77 lines
2.2 KiB
Swift
77 lines
2.2 KiB
Swift
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//
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// MLCrypto.swift
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// monalxmpp
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//
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// Created by Anurodh Pokharel on 1/7/20.
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// Copyright © 2020 Monal.im. All rights reserved.
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//
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import UIKit
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import CryptoKit
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import ASN1Decoder
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@objcMembers
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public class MLCrypto: NSObject {
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public func encryptGCM (key: Data, decryptedContent:Data) -> EncryptedPayload?
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{
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let gcmKey = SymmetricKey.init(data: key)
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let iv = AES.GCM.Nonce()
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do {
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let encrypted = try AES.GCM.seal(decryptedContent, using: gcmKey, nonce: iv)
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let encryptedPayload = EncryptedPayload()
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let combined = encrypted.combined
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let ciphertext = encrypted.ciphertext
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if let combined = combined {
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let ivData = combined.subdata(in: 0..<12)
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//combined is in the format
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//iv+body+auth
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let range = 12+ciphertext.count..<combined.count //16 is gnereally tag size apple uses
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let tagData = combined.subdata(in:range)
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encryptedPayload.updateValues(body:ciphertext, iv: ivData, key:key, tag:tagData)
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encryptedPayload.combined = combined
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return encryptedPayload
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} else {
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return nil;
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}
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} catch {
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return nil
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}
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}
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// generate 12 byte nonce
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public func genIV() -> Data?
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{
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return Data(AES.GCM.Nonce())
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}
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public func decryptGCM (key: Data, encryptedContent:Data) -> Data?
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{
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do {
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let sealedBoxToOpen = try AES.GCM.SealedBox(combined: encryptedContent)
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let gcmKey = SymmetricKey.init(data: key)
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let decryptedData = try AES.GCM.open(sealedBoxToOpen, using: gcmKey)
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return decryptedData
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} catch {
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DDLogWarn("Could not decrypt GCM. Returning nil instead: \(String(describing:error))")
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return nil;
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}
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}
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public func getSignatureAlgo(ofCert certData:Data) -> String?
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{
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do {
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let x509 = try X509Certificate(data:certData)
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DDLogVerbose("ASN1 decoded cert: \(x509.description)")
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return x509.sigAlgOID
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} catch {
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DDLogError("ASN1 error: \(error)")
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return nil
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}
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}
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}
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