Newsletter No. 474

In a warm and humid place like Hong Kong, mosquitoes are a fact of life. Many diseases such as dengue and Japanese Encephalitis come with this fact of life. Now the whole world has been put on alert to the latest addition to the armory of mosquitoes—the Zika virus, first discovered in Uganda in 1947 and now wreaking havoc in South America and threatening the rest of the world. Prof. Chan Kay-sheung Paul ( photo ), Chairman and Professor (Clinical) of the Department of Microbiology of CUHK, said that the Zika virus can multiply in a mosquito vector ( Aedes aegypti or Aedes albopictus ). After a period of about 10 days depending on the temperature, an infected mosquito can pass the virus on to human beings when taking blood from them. About one in five infected persons would experience mild symptoms including fever, rash, red eyes and joint pain. However, the recent outbreak in South America suggests, albeit unconfirmed yet, that some people may develop neurological problems or the virus may affect the brain development of their fetuses. In Brazil, an alarming number of cases of microcephaly (a birth defect of a shrunken head in the newlyborns) connected to Zika infection have been reported. According to Professor Chan, ‘The life cycle of the Zika virus is maintained by a high density of human beings and a high density of mosquitoes (the Aedes species). In a world connected by frequent flights, it’s highly likely that travelers may bring back the virus. If our mosquito control is not good enough, the infection can spread in Hong Kong as we already have a high population density.’ 人蚊持久戰 The Battle Goes On 在香港這般溫暖潮濕的地方，蚊子是一年四季的常客。許多 疾病，諸如登革熱、日本腦炎，都由蚊子而起。世界各地正嚴 陣以待防範蚊子兵團的最新武器—寨卡病毒，1947年首現 於非洲烏干達，近期肆虐南美，威脅全球。 中大醫學院微生物學系系主任 陳基湘 教授（ 圖 ）指出，寨卡 病毒可在蚊媒（埃及伊蚊或白紋伊蚊）身上繁殖。視乎溫度， 受感染的蚊約十天後，便可透過叮咬把病毒傳到人體。 每五位受感染者中約有一人出現發燒、皮疹、紅眼、關節痛 等輕微徵狀。儘管尚未百分百證實，但南美最近的疫情顯 示，病毒可能引致神經系統問題，或影響胎兒腦部發展。巴 西出現了為數驚人的小頭症（初生嬰兒頭部異常細小）病 例，相信和感染寨卡病毒有關。 陳教授說：「寨卡病毒的生命周期依賴高密度人群與高密度 蚊子（伊蚊類）來維持。國際航班頻繁，旅客很大機會帶病 毒回家。若控蚊措施不足，傳染病可能擴散至香港，畢竟我 們人口密度本來 就高。」 陳教授建議，到 爆發疫情的國 家旅遊前須三 思，如果決意前 往，應做足防蚊 措施，並持續到 抵港後至少兩 個星期。 寶健保健 Wealth In Health Professor Chan further advised that people travelling to countries with outbreaks should think twice, and if they decided to go should have proper protection against mosquitoes and continue that for at least two weeks after returning to Hong Kong. Photo by ISO staff 字裏高科 Tech Talks The debate was presented in the media as a tug-of-war between privacy and law enforcement. But one couldn’t help to ask: why does law enforcement lack the means to decode? How would they get it? Once they have it, how could this power be properly checked? Once the relevant technology comes into the public domain, what should be done to ensure that it is not appropriated for illegal purposes? No simple answers could be given to the above questions in this column. Readers, however, should be in possession of the following facts: currently the most important means of ensuring the security of digital messages is cryptography which is based on number theory; it arose during the two world wars when military communications had to be encrypted, and its subsequent spread to global commercial uses is hardly reversible now; unlike conventional weaponry, the mathematical knowledge of cryptography is neither proprietary nor expensive to develop. That is why cryptographic technology was listed in The Wassenaar Arrangement on Exports for Conventional Arms and Dual-Use Goods and Technologies about 20 years ago. If a manufacturer of communications technology offers a product found to have fallen below the safety standards or have backdoor access planted in it, its sales and competitiveness will be seriously affected, thereby making an already complicated situation even more complicated. 梁光漢 Philip Leung There has recently been a widespread debate on whether Apple Computer should accede to the request of FBI to crack a phone lock to help with its investigation. The issues can be seen from the political, human rights and counter-terrorism perspectives, with repercussions on the telecommunications policies of many countries and regions, and raising further questions of the ownership and user’s right of encryption technology. 密碼戰爭 The Code War 最近的一個熱門話題，是蘋果電腦應否應美國聯邦調查局 要求協助搜證，破解一部手機的鎖機密碼。議題之所以引起 廣泛討論，因為它涉及政治、人權、反恐等問題，而且影響到 各個國家地區的電信政策，引起對加密技術的擁有和使用權 的爭議。 事件在主流媒體普遍被看成是保障個人私隱和治安執法的 角力。但我們得問，執法機關為什麽缺乏破解密碼的能力？ 它們又如何可以獲得這個能力？當執法機關一旦擁有這個能 力後，社會如何能够適當地制衡這個權力？在一些相關技術 被公開後，如何確定它不會落入不法分子手裏？ 問題並非本欄以三言兩語可以說得清楚。但有幾點事實讀者 是應該知道的：當今保障數碼信息安全最重要的手段是密 碼術，它以數論為基礎；密碼術源起於兩次大戰時軍事通信 有需要加密，但隨著全球數碼商業的普及，它的民用需求已 經不能逆轉；與武裝軍備不同，密碼術的數學知識不是任何 一個人可以專享，創造和研發也無需投入龐大資源。 這些特點促使密碼技術在二十年前，被列入《瓦聖納協定》 內，與其他常規武器及軍民兩用貨品和技術一同受到出口管 制。因此，某些國家的信息技術生產商的產品，若一旦被視 為低於安全標準或可能被植入後門，將嚴重影響其銷量和 競爭力。加上這個潛在的商業考慮，一件開啟機鎖的事件便 變得無比複雜。 474 • 19.3.2016 7