Key4C JWT HTTP REST API Service

Key4C JWT HTTP REST API Service is a cloud- based security platform designed to simplify and strengthen JWT authentication for your applications. With Key4C, no need to manage cryptographic keys on your own servers. Enjoy secure signing, rigorous token validation, improved performance, and a scalable architecture with all in one solution.

Start today and build a secure, efficient authentication system with ease.

1. Service Overview

JWT is a key part of many authentication systems, but is it being used securely? While secure by design, improper use can introduce serious risks.

  • Security vulnerabilities from improper use of JWT

  • Design flaws and resource overhead in DIY implementations

Attackers may exploit JWT flaws for forgery, token theft, or bypassing authentication altogether

2. Service Introduction

1

Easy deployment, optimized for the cloud

Delivered as SaaS in the cloud, the service reduces the burden of security updates and maintenance for fast and easy adoption

2

Minimize development and operational burdens

No complex key management or signing logic required— quick integration with reduced development and operational effort

3

Ensure top-level security

HSM-based key management brings enterprise-grade security to token-based authentication

4

Enhanced scalability and stability efficiency

Signing is handled by Key4C, while verification is distributed across application servers. This architecture scales efficiently with server load, enabling high-performance verification. The public key-based structure ensures robust tamper detection.

Are you preparing to obtain ISMS-P or CSAP certification? Designed to support HSM-based key generation, storage, and destruction, enabling compliance with encryption policies and secure key management requirements for certification. Provides high-assurance key management system without the need to generate or store keys directly.

ISMS-P certification(2.7.2 Encryption Key Management)

CSAP certification(12.3.2 Encryption Key Management)

3. Service Implementation: Before & After

Resolve JWT-related vulnerabilities with a secure, efficient architecture ensuring long-term protection of your authentication system.

3-1. Before implementation

  • Allowing signature omission(alg: none) > risks of accepting unsigned token and authentication bypass

  • Base64-encoded sensitive data > easy to decode and expose

  • JWT signing key stored on application/server > forgery risk if leaked

  • Missing expiration settings > stolen tokens usable indefinitely

  • Symmetric keys and hardcoding > entire auth system exposed if key is leaked

  • Signing and verification overhead > increased resource usage and complexity

  • Symmetric key model limits server scalability > difficulty in distributing load

3-2. After implementation

  • Enforcing signature verification > prevents tampering and ensures authentication integrity

  • Claims built in the agent > ensures claim structure consistency

  • Signing key created and stored in HSM > prevents key exposure at the source

  • Expiration settings with validation and renewal > prevents token reuse after theft

  • Asymmetric key structure > separates signing and verification, optimized performance

  • Token delivery via API > simplified process, reduced resource consumption

  • Distributed signing & verification > optimized response time and load distribution

  • Centralized key management > reduces operational burden for key rollout and renewal

4. Feature

4-1. Secure Key Generation

Easy and fast key generation and management through a web-based GUI

HSM-Based JWT Signing Key Generation with Complete Key Protection

  • Quickly generate and securely manage signing keys via the web consol.

  • Keys are generated exclusively inside the HSM, preventing any external exposure, and used only for JWT signing.

  • Asymmetric keys (private signing key and public verification key) are generated together; applications use the public key for verification.

4-2. JWT Issuance

Secure JWT Issuance and resource savings with simple Agent integration

Secure Communication via Certificate-Based Authentication

  • Agent and Key4C use mutual certificate authentication to create a secure channel, blocking man-in-the-middle attacks.

  • Signing occurs securely inside the HSM; signed JWTs are sent to the Agent.

  • Applications receive signed JWTs without handling signing keys or signing processes.

Simplified Architecture and Resource Efficiency

  • The application requests the public key from the Agent only once and uses it solely for local JWT verification. Since no additional communication is required for each JWT verification, performance is improved.

  • When generating a JWT, the original data is not transmitted to Key4C, eliminating the risk of data exposure or leakage.

  • Reliable JWT operation is possible without signing key management or signing logic, reducing development effort.

  • With public key verification available anywhere, load can be distributed effectively, lowering operational complexity.

5. Service Workflow Diagram