OpenSSL can compute a checksum (digest) against a file.

To ensure that the contents of a file has not been tampered with, OpenSSL can compute a unique checksum for the file.

Once this checksum is computed, it can be shared and, for example, anyone downloading the file can run the same checksum process to ensure that they get the same checksum - which ensures that the contents of a file have not changed.

openssl dgst -list

returns:

Supported digests:
-blake2b512                -blake2s256                -md4                      
-md5                       -md5-sha1                  -ripemd                   
-ripemd160                 -rmd160                    -sha1                     
-sha224                    -sha256                    -sha3-224                 
-sha3-256                  -sha3-384                  -sha3-512                 
-sha384                    -sha512                    -sha512-224               
-sha512-256                -shake128                  -shake256                 
-sm3                       -ssl3-md5                  -ssl3-sha1                
-whirlpool

openssl dgst -md5 test.sh

returns:

MD5(test.sh)= 68e2009b8a69745f4371011194a16116

openssl md5 test.sh