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iscc-sum#

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A blazing-fast ISCC Data-Code and Instance-Code hashing tool built in Rust with Python bindings. Delivers 50-130x faster performance than reference implementations, processing data at over 1 GB/s.

Originally created to handle massive microscopic imaging datasets where existing tools were too slow.

Project Status#

Version 0.1.0 — Initial release for Data-Code and Instance-Code generation.

Warning

This package is under active development, and breaking changes may be released at any time. Be sure to pin to specific versions if you're using this package in a production environment.

Performance#

  • 950-1050 MB/s processing speed (vs 7-8 MB/s reference)
  • 50-130x faster than existing implementations
  • Consistent performance on multi-GB files

Ideal for large-scale data processing: microscopic imaging, video files, scientific datasets.

Installation#

Python Package#

The recommended way to install the iscc-sum CLI tool is using uv:

uv tool install iscc-sum

Note: To install uv, run: curl -LsSf https://astral.sh/uv/install.sh | sh (or see other installation methods)

Usage#

Command Line Interface#

The iscc-sum command provides checksum generation and verification functionality similar to standard tools like md5sum or sha256sum, but using ISCC (International Standard Content Code) checksums.

Basic Usage#

# Generate checksum for a file
iscc-sum document.pdf
# Output: ISCC:KACYPXW445FTYNJ3CYSXHAFJMA2HUWULUNRFE3BLHRSCXYH2XHGQY *document.pdf

# Generate checksums for multiple files
iscc-sum *.txt

# Read from standard input
echo "Hello, World!" | iscc-sum
cat document.txt | iscc-sum

Note

By default, this tool creates ISCC-CODEs of SubType WIDE, introduced for large-scale secure checksum support with data similarity matching capabilities. This SubType is not yet part of the ISO 24138:2024 standard but is supported by the latest version of the Iscc-Core reference implementation. For ISO 24138:2024 conformant ISCC-CODEs, use the --narrow flag in the CLI tool.

Checksum Verification#

# Create a checksum file
iscc-sum *.txt > checksums.txt

# Verify checksums
iscc-sum -c checksums.txt
# Output:
# file1.txt: OK
# file2.txt: OK

# Verify with quiet mode (only show failures)
iscc-sum -c -q checksums.txt

Output Formats#

# Default format (GNU style)
iscc-sum file.txt
# ISCC:KACYPXW445FTYNJ3CYSXHAFJMA2HUWULUNRFE3BLHRSCXYH2XHGQY *file.txt

# BSD-style format
iscc-sum --tag file.txt
# ISCC (file.txt) = ISCC:KACYPXW445FTYNJ3CYSXHAFJMA2HUWULUNRFE3BLHRSCXYH2XHGQY

# Narrow format (128-bit)
iscc-sum --narrow file.txt
# ISCC:KACYPXW445FTYNJ3CYSXHAFJMA2HU *file.txt

# Show component codes
iscc-sum --units file.txt
# ISCC:KACYPXW445FTYNJ3CYSXHAFJMA2HUWULUNRFE3BLHRSCXYH2XHGQY *file.txt
#   ISCC:EAAW4BQTJSTJSHAI27AJSAGMGHNUKSKRTK3E6OZ5CXUS57SWQZXJQ
#   ISCC:IABXF3ZHYL6O6PM5P2HGV677CS3RBHINZSXEJCITE3WNOTQ2CYXRA

# Process entire directory as single unit
iscc-sum --tree /path/to/project
# ISCC:KACYPXW445FTYNJ3CYSXHAFJMA2HUWULUNRFE3BLHRSCXYH2XHGQY */path/to/project/

Similarity Matching#

Find files with similar content:

# Find similar files (default threshold: 12 bits)
iscc-sum --similar *.jpg
# Output:
# photo1.jpg
#   ~8  photo2.jpg
#   ~12 photo3.jpg

