Performing Common Cryptographic Operations

At a glance

Project structure

Source bundle/
└── Performing-Common-Cryptographic-Operations.playground/
    └── Pages/
        ├── Authenticating Data with HMAC.xcplaygroundpage/
        │   └── Contents.swift
        ├── Creating and Verifying Signatures.xcplaygroundpage/
        │   └── Contents.swift
        ├── Encrypting Data.xcplaygroundpage/
        │   └── Contents.swift
        ├── Encrypting and Signing with Public-Key Cryptography.xcplaygroundpage/
        │   └── Contents.swift
        ├── Hashing Data.xcplaygroundpage/
        │   └── Contents.swift
        ├── LICENSE.xcplaygroundpage/
        │   └── Contents.swift
        ├── Performing Key Agreement.xcplaygroundpage/
        │   └── Contents.swift
        └── Table of Contents.xcplaygroundpage/
            └── Contents.swift

Structure observations

• Architecturally prominent files are ranked from entry points and role-named declarations; resource-only paths are omitted.
• Primary languages: Swift.
• The verified tree contains 0 project/configuration file(s) and 0 source declaration(s).

Overall architecture

flowchart LR
    N1["Contents"]
    N2["CryptoKit APIs"]
    N1 --> N2

Reference code

Performing-Common-Cryptographic-Operations.playground/Pages/Authenticating Data with HMAC.xcplaygroundpage/Contents.swift:1 — architecture anchor

/*
See the LICENSE.txt file for this sample’s licensing information.

Abstract:
Shows how to authenticate data with HMAC.
*/

Interpretation

The arrows summarize the source-visible entry, role-named types or folders, and framework direction; when nodes come from structural folders, the sequence is a high-level interpretation rather than proof that every adjacent node calls the next. Ownership is claimed only where the next section cites a stored property or assignment. The diagram is intentionally limited to the dominant path into Apple CryptoKit.

Ownership and state

classDiagram
    Contents o-- Bundle : filePath
    Contents o-- FileManager : audioData
    Contents *-- SymmetricKey : key
    Contents o-- Authenticationcode : authenticationCode

Ownership evidence

Performing-Common-Cryptographic-Operations.playground/Pages/Authenticating Data with HMAC.xcplaygroundpage/Contents.swift:21 — stored dependency or nearest verified ownership anchor

let filePath = Bundle.main.path(forResource: "ThemeSong", ofType: "aif")!
let audioData = FileManager.default.contents(atPath: filePath)!
/*:
 Create a random symmetric key. The sender and the receiver must share this key.
 */
let key = SymmetricKey(size: .bits256)

Composition arrows indicate a source-visible construction expression or locally owned value state; aggregation means the owner stores or receives a dependency without proving exclusive lifetime ownership.

Class and protocol design

Performing-Common-Cryptographic-Operations.playground/Pages/Creating and Verifying Signatures.xcplaygroundpage/Contents.swift:16 — representative type boundary

import CryptoKit
let signingKey = Curve25519.Signing.PrivateKey()
/*:
 Get a data representation of the public key, which you publish freely.
 */
let signingPublicKey = signingKey.publicKey
let signingPublicKeyData = signingPublicKey.rawRepresentation

No local protocol conformance is claimed as protocol-oriented design; external framework conformances are listed only as dependencies.

Access control

Reference code

Performing-Common-Cryptographic-Operations.playground/Pages/Encrypting Data.xcplaygroundpage/Contents.swift:18 — representative boundary

import CryptoKit
import Foundation

let key = SymmetricKey(size: .bits256)

let themeSongPath = Bundle.main.path(forResource: "ThemeSong", ofType: "aif")!

Swift declarations without a modifier are internal; explicit private, fileprivate, private(set), public, or open entries above are interpreted by language semantics. Objective-C/C samples instead rely on header and implementation boundaries, which are not equivalent to Swift lexical privacy.

Logic ownership and placement

Design patterns

Naming conventions

• Types: feature-specific names rather than reusable layer suffixes.
• Protocols: no local protocol declaration in the scanned source.
• Methods: no representative method name extracted from the architectural files.
• Files: feature/project roles rather than a strict one-type-per-file rule.

Architecture takeaways

• Contents is the main source-visible entry or composition anchor for this sample.
• Framework work reaches CryptoKit through a deliberately small high-level chain; the detailed API graph remains inside the cited implementation files.
• Stored-property evidence identifies lifecycle collaboration; it does not by itself prove exclusive object ownership.
• Access-control conclusions separate verified language visibility from the likely design rationale.
• The source does not justify labeling the design protocol-oriented.

Source map

• Official Apple documentation