🛡️ Desktop-2FA

A secure, offline two-factor authentication (2FA) manager for desktop environments. Built with Python, featuring strong encryption and no cloud dependencies.

🌐 Landing Page: desktop-2fa.org

Adding a new TOTP entry interactively

Generating a TOTP code for an entry

Renaming an entry with duplicate detection

Viewing version info and listing all entries

pip install desktop-2fa

Verify installation:

python -c "import desktop_2fa; print(desktop_2fa.__version__)"
# Output: 0.9.0

# Initialize a new vault
d2fa vault init

# Add a new TOTP token
d2fa add GitHub GitHub JBSWY3DPEHPK3PXP

# Or add a provisioning URI (quote it so the shell preserves '&')
d2fa add "otpauth://totp/Example:alice?secret=JBSWY3DPEHPK3PXP&issuer=Example&algorithm=SHA256&digits=8&period=60"

# List all entries
d2fa list

# Generate a code
d2fa code GitHub

The vault is stored by default at ~/.desktop-2fa/vault. Select a different file for any command with the global --vault option, or set DESKTOP_2FA_VAULT to choose one by default. An explicit --vault takes precedence over the environment variable; without either, the default remains ~/.desktop-2fa/vault.

# Use a separate vault for this command
d2fa --vault ./development-vault list

# Show the currently selected vault path
d2fa --vault ./development-vault vault path

# Launch the early Textual UI prototype with that vault
d2fa --vault ./development-vault ui

URI-based add preserves algorithm, digits and period; omitted parameters default to SHA1, 6 digits and 30 seconds. Labels are percent-decoded, and an issuer query parameter must agree with any issuer prefix. Unsupported or contradictory provisioning data exits with status 6 before vault access. Interactive add also accepts a URI at the issuer prompt and skips the separate secret prompt. The URI label supplies the account name.

The Textual UI is at an early prototype stage. It prompts for the vault password unless one is supplied with --password or --password-file, and supports listing entries, generating codes, and copying codes to the clipboard. It does not support entry management or create a missing vault.

# Provide password via command line
d2fa --password mypassphrase add GitHub GitHub JBSWY3DPEHPK3PXP

# Provide password via file
d2fa --password-file /path/to/passphrase.txt add GitHub GitHub JBSWY3DPEHPK3PXP

The vault is an encrypted storage file located by default at ~/.desktop-2fa/vault; use --vault or DESKTOP_2FA_VAULT to select another path. Vault files must be regular files no larger than 10 MiB.

The current loader supports vault format version 1. Future releases are not guaranteed to support every older format. Before upgrading, create an encrypted backup and store it securely.

Desktop-2FA 0.9.0 changes the public Python API: Vault.save() and Vault.load() require an explicit, non-empty password. Vaults created by earlier Python API versions with no password must be opened and re-saved with a non-empty password using the previous release before upgrading. CLI and Textual UI flows already require a non-empty password.

d2fa backup

New TOTP secrets use shared Base32 rules: ASCII case and spaces are accepted, correct trailing padding is optional, and empty decoded keys are refused before vault access. New records use canonical uppercase padded text with identical decoded bytes. Existing secret text is preserved on load/save. Legacy empty or historically admitted Unicode-folded secrets remain listable but cannot generate codes; code reports invalid_secret with status 6. See the explicit repair procedure.

When a CLI command that creates or updates entries requires a vault and none exists:

1. The CLI prompts for a new password (interactive mode) or requires --password/--password-file (non-interactive mode)
2. An empty encrypted vault is created
3. A confirmation message is always printed: Vault created at <path>

The Textual UI does not create a missing vault; it displays the vault-loading error instead.

When a command requires a vault and it exists:

1. The CLI prompts for the existing password (interactive mode) or requires credentials (non-interactive mode)
2. The vault is decrypted and loaded
3. Authentication failure exits with status 2; other failures use the shared exit-status contract and never report success.

