs its own evidence.
Which NIST 800-53 R5 control does NIST 800-171 R3 03.05.04 come from? IA-02(08).
How many Organization-Defined Parameters (ODPs) does NIST 800-171 R3 03.05.04 have? None (0). The requirement contains no bracketed assignment, so there is no organization-defined value and nothing for the DoD to specify.
Where does NIST 800-171 R3 03.05.04 sit in the NIST 800-171 R3 Kill Chain? Phase 12, Secure Baseline Configurations (SBC). The Kill Chain is a phased model for sequencing R3 implementation, and it assigns this requirement to that phase.
03.05.04 Replay-Resistant Authentication requires replay-resistant mechanisms for access to privileged and non-privileged accounts. It maps directly from R2 3.5.4, but R3 removes the network qualifier, so it now applies to all access. The recurring problem is leaving local access on replayable secrets. Use nonce or challenge-based authenticators, cover both account types across all access, and solve it together with Multi-Factor Authentication.
Authoritative sources:
Authoritative sources:
This guide reproduces U.S. Government text from NIST 800-171 R3 and NIST 800-171A R3. It is educational, not legal or assessment advice. Last reviewed: 2026-09-22.
