FFMPEG Encryption

Question

I am doing a project with video encryption, and I have a few questions for the procedure.

I used the command to transcode mp4 to HLS with a ts segment duration of ~ 10 seconds.

First, I need to encrypt these videos using a key from the database. However, I do not know if encryption works with ffmpeg or not.

Secondly, if encryption can work without ffmpeg, then what should I do? I searched on google that includes something like openssl / aes, but for me there is no detailed step, not even a ffmpeg link: http://www.ffmpeg.org/ffmpeg-all.html#srtp

Can someone give me a hand to teach me how to encrypt a video? Thanks to you.

Answer 1

Yes, you can do it with ffmpeg . You need to write the key from the database to a file, say video.key .

You need a second file, name it key_info , which is the key information file. It has the following format:

 key URI key file path IV (optional) 

For instance:

 http://example.com/video.key video.key 

You tell ffmpeg use it to encrypt your segments with the hls_key_info argument:

 ffmpeg -i input.mp4 -c copy -bsf:v h264_mp4toannexb -hls_time 10 -hls_key_info_file key_info playlist.m3u8 

This will encrypt your segments with AES-128 in CBC mode and add the appropriate tags to your playlist:

 #EXT-X-KEY:METHOD=AES-128,URI="http://example.com/video.key" 

You can also manually encrypt segments if you want using openssl . Here is an example script where each IV is equal to the segment index:

 #!/bin/bash ts_dir=/path/to/ts/ key_file=video.key openssl rand 16 > $key_file enc_key=$(hexdump -v -e '16/1 "%02x"' $key_file) pushd $ts_dir ts_cnt=$(ls *.ts | wc -l) ((ts_cnt--)) i=0 for i in $(seq -f "%01g" 0 $ts_cnt); do iv=$(printf '%032x' $i) ts_file=segment-$i.ts echo [$i] $ts_file openssl aes-128-cbc -e -in $ts_file -out encrypted_${ts_file} -nosalt -iv $iv -K $enc_key done popd