$ printf 'Hello world' | openssl enc -a -iv 62637377656261707031323334353637 -K 30413046344246453934384544393637 -aes-128-cfb 6YEgGREIkUnY88s= $ printf '6YEgGREIkUnY88s=' | openssl enc -d -a -iv 62637377656261707031323334353637 -K 30413046344246453934384544393637 -aes-128-cfb