52 lines
1.8 KiB
Swift
52 lines
1.8 KiB
Swift
//
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// Copyright (c) 2018 Open Whisper Systems. All rights reserved.
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//
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import Foundation
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import SignalCoreKit
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@objc
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public class SMKUDAccessKey: NSObject {
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@objc
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public static let kUDAccessKeyLength: Int = 16
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@objc
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public let keyData: Data
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@objc
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public init(profileKey: Data) throws {
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guard let aesGcmKey = OWSAES256Key(data: profileKey) else {
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throw SMKError.assertionError(description: "Profile key is not valid AES GCM key.")
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}
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// We derive the "ud access key" from the private key by encrypting zeroes.
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let emptyPlaintextLength = 16
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let emptyPlaintext = Data(count: Int(emptyPlaintextLength))
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let initializationVector = Data(count: Int(kAESGCM256_DefaultIVLength))
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guard let keyData = Cryptography.encryptAESGCM(plainTextData: emptyPlaintext,
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initializationVector: initializationVector,
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additionalAuthenticatedData: nil,
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key: aesGcmKey) else {
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throw SMKError.assertionError(description: "Could not derive UD access key from profile key.")
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}
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guard keyData.ciphertext.count == SMKUDAccessKey.kUDAccessKeyLength else {
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throw SMKError.assertionError(description: "\(SMKUDAccessKey.logTag) key has invalid length")
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}
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self.keyData = keyData.ciphertext
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}
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@objc
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public init(randomKeyData: ()) {
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self.keyData = Randomness.generateRandomBytes(Int32(SMKUDAccessKey.kUDAccessKeyLength))
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}
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// MARK:
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override public func isEqual(_ object: Any?) -> Bool {
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guard let other = object as? SMKUDAccessKey else { return false }
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return self.keyData == other.keyData
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}
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}
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