File Formats
Necron Vault Manager supports multiple encrypted file formats. This page explains each format, when it's used, and how they differ.
Format Summary
| Format | Extension | Authenticated | Status |
|---|---|---|---|
| NCV3 | .ncv3 or .ncrn |
✅ Yes — tamper-protected | Current standard |
| NCV2 | .ncrn |
✅ Yes — tamper-protected | Current (vault objects) |
| OTP1 | .ncrn |
❌ No | Legacy (decrypt only) |
| NECN | .ncrn |
❌ No | Legacy (decrypt only) |
Tip
For new encryptions, always use NCV3 (the default). It provides the strongest security with modern authenticated encryption. Legacy formats are supported for decryption only.
NCV3 — The Current Standard
NCV3 is the modern encrypted file format used by Necron Vault Manager. It uses authenticated encryption, meaning any tampering with the encrypted file is detected during decryption.
Key Features
- Authenticated encryption — any tampering is detected during decryption
- Streaming support — files are encrypted in chunks, supporting files of any size without needing the whole file in memory
- Efficient key usage — each file uses only a tiny portion of your dongle's key material
- Anti-rename protection — detects if someone renames the encrypted file on disk
When NCV3 Is Used
- Quick Encrypt operations (default)
- All new standalone file encryptions
NCV2 — Vault Storage Format
NCV2 is used for files stored inside vaults. It combines encrypted filenames with encrypted content and an integrity check.
Key Differences from NCV3
| Feature | NCV3 | NCV2 |
|---|---|---|
| Primary use | Standalone files | Vault storage |
| Filename | Plaintext + .ncv3 |
Encrypted token + .ncrn |
| Key efficiency | Very efficient (tiny key usage per file) | Uses more key material (proportional to file size) |
| Integrity | Per-chunk tamper detection | Whole-file tamper detection |
When NCV2 Is Used
- Files imported into a vault
- Vault browser file operations (add files, add folder, drag-and-drop)
Legacy Formats (OTP1, NECN)
OTP1 and NECN are older encryption formats from earlier versions of the software. They use a simpler encryption method without tamper protection.
Warning
Legacy formats do not provide tamper detection. An attacker could modify the encrypted file without it being noticed. NCV3 and NCV2 prevent this entirely.
Decryption Support
Legacy files are fully supported for decryption in current versions. However, they are no longer offered as encryption options. All new encryptions use NCV3 or NCV2.
Tip
If you have files in OTP1 or NECN format, you can re-encrypt them with NCV3 to upgrade to authenticated encryption. Decrypt the file with your dongle, then re-encrypt with NCV3.
Format Detection
When decrypting, Necron Vault Manager automatically detects the format. You never need to specify the format manually — the app handles it transparently. You can even mix formats in a single batch decrypt operation.
Comparison Table
| Feature | NCV3 | NCV2 | OTP1 / NECN |
|---|---|---|---|
| Tamper-protected | ✅ Yes | ✅ Yes | ❌ No |
| Large file support | ✅ Streaming chunks | ✅ Whole-file | ✅ Whole-file |
| Filename encryption | Optional | ✅ Always | ❌ No |
| Anti-rename protection | ✅ Yes | ✅ Yes | ❌ No |
| Key efficiency | ✅ Very efficient | ⚠️ Proportional to file size | ⚠️ Proportional to file size |
| Status | ✅ Current standard | ✅ Current (vault objects) | 📦 Legacy (decrypt only) |