Skip encrypting firt empy block.
Verified, that non padding occurs in AES-CTR mode.

$openssl aes-128-ctr -e -K c96b8a45affc5c9050378dd32168c381 -iv 41e31e41e3f8c26f0000000000000000 -in /etc/fstab | sha1sum
08fef883b3edcc6dc3e17e69e5da9e49bb7e3af9  -

$./openssl-aesctr </etc/fstab | sha1sum
key:    c96b8a45affc5c9050378dd32168c381
nonce_counter:  41e31e41e3f8c26f0000000000000000
fread: No such file or directory
AES CTR has no padding. Expecting out_len to be 0. Got 0.
08fef883b3edcc6dc3e17e69e5da9e49bb7e3af9  -