# Adjust similarity threshold
iscc-sum --similar --threshold 6 *.pdf

Complete Options#

iscc-sum --help  # Show all available options

Options:
-c, --check      Read checksums from files and check them
--narrow         Generate shorter 128-bit checksums
--tag            Create a BSD-style checksum
--units          Show Data-Code and Instance-Code components
-z, --zero       End each output line with NUL
--similar        Find files with similar Data-Codes
--threshold      Hamming distance threshold for similarity (default: 12)
-t, --tree       Process directory as single unit with combined checksum
-q, --quiet      Don't print OK for each verified file
--status         Don't output anything, exit code shows success
-w, --warn       Warn about improperly formatted lines
--strict         Exit non-zero for improperly formatted lines

Python API#

Quick Start#

Generate ISCC-SUM codes for files:

>>> from iscc_sum import code_iscc_sum
>>> 
>>> # Generate extended ISCC-SUM for a file
>>> result = code_iscc_sum("LICENSE", wide=True)
>>> result.iscc
'ISCC:K4AA2G6UMXGFJAO6ZOMIFZIYO6LYMOBT7Q6JDI3Z75IJWQY5WH372QA'
>>> result.datahash
'1e203833fc3c91a379ff509b431db1f7fd40dea69a6614249f420ec62398957087b1'
>>> result.filesize
11357

Streaming API#

For large files or streaming data, use the processor classes:

from iscc_sum import IsccSumProcessor

processor = IsccSumProcessor()
with open("large_file.bin", "rb") as f:
    while chunk := f.read(1024 * 1024):  # Read in 1MB chunks
        processor.update(chunk)

result = processor.result(wide=False, add_units=True)
print(f"ISCC: {result.iscc}")
print(f"Units: {result.units}")  # Individual Data-Code and Instance-Code

Development#

Prerequisites#

  • Rust (latest stable) - Install from rustup.rs
  • Python 3.10+
  • UV (for Python dependency management) - Install from astral.sh/uv

Quick Setup#

# Clone the repository

git clone https://github.com/bio-codes/iscc-sum.git
cd iscc-sum

# Install Python dependencies
uv sync --all-extras

# Setup Rust development components
uv run poe setup

# Build Python extension and run all checks
uv run poe all

Development Commands#

All development tasks are managed through poethepoet:

# One-time setup (installs Rust components)
uv run poe setup

# Pre-commit checks (format, lint, test everything)
uv run poe all

# Individual commands
uv run poe format        # Format all code (Rust + Python)
uv run poe test          # Run all tests (Rust + Python)
uv run poe typecheck     # Run Python type checking
uv run poe rust-build    # Build Rust binary
uv run poe build-ext     # Build Python extension

# Check if Rust toolchain is properly installed
uv run poe check-rust

Manual Setup (if needed)#

# Install all dependencies including dev dependencies
uv sync --all-extras

# Install Rust components manually
rustup component add rustfmt clippy

# Build Rust extension for Python
uv run maturin develop

# Run tests manually
cargo test        # Rust tests
uv run pytest     # Python tests

Building#

# Build Rust binary (creates isum executable)
cargo build --release

# Build Python wheels
maturin build --release

Funding#

This work was supported through the Open Science Clusters’ Action for Research and Society (OSCARS) European project under grant agreement Nº101129751.

See: BIO-CODES project (Enhancing AI-Readiness of Bioimaging Data with Content-Based Identifiers).

License#

This project is licensed under the Apache License, Version 2.0 - see the LICENSE file for details.

Citation#

if you use ISCC-SUM in your research, please cite:

DOI

@software{pan2025isccsum,
    title        = {BIO-CODES/ISCC-SUM: High-Performance ISCC Generation for Bioimaging Data - OSCARS Project},
    author       = {Pan, Titusz},
    year         = 2025,
    month        = jul,
    publisher    = {Zenodo},
    doi          = {10.5281/zenodo.16541262},
    url          = {https://doi.org/10.5281/zenodo.16541262},
    note         = {Supported by OSCARS (Open Science Clusters' Action for Research and Society) under European Commission grant agreement Nº101129751},
    version      = {0.1.0}
}