CryptoSwift — Cryptographic Algorithms in Pure Swift

Introduction

CryptoSwift is a pure-Swift implementation of standard cryptographic primitives. It provides hash functions, ciphers, MACs, key derivation, and authenticated encryption without relying on CommonCrypto or any C libraries, making it portable across all Apple platforms and Linux.

What CryptoSwift Does

• Implements hash functions: MD5, SHA-1, SHA-2 (224/256/384/512), SHA-3
• Provides symmetric ciphers: AES (128/192/256), ChaCha20, Blowfish, Rabbit
• Supports block cipher modes: ECB, CBC, CTR, GCM, CCM, CFB, OFB
• Includes HMAC, CMAC, Poly1305 message authentication codes
• Offers PBKDF2, HKDF, and Scrypt key derivation functions

Architecture Overview

Each algorithm is implemented as a standalone Swift type conforming to shared protocols (Cipher, Authenticator, Digest). Data flows through a consistent bytes-in, bytes-out interface using Array. The library avoids Foundation dependencies where possible, operating on raw byte arrays for maximum portability. Extensions on String and Data provide convenience wrappers.

Self-Hosting & Configuration

• Add via SPM from krzyzanowskim/CryptoSwift
• Or via CocoaPods: pod 'CryptoSwift', '~> 1.8'
• No system-level C dependencies; compiles on all Swift platforms including Linux
• Supports iOS 13+, macOS 10.15+, tvOS 13+, watchOS 6+
• Thread-safe for concurrent encryption/decryption operations

Key Features

• Pure Swift with no bridging to C libraries
• Incremental processing support for large data via update/finalize pattern
• AES-GCM authenticated encryption for modern security requirements
• Padding options: PKCS7, zero padding, NoPadding, ISO10126, ISO78164
• Extensions on Data and String for one-liner hashing and encryption

Comparison with Similar Tools

• Apple CryptoKit — hardware-accelerated, Apple-only; CryptoSwift supports Linux and offers more algorithm variety
• CommonCrypto — C-based system library; CryptoSwift provides a friendlier Swift-native API
• OpenSSL (via SwiftNIO) — full TLS stack; far heavier for simple encrypt/hash operations
• Sodium (libsodium) — opinionated high-level crypto; CryptoSwift gives lower-level algorithm choice
• RNCryptor — simplified encrypt/decrypt wrapper; CryptoSwift offers more granular control

FAQ

Q: Is CryptoSwift suitable for production security applications? A: It implements standard algorithms correctly, but for high-security applications consider Apple CryptoKit which uses hardware acceleration and has undergone formal audit.

Q: Does CryptoSwift support AES-GCM authenticated encryption? A: Yes. Use AES with GCM block mode for combined encryption and authentication.

Q: Can I use CryptoSwift on Linux? A: Yes. It is pure Swift with no Apple framework dependencies, making it fully compatible with Swift on Linux.

Q: How does performance compare to CommonCrypto? A: CommonCrypto uses hardware AES-NI instructions and is faster for bulk operations. CryptoSwift is adequate for typical app-level encryption workloads.

Sources

• https://github.com/krzyzanowskim/CryptoSwift
• https://cryptoswift.io