Pjsip cipher 256

They choosing 256, 200 OK (SDP) confirm it:

xv=0
xo=- 2547899744 3 IN IP4 172.25.73.249
xs=Asterisk
xc=IN IP4 172.25.73.249
xt=0 0
xm=audio 10854 RTP/SAVP 18 101
xa=crypto:1 AES_256_CM_HMAC_SHA1_80 inline:2xwbrvIZOV7hBuH+JzrYLl/cMYug4MwoQbQS22VQrFczZ0zuOvgbUdiGGA5Rxg==
xa=rtpmap:18 G729/8000
xa=fmtp:18 annexb=no
xa=rtpmap:101 telephone-event/8000
xa=fmtp:101 0-16
xa=ptime:20
xa=maxptime:230
xa=sendrecv