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Insider Brief
- In a public report on PQC preparedness, the GAO found that none of 24 major federal agencies reviewed fully addressed all three preparation practices for protecting systems against future quantum computing threats.
- The review identified incomplete inventories of vulnerable systems, inadequate migration cost assessments and no testing of post-quantum cryptography in agency environments.
- GAO made 89 recommendations to strengthen preparation, including addressing expertise gaps, establishing inventory and funding assessment processes, and developing testing plans.
None of the 24 major federal agencies reviewed by the Government Accountability Office fully completed the preparation practices it assessed for protecting government systems against future quantum computing attacks.
That’s according to the GAO’s recently released 2026 report , which is the public version of a 2025 report, although portions of the original 2025 report remain withheld because federal agencies deemed the information sensitive.
According to the new GAO public report, the gaps covered identifying systems that use vulnerable cryptography, estimating the cost of replacing it and testing alternatives designed to withstand quantum attacks. GAO found that incomplete inventories, shortages of cryptography expertise and inadequate planning left agencies poorly positioned to manage the transition. These are three essential tasks for PQC preparation.
Only one agency fully addressed the necessary activities for developing a prioritized inventory of vulnerable systems. None fully assessed the funding needed to transition their priority systems, and none tested post-quantum cryptography in their own environments, according to the report.
The findings point to a governmentwide preparation problem that extends beyond choosing new security technology. Agencies need to establish what they operate, determine which systems require attention first and develop repeatable processes for estimating costs and testing replacements.
GAO analysts were not facing a shortage of ideas to address the situation, however, making 89 recommendations in its earlier 2025 sensitive report, including calls to establish and implement processes for developing cryptographic inventories and identifying migration funding.
The October 2026 public version makes no additional recommendations. The publication preserves the earlier report’s objectives and audit methodology. New updates may show that the deficiencies identified during the earlier review were addressed and offer evidence of heightened preparation.
Real Threat, Necessary Preparation
Today’s quantum computers cannot break the cryptography at issue in the report. A sufficiently powerful future machine, however, could undermine certain methods federal agencies use to protect communications and verify the identities of users, devices and software.
Post-quantum cryptography uses mathematical methods designed to resist those attacks. Agencies can implement it on conventional computers, but moving to it requires changes across software, hardware and services.
GAO identified two principal risks from a quantum computer capable of breaking vulnerable cryptography. First, an attacker could compromise the systems that establish trust. Recovering a secret cryptographic key could allow an attacker to forge digital credentials, impersonate a privileged user or make malicious software appear legitimate.
Second, an attacker could collect encrypted communications today and retain them until a sufficiently powerful quantum computer becomes available — a technique typically referred to as “harvest now, decrypt later”. Information that must remain confidential for many years could therefore face exposure even before such a machine exists.
That possibility makes the preparation gaps consequential now, according to GAO. Agencies must identify systems carrying information that will remain sensitive well into the future, rather than base their work solely on predictions about when quantum computers might become capable of an attack.
The timeline remains uncertain, as the GAO cited a December 2024 survey of 32 industry experts who placed the probability of a “cryptographically relevant quantum computer” being developed by 2040 above 50%. Estimates vary because researchers still must improve the reliability of quantum computing components and develop supporting technology.
The report also cautions against assuming that a future quantum computer could immediately unlock vast amounts of stolen information. Recovering individual keys could take substantial time and resources. Nevertheless, the exposure of even a small amount of important information could seriously affect federal operations.
Step-by-Step
The report indicated that agencies take the first step of developing and annually updating an inventory of priority systems that use vulnerable cryptography.
Those inventories should cover systems essential to agency missions, systems whose compromise could cause severe harm, information expected to remain sensitive in 2035 and systems that control access using vulnerable public-key cryptography.
GAO found that one agency had not developed an inventory, while 22 had inventories that did not fully account for all priority systems. Only one fully addressed the activity.
Missing systems was one problem, but the GAO identified that missing or incorrect technical information was another problem.
Several inventories lacked information about vulnerable cryptographic methods, software packages, operating systems or hosting arrangements. Some incorrectly listed symmetric cryptography — which uses the same secret key to encrypt and decrypt information — as vulnerable to the quantum threat assessed in the report.
For a closer accuracy check, GAO examined documentation for 15 systems at six selected agencies. None of those six fully supported the accuracy of the cryptographic information or system characteristics examined. Those detailed findings apply to the selected agencies and systems, rather than every federal system.
Workforce and process weaknesses helped explain the gaps. Eighteen agencies reported lacking expertise in cryptography and related inventory development, and they had not developed plans to address those shortages. Six agencies had taken steps to educate or train their workforces.
Only one agency had documented an inventory maintenance process. The other 23 lacked documented procedures for consistently collecting and maintaining the information. Five agencies used automated tools to identify and verify inventory data. Nineteen did not.
Automation was recommended as an aid, rather than required by policy, and officials cautioned that tools alone could not produce complete inventories. Still, GAO found that agencies needed stronger processes and expertise to understand their exposure.
The Cost and Testing Gaps
Incomplete inventories also weakened agencies’ cost estimates. Twenty-one agencies developed funding assessments, but none fully addressed the activity of identifying funding for all vulnerable priority systems and ensuring the assessment’s accuracy. The remaining three did not develop assessments.
All 21 agencies with assessments acknowledged that their data were not fully accurate. As mentioned, some cited a lack of vendor prices, reliable tools or trained personnel. Only one of the 24 agencies documented a process for assessing migration funding.
The Office of Management and Budget used agency assessments to provide Congress with an approximately $7.1 billion governmentwide estimate for migrating priority systems or replacing older systems that could not support post-quantum cryptography.
Officials from OMB and the Office of the National Cyber Director said those assessments were intended to provide rough estimates for senior decision-makers. They were not expected to supply precise budget figures while vendors were still incorporating the new cryptographic standards into products.
GAO acknowledged those constraints but concluded that agencies needed documented processes to improve future estimates and reduce the risk of unexpected costs.
Testing was similarly limited with only one agency conducting market research to identify potential vendor implementations for testing, although it did not test them in its environment. The other 23 did not address either activity.
Sixteen agencies said it was too early to identify candidates and conduct testing because vendors were still incorporating the algorithms into their products.
A disagreement over expectations did stand out. National Cyber Director officials said agency testing was encouraged rather than explicitly required and that many agencies lacked the resources or expertise to conduct it.
GAO maintained that early testing was practical and important for identifying older systems and custom software that might need replacement. It pointed to available open-source tools for research and prototypes, while officials cautioned that those tools alone could not meet government deployment and oversight needs.
What Agencies Need to Do
The report’s corrective approach begins with building reliable inventories and establishing processes to keep them current.
Agencies need to address gaps in workforce expertise, document responsibilities for collecting and checking system information and prioritize systems according to their importance and the sensitivity of their data.They also need processes for developing and updating funding assessments. Better inventories would give those assessments a stronger foundation, while vendor information could help refine estimates as products become available.
Testing plans should identify suitable environments and opportunities to work with vendors. The aim is to discover compatibility problems early, including systems that cannot support the new cryptography and must be replaced.
GAO warned that agencies could not wait for inventories to mature gradually or for further guidance before addressing the weaknesses it identified.
Of the 23 agencies receiving recommendations in the sensitive report, 12 agreed, two partially agreed, seven neither agreed nor disagreed, one disagreed with three of its four recommendations and one did not respond.
The public report notes some subsequent activity. The Social Security Administration said it had updated its process for collecting cryptographic information, while the Department of Homeland Security described its continued commitment to quantum readiness.