implement DH key exchange for existing project （给原项目加上DH密钥交换的实现）

what needs to be done is adding DH key exchange algorithm for my existing project on a webrtc server straming video and audio. My original project code was recording audio from browser and mobile and comparing them to be a second-factor authentication. And what I want to improve is using webrtc and streaming audio from both to compare them, instead of recording. What I have done so far is making a webrtc signalling server and a url link that streams video and audio. How the connection works now is We create a room with a roomID and the peers make a request to the server with the roomID in the url. RoomID will be put in the same room and they start streaming video and audio. But it's too insecure and I need to generate a diffie hellman key pair on each peer (both desktop and mobile) and exchange the public keys. But I could not figure out how DH key exchange works. And where the keys are stored in mobile and how I can access them from the mobile phone so that I can encrypt the audio with the phones public key and then on the phone i can decrypt it using the key. （需要做的是为我在webrtc服务器上直播视频和音频的现有项目增加DH密钥交换算法的功能。 我原来的项目代码是录音web端和手机端的音频，并将它们进行比较延迟，作为两个端是否是在同一环境的双因素身份验证。我要改进的是使用webrtc直播音频来比较它们，把录音这一步替换掉。 我已经做好了的是部署webrtc信号服务器和可以直播视频和音频的url链接。现在连接的运作方式是，我用一个roomID创建一个房间，然后用户群用url里的roomID向服务器发出请求。RoomID会被放在同一个房间里开始直播视频和音频。但为了安全原因，我现在还需要在每个用户群（手机端和web端）上生成一个DH密钥对然后交换公钥。 但我不知道DH密钥交换要怎么做，以及我不知道手机中的密钥存储在哪里，如何从手机上访问它们，来用手机的公钥加密音频。）