// In this example we use the same prime that BouncyCastle tests use.
let N = data(hex: "EEAF0AB9ADB38DD69C33F80AFA8FC5E86072618775FF3C0B9EA2314C"
    + "9C256576D674DF7496EA81D3383B4813D692C6E0E0D5D8E250B98BE4"
    + "8E495C1D6089DAD15DC7D7B46154D6B6CE8EF4AD69B15D4982559B29"
    + "7BCF1885C529F566660E57EC68EDBC3C05726CC02FD4CBF4976EAA9A"
    + "FD5138FE8376435B9FC61D2FC0EB06E3")

// In this example we use the same prime that BouncyCastle tests use.
let g = data(hex: "02")

// Use SHA256 as the hashing function, and HMAC-SHA256 as the HMAC function.
let srp256 = try SRP.iMath.protocol(N: N, g:g, digest: CryptoAlgorithm.SHA256.digestFunc(), hmac: CryptoAlgorithm.SHA256.hmacFunc())

// Normally you would get this from the user:
let userName = "alice".data(using: .utf8)!
// Normally you would get this from the user:
let userPassword = "password123".data(using: .utf8)!

// Just a way to generate the salt... (implemented in a separate category)
let salt = Data.generateRandomBytes(count: 128)

// Generate the verifier
let srpData: SRPData = try srp256.verifier(s: salt, I: userName, p: password)
let verifier: Data = srpData.verifier()

// Now you must send the salt, userName, and the verifier to the server.

let srp = try SRP.iMath.protocol(N: N, g:g, digest: CryptoAlgorithm.SHA256.digestFunc(), hmac: CryptoAlgorithm.SHA256.hmacFunc())

// TODO: Obtain the salt and parameter 'B' from the server.
// Also, the server can send a number of HMAC keys to generate shared session keys.
// let salt: Data = ...
// let B:Data = ...
// let hmacKey1: Data = ...

// TODO: Obtain the userName and password from the user.
// let userName: Data = ...
// let password: Data = ...

var srpData = try srp.generateClientCredentials(s:salt, I:userName, p:password)

srpData.serverPublicValue = B

srpData = try srp.clientEvidenceMessage(srpData: srpData)

// Now send the following values to the server:
// - userName
// - srpData.clientM.serialize()
// - srpData.A.serialize()

// The server will verify the client evidence and, if successful, should send back its own evidence message: serverM
srpData.serverEvidenceMessage = serverM

// Validate the server evidence message:
try srp.verifyServerEvidenceMessage(srpData: clientSRPData)

// Now derive the shared session key.
let clientSharedSessionKey: Data = try! srp.calculateClientSharedKey(srpData: clientSRPData, salt: hmacKey1)