41 lines
1.1 KiB
Swift
41 lines
1.1 KiB
Swift
//
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// Message+Extensions.swift
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// Sesame
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//
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// Created by CH on 08.04.22.
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//
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import Foundation
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import CryptoKit
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extension Message {
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static var length: Int {
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SHA256Digest.byteCount + Content.length
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}
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init<T: Sequence>(decodeFrom data: T) where T.Element == UInt8 {
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let count = SHA256Digest.byteCount
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self.mac = Data(data.prefix(count))
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self.content = .init(decodeFrom: Array(data.dropFirst(count)))
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}
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func isValid(using key: SymmetricKey) -> Bool {
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HMAC<SHA256>.isValidAuthenticationCode(mac, authenticating: content.encoded, using: key)
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}
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}
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extension Message.Content {
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func authenticate(using key: SymmetricKey) -> Message {
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let mac = HMAC<SHA256>.authenticationCode(for: encoded, using: key)
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return .init(mac: Data(mac.map { $0 }), content: self)
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}
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func authenticateAndSerialize(using key: SymmetricKey) -> Data {
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let encoded = self.encoded
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let mac = HMAC<SHA256>.authenticationCode(for: encoded, using: key)
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return Data(mac.map { $0 }) + encoded
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}
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}
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