Select files and compute their message digests

Here you can take any file and have the message digests (a.k.a the hash, cryptographic checksum) computed. This should work even for large files (many GB) and be fairly quick, as the processing happens locally in your browser.

What is a message digest?

Message digests are used for many applications to identify any amount of data (so from tiny files to huge datasets) by a relatively short code (typically around 16 to 64 Bytes long). A good message digest (such as those used for cryptography) is impossible to forge, i.e. it's practically impossible to find another file which results in the same digest (a "collission"). There are a number of message digest in use, such as MD5 (old and no longer considered to be good enough for cryptography), SHA1 and SHA2 (in different length, written as SHA256, SHA384 or SHA512), and of course many more. Currently MD5 and SHA2-224/256/384/512 are computed.

Privacy

The file you select is processed in the browser and not uploaded to a server, i.e. it never leaves your machine. However it's hard to prove this, so you should be cautious. Some evidence for this statement is to observe the network monitor in your browser developer menu, which should show no network activity after the page has loaded. Also, the computation happens much faster than it takes to upload a file to a server, which is very noticable for large files.

More information

You can find some additional information about this here: Computing message digests in the browser

Select File