Possible combinations are:
SSH-2.0-phpseclib_0.3
SSH-2.0-phpseclib_0.3 (gmp)
SSH-2.0-phpseclib_0.3 (bcmath)
SSH-2.0-phpseclib_0.3 (mcrypt)
SSH-2.0-phpseclib_0.3 (mcrypt, gmp)
SSH-2.0-phpseclib_0.3 (mcrypt, bcmath)