openssl


iv in hex to use: 31323334353637383132333435363738
key in hex to use: 31323334353637383132333435363738
executing: openssl enc -aes-128-cbc -d -in file.encrypted -nosalt -nopad -K 31323334353637383132333435363738 -iv 31323334353637383132333435363738

It works !