Debian 的 64-bit time_t 計畫

在「Debian: 64-bit time_t transition in progress」這邊看到 Debian 的 mailing list 上的討論:「64-bit time_t transition in progress」,另外官方也有整理 wiki page:「64-bit time」。

因為技術上無法表示 2038/01/19 以後的時間,確定會 breaking ABI 將 time_t 從 32-bit 變成 64-bit,而現在要想辦法搞定 32-bit 平台上面可以處理這樣的改變:

The goal of this transition is to ensure that 32-bit architectures in trixie (whether they are currently release architectures, or out of archive, etc) will be capable of handling current and future timestamps referring to times beyond 2038.

離 2038/01/17 還有約 13 年多...

Safari 將會禁止長效憑證 (超過 398 天,大約十三個月)

在「Apple drops a bomb on long-life HTTPS certificates: Safari to snub new security certs valid for more than 13 months」這邊看到的,這次是 Safari 直接發難要幹掉長效憑證。

今年九月前發的憑證是照既有的協議,最長長度是 825 天 (大約 27 個月),但九月開始發的憑證,如果有效長度超過 398 天就會直接被 Safari 視為無效,所以大約是砍半,其他家瀏覽器不知道會不會跟進...

最早的時候可以直接買五年 (有印像是因為當年的 是我自己買的),後來好像降到三年,最近是兩年,看起來要變成一年了...

ROCA:Infineon Technologies 的 RSA 實做問題

最近的另外一個大包,不過這包是 Infineon Technologies 在實做 RSA 算法時的問題,倒不是 RSA 算法本身有問題。之所以會「大」是因為有太多人用了:「ROCA: Vulnerable RSA generation (CVE-2017-15361)」。

起因於 Infineon Technologies 在產生 key 時的組合有限,於是要猜測的 keyspace 小很多。

以研究者的估算,可以看出 CPU year 都被大幅減少了,都是屬於「可行」的範圍:

The time complexity and cost for the selected key lengths (Intel E5-2650 v3@3GHz Q2/2014):

512 bit RSA keys - 2 CPU hours (the cost of $0.06);
1024 bit RSA keys – 97 CPU days (the cost of $40-$80);
2048 bit RSA keys – 140.8 CPU years, (the cost of $20,000 - $40,000).

而且這邊是用 CPU year 估算,如果考慮 FPGA 加速計算,應該會短更多...


2nd of November 2017 - Presentation of all details at the ACM CCS conference (to come)
16th of October 2017 - The initial version of the public disclosure published
May to October 2017 - Cooperation with the manufacturer and other affected parties to help evaluate and mitigate the vulnerability
1st of February - The vulnerability disclosed to Infineon Technologies AG
End of January - The vulnerability found

過一陣子就會去 conference 上報告了...

Apple 的 App Store 的訂閱制度更新

先前在「蘋果 App Store 收費模式的改變」這邊提到的改變,這幾天細節公開了:「Subscriptions - App Store - Apple Developer」。

最主要的改變在於超過一年的費用從原來的 30% 降低到 15%:

Within a subscriber’s first year of an auto-renewable subscription, you receive the traditional 70% of the subscription price at each billing cycle, minus applicable taxes. After a subscriber accumulates one year of paid service, your revenue increases to 85% of the subscription price, minus applicable taxes.



分析信用卡四位數密碼的分佈:「PIN number analysis」。


Obviously, I don’t have access to a credit card PIN number database. Instead I’m going to use a proxy. I’m going to use data condensed from released/exposed/discovered password tables and security breaches.

19xx 那邊特別高,拉出來看可以看到分佈:(很像是出生年 XDDD)

相同的 abab (前兩碼與後兩碼相同) 也可以看出特別高,而 aaaa (四碼都一樣) 的特別亮:


另外是特別高的 1004 的原因:

Many people also asked the significance of 1004 in the four character PIN table. This comes from Korean speakers. When spoken, "1004" is cheonsa (cheon = 1000, sa=4).

"Cheonsa" also happens to be the Korean word for Angel.

Twitter 官方轉貼 CCTV 的「春晚」... XD

Twitter 官方的「Tweet #HappyChineseNewYear 2016 around the world」這篇在最後面轉貼了 CCTV 春晚的消息:

好像不只一點可以吐嘈的啊... 剛剛試著在帳號上找這則但沒找到,應該是被刪掉了?

Facebook 提供 Android 效能分級的函式庫

一樣是在 OSNews 上看到的,Facebook 提供了一套 Library,可以將 Android 裝置依照年份分類:「Facebook's simple trick for serving many different Android devices」,原始報導是「Facebook's simple trick for serving so many different Android devices」。

可以在 GitHub 上的「Device Year Class」看到如何使用的範例程式碼:

int year = YearClass.get(getApplicationContext());
if (year >= 2013) {
    // Do advanced animation
} else if (year > 2010) {
    // Do simple animation
} else {
    // Phone too slow, don't do any animations

寫起來感覺沒什麼節操,但很實用 XDDD

前幾天 Twitter 伺服器時間大爆炸的原因...

前幾天 Twitter 伺服器的時間大爆炸,跳到 2015 年:

剛剛在 Hacker News Daily 上看到原因:「If you're using YYYY in your JVM service or %G in anything, fix it now」,原因是這樣:

The single character G instead of Y took down Twitter's API today.
If you're using YYYY in your JVM service or %G in anything, fix it now. You're very likely using the wrong year format.

Mon Dec 29 00:44:45 EST 2014
date -u "+%G"

ISO 8601 week numbering has 2015 start this week.


gslin@home [~] [01:22/W4] date 
Wed Dec 31 01:27:00 CST 2014
gslin@home [~] [01:27/W4] date +%Y
gslin@home [~] [01:27/W4] date +%G

依照說明,%G 的用途是:

year of ISO week number (see %V); normally useful only with %V