b3sum

TLDR

Calculate BLAKE3 checksum

$ b3sum [file]

Verify checksums

$ b3sum -c [checksums.b3]

Calculate from stdin

$ echo "data" | b3sum

Multiple files

$ b3sum [file1] [file2] [file3]

Generate keyed hash

$ b3sum --keyed < [keyfile] [file]

b3sum computes BLAKE3 cryptographic checksums. BLAKE3 is significantly faster than BLAKE2, MD5, SHA-1, and SHA-2, while maintaining high security. It's optimized for parallelism and can fully utilize modern CPU capabilities.
The tool provides similar interface to md5sum and sha256sum but with much better performance.

PARAMETERS

-c, --check

Verify checksums from file

--keyed

Use keyed hashing mode

--derive-key context

Key derivation mode

--length bytes

Output length (default: 32)

--num-threads n

Number of threads to use

--no-mmap

Disable memory mapping

--no-names

Omit filenames (output hash only)

FEATURES

- Extremely fast (GBs per second)
- Parallel processing
- Unlimited output length
- Tree hashing for verification
- Keyed mode for authentication
- Deterministic output

WORKFLOW

$ # Hash files
b3sum *.tar.gz > checksums.b3

# Verify
b3sum -c checksums.b3

# Hash stdin
cat largefile | b3sum

# Use multiple threads
b3sum --num-threads 8 hugefile.bin

CAVEATS

Relatively new algorithm (2020). Less widely adopted than SHA-256. Not suitable for password hashing (use argon2 instead). Requires recent software versions.

HISTORY

b3sum was released in 2020 alongside the BLAKE3 specification, created by Jack O'Connor and Samuel Neves as an evolution of BLAKE2 optimized for speed and parallelism.