Secure Registration Prototype (Julia)

This is a small prototype security system for user registration and login, built in Julia.

Features (assignment minimum + secure design)

• Web UI for username and password registration/login
• Password strength analysis with actionable feedback (length, character variety, entropy estimate, and common weakness checks)
• CAPTCHA using a timed math challenge
• Anti-bot PoW (proof-of-work) using a SHA-256 puzzle (defense-in-depth, slows scripted signups)
• Secure password storage using Argon2id via the system argon2 tool (with fallback to PBKDF2-HMAC-SHA256 if missing)
• Honeywords / honey-hashing style defense (stores multiple plausible password hashes; triggers breach lock on honeyword use)
• MFA (TOTP) support (RFC6238-style 6-digit codes)
• Parameterized SQL example: security audit log written to SQLite using bound parameters (via sqlite3 CLI)
• Security policies illustrated:
  • Minimum password length + minimum strength score
  • Password history (prevents reuse of the last N passwords)
  • Password expiry (forces change after N days, enforced on web login)
  • Login lockout after repeated failures
  • Basic rate limiting (token bucket) for registration/login attempts
  • CSRF protection, server-side sessions (opaque sid cookie), security headers, honeypot field, basic UA blocking
  • ML-inspired bot risk scoring (tiny neural net over interaction telemetry; prototype)
  • Step-up verification on login (CAPTCHA + PoW)

User data is stored locally in data/users.db (SQLite user database). Audit events are written to data/audit.db.

System dependencies

• Required: sqlite3 (user DB + audit DB are written via the SQLite CLI)
• Optional (recommended): argon2 (Argon2id password hashing; otherwise PBKDF2-HMAC-SHA256 is used)
• Optional: qrencode (renders QR codes for TOTP setup; without it the page shows the secret and otpauth:// URL)

Pages

• / home
• /register registration (password coach + CAPTCHA + PoW)
• /login login (CAPTCHA + PoW + adaptive risk controls)
• /mfa/setup enable/reset TOTP
• /mfa/verify verify TOTP during login
• /password/change password change (policy enforced)
• Note: when already signed in, visiting /login or /register redirects to /account.

Run

1. Ensure Julia is installed.
2. Use a local Julia package depot (keeps packages out of global user depot):
   • export JULIA_DEPOT_PATH="$PWD/.julia"
3. Install the packages
   • julia --project=. -e 'using Pkg; Pkg.resolve(); Pkg.instantiate()'
4. Quick dev run (installs deps locally and runs the server):
   • julia --project=. devserver.jl
5. Open:
   • http://127.0.0.1:8080

Least-privilege note: do not run as root; the app only needs to write to data/ and uses restrictive permissions (umask 077, data/ as 0700). Dev note: devserver.jl reads .env and will create/update it with missing values (including APP_SERVER_SECRET, APP_PEPPER, and APP_PW_TAG_KEY) so local secrets stay stable across restarts.

Configuration (env)

• APP_HOST / APP_PORT: bind address/port (defaults 127.0.0.1:8080)
• APP_SERVER_SECRET: required; used for signing short-lived tokens
• APP_PEPPER: recommended; server-side pepper mixed into password hashing
• APP_COOKIE_SECURE: set to 1 only behind HTTPS (adds cookie Secure and enables HSTS)
• APP_REQUIRE_MFA: 1 by default
• APP_POW_BITS / APP_POW_LOGIN_BITS: PoW difficulty (registration/login)
• APP_MFA_SETUP_TOKEN_TTL_SECONDS / APP_MFA_VERIFY_TOKEN_TTL_SECONDS: signed token TTLs for MFA flows
• APP_LOG_REQUESTS / APP_AUDIT_STDOUT: request logging and audit stdout logging (enabled by devserver.jl)

MFA (TOTP)

MFA is required by default (APP_REQUIRE_MFA=1).

• After register, the app renders the TOTP setup page (and on success redirects to /account).
• After login:
  • if MFA is already enabled for the user, you are redirected to /mfa/verify and then to /account on success
  • if MFA is required but not yet enabled, the app renders the setup page to complete enrollment

Dev UX note: /mfa/verify includes a short-lived signed token in the query/form so verification can still proceed if the browser drops the session cookie during redirects.

Common password list

src/Security.jl loads src/passwords/most-common-passwords.txt (≈100k entries) and penalizes those passwords heavily.

Requirements (Python-style)

See requirements-julia.txt (for familiarity only). Julia installs from Project.toml.

Files

• devserver.jl – dev runner (instantiate + seed + run server)
• src/DevTools.jl – seeding utilities
• src/Security.jl – hashing, password strength, captcha, PoW, TOTP
• src/Storage.jl – SQLite user DB (schema + users + honeywords + password history + rate limits)
• server.jl – web entry point
• src/WebServer.jl – HTTP.jl web server routes and web security controls
• src/SecureRegApp.jl – package entrypoint

Preview

Register

Login