The code and remove commands resolve names case-sensitively. An exact account_name match takes precedence over another entry's issuer. Without an exact account match, a unique issuer match is accepted for compatibility. Multiple exact account matches or multiple fallback issuer matches are rejected with an Ambiguous entry error (exit status 6); the vault is left unchanged. code --json reports entry_ambiguous. Python Vault.get_entry() and Vault.remove_entry(), and the public code/removal helpers, use the same rule; ambiguous lookups raise desktop_2fa.vault.AmbiguousEntry, a ValueError subclass.

The rename command uses the same exact-account-name/unique-issuer rule and rejects an occupied destination account name before mutation. Ambiguity without an explicit selector, invalid selectors and occupied destinations exit with status 6. Both account name and issuer are updated; renaming a uniquely named entry to itself is allowed and still updates its issuer.

For legacy duplicates, run d2fa list --indices, then d2fa rename OLD NEW --index N using a displayed one-based entry number. The selected entry must match OLD at the account-name/issuer tier that ordinary lookup would use. Indices describe the current list order, not permanent IDs; list again after adding/removing entries and avoid concurrent vault edits. See duplicate recovery.

The --vault option takes precedence over DESKTOP_2FA_VAULT. When neither is provided, Desktop-2FA uses ~/.desktop-2fa/vault. The code command also supports --json, --raw, --quiet, --copy, and --copy-only; --force is available on vault initialization and import commands.

The vault uses:

• AES-256-GCM for authenticated encryption
• Argon2id for key derivation (time_cost=4, memory_cost=128MiB, parallelism=2)
• zxcvbn for password strength evaluation
• Versioned header to identify the vault format

Every command that accesses vault contents requires password authentication. Path and version queries do not access vault contents. No session-based access.

Desktop-2FA uses zxcvbn to evaluate password strength when creating or changing vault passwords:

• Score 0-2 (Weak): Easily guessable passwords (e.g., "password123")
• Score 3-4 (Strong): Resistant to common attacks (recommended)

Examples:

• ❌ Weak: password, 123456, qwerty, admin2024
• ✅ Strong: Battery-Horse-Staple-Correct, Mountain@River*2024, MySecureVault#42

Configuration (~/.config/d2fa/config.toml):

[security]
# Require strong passwords (score >= 3)
reject_weak_passwords = false  # warn but allow | true: reject weak passwords

When reject_weak_passwords = false:

• Weak passwords trigger a yellow warning
• User is prompted to confirm continuation
• Password acceptance is non-blocking

When reject_weak_passwords = true:

• Weak passwords are rejected immediately
• Command exits with error
• User must choose a stronger password

Backward Compatibility: If you have min_password_entropy set in your config (legacy option), it is recognized and treated as equivalent to requiring zxcvbn score >= 3.

Version 0.8.2 added bounded vault loading and atomic saves; version 0.8.3 added the early Textual UI prototype; version 0.9.0 requires explicit, non-empty passwords in the public Python vault API:

• Empty passwords are immediately rejected with a clear error message
• Permission errors are distinguished from missing vault files
• Vault loading accepts only regular files and reads at most 10 MiB
• Vault saves use unique temporary files and atomic replacement
• No Python stack traces are shown to users
• User-friendly error messages for filesystem permission issues
• Modular design separates CLI and core cryptographic components for enhanced security boundaries
• zxcvbn-based password strength evaluation

pytest tests/              # Run all tests
pytest --cov=src/desktop_2fa  # Run with coverage

src/desktop_2fa/
├── app/           # Application components
├── cli/           # Command-line interface
├── crypto/        # Encryption utilities
├── totp/          # TOTP generation
├── ui_textual/    # Early Textual UI prototype
├── vault/         # Vault management
└── utils/         # Utilities

Apache License 2.0. See LICENSE file.

Łukasz Perek

desktop‑2fa is supported through the Kilo OSS Sponsorship Program.

For questions or support, contact us at contact@desktop-2fa.org

Desktop‑2FA is an independent open‑source tool built with a focus on autonomy, transparency, and offline security. If you find it useful and want to support ongoing development, you can do so through the platforms below:

• Ko‑fi: https://ko-fi.com/lukaszperek
• Buy Me a Coffee: https://buymeacoffee.com/lukaszperek
• AirTM: https://airtm.me/lukper