Generate Hash of File using OpenSSL

Cryptographic hash functions can be used for verifying file integrity. For example, to check that the file has not been altered during transfer over the network. This tutorial explains how to generate a hash of a file using OpenSSL.

Let's say we have the following file named data.txt:

Hello world

The openssl dgst command can be used to perform various digest operations. To generate a hash of the file data.txt using SHA-256, run the following command:

openssl dgst -sha256 data.txt

Output:

SHA256(data.txt)= 64ec88ca00b268e5ba1a35678a1b5316d212f4f366b2477232534a8aeca37f3c

To write result to a file, use -out option:

openssl dgst -sha256 -out data.sha256 data.txt 

To get a list of supported cryptographic hash functions, use the following command:

openssl list --digest-commands

Output example:

blake2b512        blake2s256        gost              md4
md5               mdc2              rmd160            sha1
sha224            sha256            sha3-224          sha3-256
sha3-384          sha3-512          sha384            sha512
sha512-224        sha512-256        shake128          shake256
sm3