An honest comparison with the common VNC implementations, as of 2026. Where a product has several modes, the table shows what it offers out of the box on Windows.
| JVNC 1.0 | TightVNC 2.x | UltraVNC 1.4 | TigerVNC 1.x | RealVNC Connect (commercial) | |
|---|---|---|---|---|---|
| Password | PBKDF2-SHA256 verifier, salt+nonce challenge (password never sent, no length limit) | Classic VNC auth: DES challenge, 8-character maximum, weak | VNC auth (8 chars) or MS-Logon (Windows accounts) | VNC auth, or username/password over TLS (VeNCrypt Plain) | Windows/system accounts or RealVNC account |
| Encryption | TLS 1.2/1.3 built in, self-signed cert, fingerprint pinning | None built in (needs SSH/VPN) | Optional DSM/SecureVNC plugin (AES) | VeNCrypt: TLS, anonymous or X.509 | Always on, AES-256 |
| Device certificates (mutual TLS) | Yes — server keeps an approved-client list | No | No | X.509 client certs possible with own PKI (manual) | Device authorisation via cloud |
| Second factor | TOTP (Google/Microsoft Authenticator) | No | No | No | MFA (cloud) |
| IP allow list | CIDR list | Yes | Yes | No (use firewall) | Cloud policy |
| Brute-force lockout | 5 fails → 15 min ban + 1 s delay | Basic delay after failures | Yes | Basic | Yes |
| Refuses public addresses unless device cert | Yes (default on) | No | No | No | n/a (brokered) |
| Secrets at rest | DPAPI-encrypted TOTP secret, remembered passwords | Password stored obfuscated in registry (recoverable) | Same as TightVNC lineage | Config file | Cloud |
| Works with third-party viewers | Yes — VNC Auth / VeNCrypt TLS for stock viewers (JVNC extras need the JVNC client) | Yes | Yes | Yes | No |
| Runs as Windows service / shows lock screen | No (session only) | Yes | Yes | Yes | Yes |
| Codebase / audit history | Small, new, unaudited | 20+ years, several CVEs fixed | 20+ years, several CVEs (incl. 2019–2022 memory bugs) | Actively maintained, security releases | Commercial, audited |
Where JVNC is stronger
Where the others are stronger
Bottom line: against opportunistic attack on an exposed port, a JVNC server with password + TLS + device certificate (+ TOTP) is materially harder to get into than a stock TightVNC/UltraVNC/TigerVNC install, because those either ship unencrypted with an 8-character password or need extra software to do better. Against a determined attacker targeting the implementation itself, the mature projects have the edge. In both cases the right answer is the same: put it behind a VPN and use JVNC's layers as defense in depth (see the Security Guide).
| JVNC | TightVNC | UltraVNC | TigerVNC | |
|---|---|---|---|---|
| Windows key and Win+key shortcuts (Win+R, Win+E, Win+D, Win+arrows) sent to the remote PC | Yes — the only one of these that does it: a low-level hook captures the key so your own PC does not react | No (Win key acts locally; some viewers have a "send Win" button) | Partial (menu items / scroll-lock trick) | No |
| Multi-monitor as one desktop | Yes | Yes | Yes | Yes |
| Single-monitor view / multi-head (one window per remote monitor on your monitors) | Yes / Yes | Single monitor only | Single monitor only | Single monitor only |
| Shared clipboard | Yes (text, both ways, also from stock viewers into the PC) | Yes | Yes | Yes |
| Drag-and-drop files onto the viewer | Yes | No | Yes (file transfer window) | No |
| Reverse connection (server dials the viewer) | Yes (JVNC or stock viewers in listen mode) | Yes | Yes | Yes |
| Wake-on-LAN + auto-reconnect | Yes (MAC learned automatically) | No | No | No |
| Session recording + playback | Yes (built in, .jvncrec) | No | No (third-party) | No |
| Audit log of sessions/transfers | Yes (JSON lines) | No | Log file | No |
| Printer redirection | Yes (JVNC Remote Printer → PDF on the viewer side) | No | No | No |
| Remote audio (hear the remote PC) | Yes (built in, 4:1 ADPCM) | No | No | No |
| Change-driven updates (no polling delay, ~120 fps cap) | Yes | Hook/poll driver | Mirror driver optional | Poll |
| Adaptive lossy encoding (JPEG while moving, lossless when still) | Yes (per-tile clean-up) | Tight JPEG (static quality) | Tight/Ultra | Tight JPEG |
| Scroll detection (CopyRect) | Yes (per 64-px tile, exact match) | Yes | Yes | Yes |
| Bandwidth adaptation | Yes (measured link → frame budget, pointer area first, JPEG quality) | Partial (auto quality) | Manual | Manual |
| Cursor drawn in the picture | Yes | Yes | Yes | Yes |
| File transfer, both directions, no size limit | Yes, streamed to disk; auto-accept or dialog | Yes | Yes | No (server) |
| Full-screen viewer | F11 | Yes | Yes | Yes |
| Tray server, single instance, autostart at sign-in | Yes | Service | Service | Service |
| Remembered hosts / passwords (encrypted) | Yes | Hosts | Hosts | Hosts |
| Connection profiles + clickable jvnc:// links | Yes | Yes (.vnc files) | Yes (.vnc files) | Yes (.tigervnc) |
| Stuck-drag protection on disconnect | Yes | — | — | — |
| Installer with no prerequisites | Yes (self-contained) | Yes | Yes | Yes |
| Size on disk | ~300 MB (bundled .NET runtime) | ~5 MB | ~10 MB | ~10 MB |
| Price / licence | Free, this project | Free (GPL) | Free (GPL) | Free (GPL) |