End to end data encryption?

[SpaceBeeGaming 3]

Hello. So, I'm making an (in-game) monetary transaction system and for that I need encryption. Documentation on the data card is extremely poor (no examples). Here's what I have so far: 

Note! The key transfer has already been done.

--Machine #A
local pubKeyA, privKeyA = data.generateKeyPair()
local shKeyA = data.ecdh(privKeyA, pubKeyB)

local message = "Hello?"
---[What happens in here to encrypt data?]

modem.send(encryptedData) --just placeHolder

--Machine #B
local pubKeyB, privKeyB = data.generateKeyPair()
local shKeyB = data.ecdh(privKeyB, pubKeyA)

local message=event.pull() --just placeholder
---[What happens in here to decrypt data?]

print(decryptedData)

Any and all help would be appreciated.