Checksums

macOS workflow and shell script to calculate or automatically verify file checksums

Do you still need to launch third-party software to create or verify checksums? Do you need to copy and paste a checksum to verify it? Do you still use the command line to calculate checksums? Do you verify checksums visually? Do you need to publish file size information, too? Do you need to compare the contents of two folders? Do you have several applications for different tasks? Is there a checksum created with an unusual algorithm you can't verify?

No need for additional tools anymore. Do all the operations you would need (in most cases!) directly from the Finder, thanks to the power of Apple's macOS Services.

Minimum OS: OS X 10.8

Supported algorithms

macOS native

• CRC (BSD), CRC (System V), CRC (legacy 32bit) [decimal]
• CRC (ISO/IEC 8802-3:1989) [decimal]
• CRC-32 (sometimes called CRC-32b to distinguish from ethernet CRC-32)
• MD5-length: MD4, MD5, MDC-2
• SHA1-length: SHA-1, SHA-0, RIPEMD-160
• SHA2-class: SHA-224, SHA-256, SHA-384, SHA-512

Native calculations [scripted]

• Adler-32 (using adler32 from zlib)

Other [optional]

gsutil

• CRC-32C [hexadecimal]

rhash

• MD5-length: AICH, SNEFRU-128
• DC++ TTH
• SHA1-length: BTIH, HAS-160
• Tiger
• SHA3-class: SHA3-224, SHA3-256, SHA3-384, SHA3-512
• EDON-R 256, GOST, GOST CryptoPro, SNEFRU-256
• EDON-R 512, Whirlpool

transmission

• Bencode (BitTorrent hash)

Functionality

• default single file algorithm: SHA-256
• calculates default or user-selected checksum
• calculates file size (output: B, MB, MiB)
• copies all information incl. filename to clipboard
• parses clipboard content for possible checksums and auto-compares to calculated checksum
• ignores clipboard checksum if the same value was already checked in the previous run
• lots of additional checksum options, e.g. GOST, if the user has installed the rhash CLI
• BitTorrent file hash calculation is possible, if the user has installed the transmission CLI
• CRC-32C hash calculation is possible, if the user has installed the gsutil python CLI
• creates .sfv, .md5, .sha1, .sha256, or .sha512 checksum digests for all files in a selected directory (recursive, without invisibles)
• verifies .sfv, .md5, .sha1, .sha256, or .sha512 checksum digests for single or multiple files incl. directories (recursive, all files as per digest)
• compares two files using MD5
• compares contents of two directories using CRC-32 (recursive, with invisibles, without .DS_Store)

Notes

• MD2 calculation produces an error with openssl for macOS, so it is not enabled
• AICH and DC++ TTH (part of rhash) are not (yet?) available for automatic checksum comparison
• Bencode will work on .torrent files only
• For the Adler-32 calculation, a python script called adler32.py will be created in $HOME/Library/Caches/local.lcars.Checksums/bin

Future

• mhash integration via py-mhash (unsure)
• more CRC hashes via crccheck (unsure)

Installation

• Download the latest DMG and open

Workflow

• Double-click on the workflow file to install
• If you encounter problems, open it with Automator and save/install from there
• Standard Finder integration in the Services menu

Main shell script [optional]

Only necessary if for some reason you want to run this from the shell or another shell script. For normal use the workflow will be sufficient.

• Move the script checksums.sh to /usr/local/bin
• In your shell enter chmod +x /usr/local/bin/checksums.sh
• Run the script with checksums.sh /path/to/target

Uninstall

Remove the following files or folders:

$HOME/Library/Caches/local.lcars.Checksums
$HOME/Library/Preferences/local.lcars.Checksums.plist
$HOME/Library/Services/Checksums.workflow
/usr/local/bin/checksums.sh

Optional installations

gsutil

More information: gsutil

• first install current python (v2) with brew install python (or with a similar manager) which will include pip
• then install gsutil with pip install gsutil

rhash [recommended]

More information: rhash

• install using Homebrew with brew install rhash (or with a similar manager)

terminal-notifier [recommended]

More information: terminal-notifier

You need to have Spotlight enabled for mdfind to locate the terminal-notifier.app on your volume; if you don't install terminal-notifier, or if you have deactivated Spotlight, the Checksums scripts will call notifications via AppleScript instead

• install using Homebrew with brew install terminal-notifier (or with a similar manager)
• move or copy terminal-notifier.app from the Homebrew Cellar to a suitable location, e.g. to /Applications, /Applications/Utilities, or $HOME/Applications

transmission

More information: transmission

• install using Homebrew with brew install transmission (or with a similar manager)
• Checksums will use only the transmission-show binary

Screengrabs