randpass

Generates passwords. One, a million, or a continuous byte stream.

Installation | Examples | Interactive Mode | Technical Details

Examples

# Basic
randpass                                 # Interactive TUI
randpass -l 20                           # 20-character password
randpass -l 16 -b                        # Copy to clipboard

# Character sets
randpass -l 32 --hex                     # Hex only (0-9, a-f)
randpass -l 20 --no-special              # Alphanumeric only
randpass -l 20 --special '_-'            # Custom special characters

# Bulk
randpass -l 32 -n 1000000 -o out.txt     # Million passwords, progress bar, interruptible
randpass -l 24 -n 1000 -o passwords.txt

# Raw bytes
randpass --bytes -n 1G -o random.bin     # 1GB to file
randpass --bytes -n 100M | xxd | head    # 100MB to stdout
randpass --bytes | dieharder -a -g 200   # Infinite stream for testing

# Command mode (save defaults)
randpass -c set -l 20 -n 5               # Save flags; future `randpass` uses them
randpass -c                              # Show saved command
randpass -c unset                        # Clear saved command

Run randpass -h for all options.

Interactive Mode

Run without arguments for the TUI.

#	Setting	Description
1	Password Length	Characters per password
2	View Seed Strings	Show the character pool before/after shuffle
3	Number of Passwords	How many to generate per run
4	Special Character List	Which symbols to include
5-8	Density Multipliers	Weight character classes. Setting lowercase to 2 adds a-z twice to the pool, making them 2× more likely
9	To terminal	Print passwords to stdout
10	Output file path	Write passwords to file. Defaults to `rand_pass.txt` if path ends with `/` or `.`
11	Skip Countdown	Bypass 10s delay before large batches (>100)
12	Command on start	Default flags for `randpass` (see Command Mode)
13	Entropy Source	`rdtsc` (hardware) or `/dev/urandom`

Settings persist to ~/.config/randpass/settings.

Installation

Cargo

cargo install randpass

Pre-built Packages

Download from GitHub Releases:

Platform	Package
Debian/Ubuntu	`randpass_x.x.x_amd64.deb`
Fedora/RHEL	`randpass-x.x.x-1.x86_64.rpm`
Arch Linux	`PKGBUILD`
Linux (generic)	`randpass-vx.x.x-x86_64-linux.tar.gz`
AppImage	`randpass-vx.x.x-x86_64.AppImage`

# Debian/Ubuntu
sudo dpkg -i randpass_*.deb

# Fedora/RHEL
sudo rpm -i randpass-*.rpm

# Arch Linux
makepkg -si

# Generic (extract and copy)
tar xzf randpass-*.tar.gz
cp randpass-*/randpass ~/.local/bin/

Build from Source

cargo build --release
cp target/release/randpass ~/.local/bin/

Technical Details

PRNG

Uses CPU timestamp counters (rdtsc on x86_64, cntvct_el0 on ARM) mixed with a 10,000-prime table and SplitMix64 finalizer. With -u, uses a 32MB /dev/urandom pool with background refresh instead.

Entropy Source → rotate(17) × prime[idx] ⊕ entropy → SplitMix64 → Output

Password Generation

Character pool built from enabled classes with configurable density multipliers (e.g., lowercase_density: 2 makes lowercase 2× more likely). Pool is shuffled, then characters selected via PRNG indices.

Security

Passwords zeroized after use
Direct write_all() I/O avoids format string allocations
Terminal state restored on signals
Settings file stores configuration only, never passwords
Pipe-safe: escape codes suppressed when stdout is not a TTY

Validation

Suite	Tests	HW (rdtsc)	urandom
TestU01 BigCrush	160	159 pass, 1 weak	158 pass, 2 weak
Dieharder	114	112 pass, 2 weak	112 pass, 2 weak

Full results in rng/results/.

Platforms

Arch	Hardware Source
x86_64	`rdtsc`
aarch64	`cntvct_el0`
arm	`pmccntr64`
Other	`/dev/urandom` fallback

License

MIT OR Apache-2.0

randpass 0.3.0