You can derive a deterministic key using the Dstack SDK inside Docker. Under the hood, the TappdClient derives the key from the application root key. 
import { TappdClient } from '@phala/dstack-sdk';

const keyResult = await client.deriveKey('<unique-id>'); // Same unique-id will get same key
console.log(keyResult.key); // X.509 private key in PEM format
console.log(keyResult.certificate_chain); // Certificate chain
const keyBytes = keyResult.asUint8Array(); // Get key as Uint8Array

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Derive wallet using viem

DStack SDK provides a helper function to derive a viem compatible wallet. 
import { toViemAccount } from '@phala/dstack-sdk/viem';

const keyResult = await client.deriveKey('<unique-id>'); // Same unique-id will get same key
const account = toViemAccount(keyResult);
// Use the account with viem operations

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Derive Solana Wallet

If you want to derive a Solana wallet, you can use the following code that derive a Solana wallet based on Solana Web3.js. 
import { toKeypair } from '@phala/dstack-sdk/solana';

const keyResult = await client.deriveKey('<unique-id>'); // Same unique-id will get same key
const keypair = toKeypair(keyResult);