[BE-111] Hardcoded fallback JWT secrets in AuthService and JwtStrategy

[yusuftomilola]

Overview

AuthService.generateAccessToken()/generateRefreshToken() and JwtStrategy's constructor all read the signing secret via configService.get<string>('JWT_SECRET', 'secretKey') / 'refreshSecretKey' (backend/src/auth/auth.service.ts, backend/src/auth/strategies/jwt.strategy.ts). If JWT_SECRET/JWT_REFRESH_SECRET is ever unset — a misconfigured environment, not just local dev — the app silently signs and verifies tokens with these literal strings from the source code, which anyone who has read the repo can forge.

Tasks

• Fail fast at startup (in main.ts or a ConfigModule validation schema) if JWT_SECRET or JWT_REFRESH_SECRET is unset or shorter than a safe minimum length.
• Remove the 'secretKey'/'refreshSecretKey' literal fallbacks from auth.service.ts and jwt.strategy.ts.
• Document the required env vars in backend/.env.example with a comment that there is no default.
• Add a unit test asserting the app fails to boot when the secret is missing.

Acceptance Criteria

• Booting the app with JWT_SECRET unset throws instead of falling back to a guessable string.
• No source file contains a literal fallback secret.

Notes for Contributors

Comment below to be assigned.

[amossamuel851-tech]

@amossamuel851-tech has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello, I am a fullstack developer with years of experience building web3 and web3 applications, I have reviewed the issue and the project, please assign me this issue.

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[onyemaechiezekiel9]

@onyemaechiezekiel9 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

Hello I have gone through the issue and I would love to work on this swiftly

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[OladipupuHussein7]

@OladipupuHussein7 has applied to work on this issue as part of the Stellar Wave Program's 8th wave.

I can take this bug on and track down the root cause.

AuthService.generateAccessToken()/generateRefreshToken() and JwtStrategy's constructor all read the signing secret via configService.get('JWT_SECRET', 'secretKey') / 'refreshSecretKey' (backend/src/auth/auth.service.ts, backend/src/auth/strategies/jwt.

I'll make sure each of these is covered:

• Booting the app with JWT_SECRET unset throws instead of falling back to a guessable string
• No source file contains a literal fallback secret
• Notes for Contributors
• Comment below to be assigned

I'll keep the change focused and match the existing code conventions.

ℹ️ Repo Maintainers: To accept this application, review their application or assign @OladipupuHussein7 to this issue.

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Congratulations, @OladipupuHussein7! 🎉 Your application was accepted by the repo's maintainers, and the issue is due on August 31, 2026.

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[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox!

@OladipupuHussein7's PR #1363 was approved and merged by @yusuftomilola.

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👏 Great work, @OladipupuHussein7! Keep contributing to DistinctCodes.

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