Required functionalities

• Frontend
  • Wallet connect
  • Sign a message
• Backend
  • Signature verification (address + signature)
  • Send funds (coins / tokens)
  • Transaction fee estimation (coins / tokens)
  • Token swaps / test swaps
  • Input registration

Details

Signatures
DFX is required by law to verify that the address of a user really belongs to the user. This is done with a digital signature. The user signs a message with his private key and uses his address and the resulting signature to log in at DFX.

Swaps
It might be interesting to do swaps on a decentralized exchange (like Uniswap on Ethereum), if something like this exists on Solana. In addition we would need to do test swap for price estimations.

Input Registration
Our users should be able to send funds from every address (or even central exchanges) to DFX's off-ramp. We therefore assign every user a unique deposit address. As soon as some funds arrive there, we sell them and pay the fiat out to the user's bank account.
We need an efficient system to generate many addresses and register incoming transactions.