It seems both
-pass can be used to encrypt files with a 2048 bit keyfile? I don't understand the difference between the two methods:
$ openssl enc -salt -aes-256-cbc -in inputfile.txt -kfile 2048bit_keyfile.key $ openssl enc -salt -aes-256-cbc -in inputfile.txt -pass file:2048bit_keyfile.key -out outputfile.txt.enc
Which method uses the full entropy of the 2048 bit keyhole?