CryptoSwift/Sources/CryptoSwift/Cryptors.swift

//
//  CryptoSwift
//
//  Copyright (C) 2014-2017 Marcin Krzyżanowski <marcin@krzyzanowskim.com>
//  This software is provided 'as-is', without any express or implied warranty.
//
//  In no event will the authors be held liable for any damages arising from the use of this software.
//
//  Permission is granted to anyone to use this software for any purpose,including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:
//
//  - The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation is required.
//  - Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.
//  - This notice may not be removed or altered from any source or binary distribution.
//

#if os(Linux) || os(Android) || os(FreeBSD)
    import Glibc
#else
    import Darwin
#endif

/// Worker cryptor/decryptor of `Updatable` types
public protocol Cryptors: class {
    associatedtype EncryptorType: Updatable
    associatedtype DecryptorType: Updatable

    /// Cryptor suitable for encryption
    func makeEncryptor() throws -> EncryptorType

    /// Cryptor suitable for decryption
    func makeDecryptor() throws -> DecryptorType

    /// Generate array of random bytes. Helper function.
    static func randomIV(_ blockSize: Int) -> Array<UInt8>
}

extension Cryptors {
    public static func randomIV(_ blockSize: Int) -> Array<UInt8> {
        var randomIV: Array<UInt8> = Array<UInt8>()
        randomIV.reserveCapacity(blockSize)
        for randomByte in RandomBytesSequence(size: blockSize) {
            randomIV.append(randomByte)
        }
        return randomIV
    }
}