# Crypto On-Ramp and Off-Ramp

Crypto on-ramp and off-ramp is an intractable issue to the crypto users, due to the fairness, security and compliance problems.

With NexaID zkTLS technique, one can create a secure end-to-end crypto on and off-ramps solution on the blockchain. Suppose Alice want to buy some crypto tokens with fiat from Bob. The general workflow of such an on/off-ramp protocol can be as the following.

* Deploy an on-chain escrow smart contract to securely hold tokens (e.g., USDC, ETH). These tokens are released only after verifying the corresponding off-chain payment. The escrow is pre-funded by Bob.
* Alice initiates a payment using platforms like Paypal or similar Web2 payment services.
* Using zkTLS, Alice creates a data proof, which validates key transaction details, including sender, recipient, and payment amount.
* The verified proof is submitted to the on-chain escrow smart contract, which processes it. Once the proof is confirmed, the escrow releases the tokens directly to Alice's wallet.


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