# VCDiff
This is a wrapper around Google's open-vcdiff library, which provides
an encoder and decoder for the format described in RFC 3284:
"The VCDIFF Generic Differencing and Compression Data Format."
The encoding strategy is largely based on Bentley-McIlroy 99:
"Data Compression Using Long Common Strings.

For more details visit: http://code.google.com/p/open-vcdiff

## Installing
	# Install the gem:
	sudo gem install romanbsd-vcdiff

## Usage
	require 'VCDiff'
	
	# Encoding
	dictionary = IO.read('dictionary_file')
	modified = IO.read('modified_file')
	# Optional
	encoder.format_flags = VCDiff::VCD_FORMAT_INTERLEAVED | VCDiff::VCD_FORMAT_CHECKSUM
	encoder = VCDiff::Encoder.new(dictionary)
	res = encoder.encode(modified)
	
	# Decoding
	decoder = VCDiff::Decoder.new
	orig = decoder.decode(dictionary, res)
	
	orig == modified	# -> true


vcdiff

Roman Shterenzon

(Experimental) An ambiguous license classifier was found.

What is an ambiguous license classifier?

Ambiguous License Classifier

Source files are encoded using a non-standard text encoding.

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Bad text encoding

Package version is not a valid semantic version (semver).

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Bad semver

Package has dependencies with an invalid semantic version. This could be a sign of beta, low quality, or unmaintained dependencies.

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Bad dependency semver

Source files contain bidirectional unicode control characters. This could indicate a Trojan source supply chain attack. See: trojansource.codes for more information.

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Bidirectional unicode control characters

This package has multiple bin scripts with the same name. This can cause non-deterministic behavior when installing or could be a sign of a supply chain attack.

What is bin script confusion?

Bin script confusion

This Chrome extension includes content scripts that execute JavaScript on specified websites.

What are Chrome extension content scripts?

Chrome Extension Content Script

This Chrome extension requests host permissions to access specific websites or domains.

What are Chrome extension host permissions?

Chrome Extension Host Permission

This Chrome extension requests permissions to access browser APIs, user data, or system features.

What are Chrome extension permissions?

Chrome Extension Permission

This Chrome extension requests wildcard host permissions that grant broad access to websites.

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Chrome Extension Wildcard Host Permission

Semantic versions published out of chronological order.

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Chronological version anomaly

Project maintainer's SSH key has been compromised.

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Compromised SSH key

(Experimental) Copyleft license information was found.

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Copyleft License

Contains a Critical Common Vulnerability and Exposure (CVE).

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Title

Critical CVE

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High CVE

Uses debug, reflection and dynamic code execution features.

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Debug access

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Deprecated

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Deprecated SPDX exception

(Experimental) License is deprecated which may have legal implications regarding the package's use.

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Deprecated license

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Possible typosquat attack

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Dynamic require

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Empty package

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Environment variable access

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File dependency

Accesses the file system, and could potentially read sensitive data.

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Filesystem access

Package has a dependency with a floating version range. This can cause issues if the dependency publishes a new major version.

What are wildcard dependencies?

Wildcard dependency

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Generic alert

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Git dependency

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GitHub dependency

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AI-detected possible typosquat

AI has identified this package as malware. This is a strong signal that the package may be malicious.

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AI-detected potential malware

AI has determined that this package may contain potential security issues or vulnerabilities.

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AI-detected potential security risk

Contains native code (e.g., compiled binaries or shared libraries). Including native code can obscure malicious behavior.

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Native code

Contains high entropy strings. This could be a sign of encrypted data, leaked secrets or obfuscated code.

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High entropy strings

Contains unicode homoglyphs which can be used in supply chain confusion attacks.

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Unicode homoglyphs

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HTTP dependency

Install scripts are run when the package is installed. The majority of malware in npm is hidden in install scripts.

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Install scripts

Package has an invalid manifest file and can cause installation problems if you try to use it.

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Invalid manifest file

Source files contain invisible characters. This could indicate source obfuscation or a supply chain attack.

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Invisible chars

(Experimental) Package license has recently changed.

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License change

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License exception

This package is not allowed per your license policy. Review the package's license to ensure compliance.

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License Policy Violation

Contains long string literals, which may be a sign of obfuscated or packed code.

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Long strings

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Major refactor

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Known malware

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Manifest confusion

Contains a medium severity Common Vulnerability and Exposure (CVE).

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Medium CVE

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Low CVE

This package contains minified code. This may be harmless in some cases where minified code is included in packaged libraries, however packages on npm should not minify code.

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Minified code

(Experimental) A package's licensing information has fine-grained problems.

Misc. License Issues

The package was published by an npm account that no longer exists.

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Non-existent author

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Missing dependency

(Experimental) Package does not have a license and consumption legal status is unknown.

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Missing license

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Missing package tarball

(Experimental) Package contains multiple licenses.

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Mixed license

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Modified license exception

(Experimental) Package contains a modified version of an SPDX license. Please read carefully before using this code.

What is a modified license?

Modified license

What is network access?

Network access

A new npm collaborator published a version of the package for the first time. New collaborators are usually benign additions to a project, but do indicate a change to the security surface area of a package.

What is new author?

New author

Package does not specify a list of contributors or an author in package.json.

Why is contributor and author data important?

No contributors or author data

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No bug tracker

(Experimental) License information could not be found.

No License Found

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No README

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vcdiff

VCDiff

Installing

Usage

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