# sequential-hash

A lexicographical ordered rolling hash

```
npm install sequential-hash
```

[![build status](http://img.shields.io/travis/mafintosh/sequential-hash.svg?style=flat)](http://travis-ci.org/mafintosh/sequential-hash)

## Usage

``` js
var seqhash = require('sequential-hash')
var hash = seqhash('sha256') // sha256 is the hash algorithm

var prev = null
var words = ['mathias', 'wrote', 'this']

words.forEach(function (word) {
  prev = hash(word, prev)
  console.log(prev + ' -> ' + word)
})
```

Running the above produces

```
00!c1768bf97517f3da6948ee49b4d7078890c910a9fc07065a382184a4a3d9457a -> mathias
01!f16200e82c592e37e0f938c12ba4b3d88aa61b1df873ab03b60932956211ec03 -> wrote
02!34efbd1375266a04c302de321196d0a029bee922ca8044fe2cf8ca38289e3333 -> this
```

## API

#### `hash = seqhash(algo)`

Create a rolling hash function based on a hash algorithm (`sha1`, `sha256`, etc)

#### `hashString = hash(value, [previousHash])`

Hash a value based on a previous hash. The returned `hashString` is guaranteed to sort
lexicographically higher than `previousHash`.

## License

MIT


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sequential-hash

mafintosh

(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

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Bad semver

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Bad dependency semver

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Bidirectional unicode control characters

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Bin script confusion

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

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Chrome: Content Script

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

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Chrome: Host Permission

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

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Chrome: Permission

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

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Chrome: 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

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Title

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Possible typosquat attack

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Dynamic require

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Empty package

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Wildcard dependency

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A GitHub context variable (such as issue title, PR description, or comment body) is being exported as an environment variable. These context values are user-controlled and could be exploited by subsequent workflow steps.

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A GitHub context variable (such as issue title, PR description, or comment body) is being passed back as an output. These context values are user-controlled and could be exploited by consuming workflows.

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A GitHub context variable (such as issue title, PR description, or comment body) flows into a dangerous sink (such as shell command execution). This is a critical security issue that could allow command injection or code execution attacks.

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An environment variable flows into a dangerous sink (such as shell command execution). If this environment variable comes from an untrusted source, it could be exploited to inject commands.

GitHub Actions: Environment variable flows to dangerous sink

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AI-detected potential code anomaly

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AI-detected possible typosquat

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AI-detected potential malware

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Native code

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High entropy strings

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Unicode homoglyphs

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HTTP dependency

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Install scripts

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Invisible chars

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Non-existent author

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Missing dependency

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Missing license

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Missing package tarball

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Mixed license

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Modified license exception

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sequential-hash

sequential-hash

Usage

API

hash = seqhash(algo)

hashString = hash(value, [previousHash])

License

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`hash = seqhash(algo)`

`hashString = hash(value, [previousHash])`