Passkeys reduce risk because they replace reusable secrets with device-bound cryptographic credentials. That design makes phishing, credential stuffing, and many telecom-based attacks far less effective. In eSignature workflows, the practical benefit is stronger assurance that the signer is using a legitimate device and that sensitive agreements are not exposed through password reuse or delivery failures.
Why passkeys change the risk profile in signing workflows
Passkeys work because they bind authentication to a device and use public key cryptography instead of reusable shared secrets. In an eSignature workflow, that materially changes the attack surface: a stolen password or one-time code can be replayed, but a passkey cannot be phished and reused in the same way. That reduces the chance that a signer is impersonated through simple credential theft.
The practical security gain is not just stronger login, but better assurance around the signing moment itself. Traditional authentication methods often depend on something a user knows or receives, which can be intercepted, forwarded, or socially engineered. Passkeys make the signing flow less dependent on vulnerable delivery channels and more dependent on possession of a legitimate device and an intact local authenticator.
What changes compared with passwords, SMS codes, and other traditional methods
Traditional methods usually introduce one or more of three weaknesses: reusable secrets, out-of-band delivery, and user-verifiable prompts that can be spoofed. Passwords and OTPs can be captured by phishing, reused across services, or intercepted through device compromise and telecom abuse. Passkeys remove the reusable secret from the equation and sharply reduce the value of phishing pages, credential stuffing, and SMS interception.
That matters in eSignature because the workflow is often time-sensitive and legally sensitive. If an attacker can gain access during the approval or signing step, they may be able to authorize agreements, redirect document routing, or impersonate the signer with a level of confidence that is hard to unwind after the fact. A passkey does not solve every fraud scenario, but it removes several common paths that attackers use to get to the signing step.
The strongest comparison is this: passwords and OTPs mostly protect against unauthorized use when the secret stays secret, while passkeys protect by making secret reuse and remote capture far less useful. The control is stronger because the authentication material never leaves the device in a form that an attacker can simply copy and replay elsewhere.
Risk and Threat Considerations
eSignature workflows are attractive targets because the attacker does not need broad system compromise, only enough access to impersonate a signer at the right moment. The main risk is identity assurance failure, where a legitimate-looking signature is produced under fraudulent control, or where account recovery and delivery channels become the real point of compromise instead of the signer’s device.
Failure mechanism: Phishing, OTP interception, SIM swap, password reuse, and account recovery abuse can let an attacker authenticate as the signer without owning the genuine device-bound credential. If the workflow still accepts weaker fallback methods, the overall assurance level is limited by the weakest permitted path.
Impact: A compromised signing event can create unauthorized obligations, contractual disputes, repudiation issues, and downstream access to related business systems if signed workflows trigger approvals, payments, or legal execution.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
NIST CSF 2.0 and CIS Controls v8 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| NIST CSF 2.0 | PR.AC — Access Control | Passkeys strengthen authentication and reduce impersonation risk in signing workflows. |
| PR.AA — Identity Management, Authentication and Access Control | The question centers on how authentication method choice changes assurance and fraud exposure. | |
| Recommendation — Enforce stronger authentication and restrict alternate access paths for signing actions. Require robust authentication for signer verification and approval workflows. | ||
| CIS Controls v8 | 6 — Access Control Management | Passkeys are an access-control hardening measure that reduces reliance on reusable secrets. |
| Recommendation — Remove weak login methods and standardize stronger signer authentication controls. | ||
Practitioner Guidance
What to verify: Treat the passkey policy as only as strong as the fallback paths. If SMS, email links, help-desk reset, or password recovery can still complete the same signing action, those paths need the same scrutiny as the passkey itself.
Decision rule: Use passkeys as the primary authentication method for signing, then narrow the permitted fallback options to the smallest set that still supports business continuity. If a signer can complete a high-value agreement through a weaker alternate route, the workflow has not really moved to passkey-grade assurance.
What practitioners underestimate: The main benefit is often not just phishing resistance, but reduced dependence on delivery infrastructure and shared secrets that fail under real-world abuse. For high-trust signing flows, that makes the authentication design part of evidentiary quality, not just access control.
Practitioner takeaway: Passkeys reduce risk most when they become the default path for signing and weaker recovery routes are tightly bounded, because the security model is only as strong as the least protected way to reach signature approval.
Related resources from NHI Mgmt Group
- Why do passkeys reduce risk for Windows logins compared with passwords and traditional MFA prompts?
- Why is it crucial to adopt new authentication methods in MCP usage?
- Why do passkeys reduce phishing risk compared with passwords?
- Why do passwordless methods reduce phishing risk more than traditional MFA?
Deepen Your Knowledge
Reviewed and updated by the NHIMG editorial team on September 17, 2026.
NHI Mgmt Group — the #1 independent authority on Non-Human Identity, IAM, and Agentic AI security. nhimg.org
