SwiftKeyExchange

let curve = KeyExchangeCurve.curve25519
let hashFunction = SHA256.self
let kdf = KeyExchangeKDF.hkdf
let aead = KeyExchangeAEAD.aesgcm

let plaintext = "exampleplaintext".data(using: .utf8)!
let additionalData = Data("abc".utf8)

// alice store
let aliceStore = try KeyExchangeStore(
    curve: curve,
    using: hashFunction,
    kdf: kdf,
    aead: aead,
    externalPublicKey: "" // a new public key is created if this string is left empty
)

// bob store
let bobStore = try KeyExchangeStore(
    curve: curve,
    using: hashFunction,
    kdf: kdf,
    aead: aead,
    externalPublicKey: "", // a new public key is created if this string is left empty
)

// Add private keys to the stores.
try! aliceStore.setExternalPublicKey(bobStore.LocalPublicKey())
try! bobStore.setExternalPublicKey(aliceStore.LocalPublicKey())

// Alice encrypt.
var v = try! aliceStore.encrypt(
    plaintext: plaintext,
    additionalData: additionalData
)

// Bob decrypt.
let bobPlaintext = try bobStore.decrypt(
    kdfNonce: v.kdfNonce,
    ciphertext: v.ciphertext,
    aeadNonce: v.aeadNonce,
    additionalData: v.additionalData
)

// Bob encrypt.
v = try! bobStore.encrypt(
    plaintext: plaintext,
    additionalData: additionalData
)

// Alice decrypt.
let alicePlaintext = try aliceStore.decrypt(
    kdfNonce: v.kdfNonce,
    ciphertext: v.ciphertext,
    aeadNonce: v.aeadNonce,
    additionalData: v.additionalData
)

print(plaintext == alicePlaintext)
print(plaintext == bobPlaintext)