how mediafilesegmenter generat AES-128 HLS?

I am using below commad line to generate AES-128 HLS,

mediafilesegmenter -iso-fragmented --encrypt-key-file=my.key -S -f /Volumes/Samsung/pattern/vision_pro/hls/*** /Volumes/Samsung/pattern/vision_pro/***.mov

but it always generates SAMPLE-AES, even I removed -S

#EXT-X-KEY:METHOD=SAMPLE-AES,URI="enc.key",IV=0x7316166d6a85f56f3d4606eaebc3aa44

How I can generate AES-128 HLS? Thanks.