无法在aws beanstalk ec2上安装phpseclib

I'm trying to use phpseclib at AWS Beanstalk but it seems impossible to get it working.

My composer.json has "phpseclib/phpseclib": "2.0" line but after composer install it didn't shows phpseclib folder at vendor directory. It looks like that this line is being ignored.

So I'm trying to install it manually:

[ec2-user@ip-xxx-xxx-xx-xx html]$ sudo php composer.phar require phpseclib/phpseclib:~2.0
Do not run Composer as root/super user! See https://getcomposer.org/root for details
./composer.json has been updated
Loading composer repositories with package information
Updating dependencies (including require-dev)

So it's still the same: phpseclib is not present at vendors folder.

Any idea on that?