What is encrypted agility?

In simple terms, password agility refers to the ability to quickly and reliably replace password algorithms. This capability ensures that the system can respond promptly and maintain protection when faced with emerging attack methods (such as the threat posed by quantum computing).

For instance

• SHA-1 was discovered to have security flaws as early as 2005, but many systems still haven't completely phased it out.

• The 3DES encryption method was not officially phased out until 2024, despite the fact that its successor, AES, was released as early as 2001.

These cases highlight the high cost of password migration. In the absence of agility, the prolonged use of outdated algorithms may bring systemic risks.

The concept of password agility is not new. As early as 2016, NIST defined three core capabilities that a password agile system should possess:

• The equipment can select the security algorithm in real time based on its comprehensive security functions.

• It is capable of adding new password functions or algorithms to existing hardware or software to enhance security.

• Be capable of elegantly eliminating password systems that have become weak or outdated.

In the CSWP 39 white paper of 2025, password agility was further refined and examined from the perspective of the national cybersecurity strategy. The updated definition emphasizes practical system deployment and states:

Password agility refers to the ability to quickly replace or adjust the password algorithm without interrupting the system operation, so as to adapt to new security requirements and computing environments, and enhance the overall system resilience.

The white paper summarizes the pain points encountered during several historical migration processes of cryptographic algorithms, including:

• Migration period is long: For instance, the transition from 3DES to AES took 23 years, indicating that without an agile mechanism, upgrading can be extremely difficult.

• Backward compatibility and interoperability challenges: Weak algorithms often need to be retained for compatibility, which significantly delays their obsolescence;

• Continuous migration requirements: As computing capabilities increase, algorithm parameters (such as the length of RSA keys) must also be continuously enhanced - the system ultimately must migrate to post-quantum algorithms and requires long-term evolution capabilities.

• Resource and performance challenges: New algorithms - especially post-quantum algorithms - are often more resource-intensive, featuring significantly larger key and signature sizes as well as higher computational costs.

These challenges demonstrate that password agility is not merely a matter of algorithm replacement; it requires careful planning at the architectural level in advance.

1. Protocol Design: Supports negotiation and migration mechanisms
The white paper states that achieving agility at the protocol level requires support for algorithm identifiers and flexible negotiation mechanisms to avoid compatibility issues caused by hardcoded algorithms. It also emphasizes the need to protect the integrity of the negotiation process and prevent downgrade attacks.
Furthermore, NIST notes that some standard development organizations (SDOs) are exploring hybrid algorithms as a transitional solution for migrating to post-quantum cryptography. This approach combines traditional public key algorithms with post-quantum algorithms, providing redundancy during the transition period. Hybrid algorithms can be implemented through single-certificate or dual-certificate structures, and leave room for a complete migration to PQC in the future.
2. Software Architecture: Modular API Interface Design
The application should not directly invoke specific cryptographic algorithms. Instead, it should access the cryptographic services through the standardized APIs provided by the cryptographic library. In this way, updating the algorithms or policies only requires modifying the library or configuration, without affecting the application logic.
The white paper recommends adopting a modular architecture, separating the cryptographic operations from the application logic, and enabling on-demand algorithm loading and dynamic policy configuration.
3. Hardware Support: Built-in redundancy and scalability
When designing hardware devices (such as TPM, SIM cards and HSM), the algorithm's updateability should be taken into account. This includes supporting multiple hard-coded algorithms, upgradeable firmware and replaceable modules.
For safety-critical components that incorporate immutable verification logic during manufacturing (such as the code used for secure boot verification), it is crucial to select a strong password algorithm that maintains security throughout the entire device lifecycle - to avoid future trust failures.
4. Governance Strategy: Establishing an Organizational Agile Framework
To systematically manage the risks associated with password changes, NIST has proposed a Password Agility Strategic Plan, which helps organizations enhance password agility at the governance, identification, management, and execution levels. It consists of five key steps:
• Integration into Governance: Incorporate password agility into the overall cybersecurity governance framework of the organization;
• Establish an asset list: Identify and map all data assets and system components that use passwords, including software, hardware and protocols;
• Enhance tool support: Utilize management tools equipped with detection algorithms and vulnerability capabilities to achieve automatic discovery, assessment, and monitoring of password components;
• Determine migration priorities: Identify the systems with the highest risks, determine the action priorities based on business importance and potential vulnerabilities; Define performance indicators (KPIs) to track progress;
• Managing and mitigating risks: Update the algorithms in the portable system. For systems lacking agility, apply compensatory controls (such as zero-trust architecture) to manage risks.
The white paper also emphasizes that these governance actions should be integrated into the existing IT management processes and security frameworks - rather than being managed separately - in order to ensure sustainable password agility.
Meanwhile, NIST introduced the Cryptographic Agility Maturity Model (CAMM), which divides system capabilities into five levels (0-4), providing organizations with a reference for self-assessment and improvement.

The evolution of cryptographic algorithms is inevitable. The real question is: Do you have the resilience to stay in sync? From protocols to hardware, from software to organizational strategies, cryptographic agility is becoming a fundamental capability of modern digital infrastructure. This white paper from NIST provides a clear roadmap and actionable guidance for the industry. As the critical window period for the widespread adoption of post-quantum cryptographic standards approaches, building cryptographic agility is not only a preparation for the future but also a protection for the present.
As a leading provider of intelligent security technologies and products, Watchdata is deeply committed to innovation in the fields of cryptography, security chips, and identity authentication. We closely monitor global cryptographic standardization efforts - including those of NIST, ISO, and IETF - and actively promote the implementation of cryptographic agile architectures in sectors such as finance, telecommunications, and government. Follow us to gain more insights into cutting-edge technologies and practical solutions.