Мастер-лицензия для iOS

openssl genpkey -algorithm RSA -outform DER -out privateKey.der -pkeyopt rsa_keygen_bits:2048
# for MacOS
base64 -i privateKey.der -o privateKey.txt
# for Linux 
base64 -w 0 privateKey.der > privateKey.txt

openssl rsa -pubout -in privateKey.pem -out publicKey.pub
base64 -w 0 publicKey.pub > publicKey.txt

OZSDK(licenseSources: [LicenseSource], masterLicenseSignature: String? = nil, completion: @escaping ((LicenseData?, LicenseError?) -> Void))

setLicense(licenseSource: LicenseSource, masterLicenseSignature: String? = nil)

private func getSignature() -> String? {
    let privateKeyBase64String = "содержимое файла privateKey.txt"
 
    guard let data = Data(base64Encoded: privateKeyBase64String, options: [.ignoreUnknownCharacters]) else {
      return nil
    }
     
    let sizeInBits = data.count * 8
    let keyDict: [CFString: Any] = [
      kSecAttrKeyType: kSecAttrKeyTypeRSA,
      kSecAttrKeyClass: kSecAttrKeyClassPrivate,
      kSecAttrKeySizeInBits: NSNumber(value: sizeInBits)
    ]
     
    var error: Unmanaged<CFError>?
    guard let secKey = SecKeyCreateWithData(data as CFData, keyDict as CFDictionary, &error) else {
      return nil
    }
     
    guard let bundleID = Bundle.main.bundleIdentifier else {
      return nil
    }
    guard let signature = SecKeyCreateSignature(secKey,
                          .rsaSignatureMessagePKCS1v15SHA512,  // Это критично!!!!
                          Data(bundleID.utf8) as CFData,
                          &error) else {
      return nil
    }
    return (signature as Data).base64EncodedString()
  }