79 lines
2 KiB
Swift
79 lines
2 KiB
Swift
//
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// Copyright 2024 Signal Messenger, LLC
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// SPDX-License-Identifier: AGPL-3.0-only
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//
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import Foundation
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/// Key appropriate for use with AES-256.
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@objc(OWSAES256Key)
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public final class Aes256Key: NSObject, NSSecureCoding {
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@objc
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public static let keyByteLength: UInt = 32
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@objc
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public let keyData: Data
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/// Generates a new secure random key.
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public override init() {
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self.keyData = Randomness.generateRandomBytes(Self.keyByteLength)
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}
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/// Generates a new secure random key.
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///
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/// Equivalent to calling ``Aes256Key/init()``.
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@objc(generateRandomKey)
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public static func generateRandom() -> Aes256Key {
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return Aes256Key()
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}
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/// Returns a new instance if `data` is of appropriate length for an AES-256 key.
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///
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/// - Parameters:
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/// - data: the raw key bytes
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///
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/// - Returns: `nil` if the input `data` is not the correct length for an AES-256 key
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public init?(data: Data) {
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if data.count == Self.keyByteLength {
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self.keyData = data
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} else {
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Logger.error("Invalid key length: \(data.count)")
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return nil
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}
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}
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// MARK: Secure Coding
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public static let supportsSecureCoding: Bool = true
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public init?(coder: NSCoder) {
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let keyData = coder.decodeObject(of: NSData.self, forKey: "keyData")
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guard let keyData, keyData.count == Self.keyByteLength else {
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Logger.error("Invalid key length: \(keyData?.count ?? 0)")
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return nil
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}
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self.keyData = keyData as Data
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}
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public func encode(with coder: NSCoder) {
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coder.encode(self.keyData as NSData, forKey: "keyData")
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}
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// MARK: Equatable
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public override func isEqual(_ object: Any?) -> Bool {
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guard let otherKey = object as? Aes256Key else {
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return false
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}
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return otherKey.keyData.ows_constantTimeIsEqual(to: self.keyData)
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}
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// MARK: Hashable
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public override var hash: Int {
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return (self.keyData as NSData).hash
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}
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}
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