Sina UC Censorship Research

"消息包含敏感字符！" (Message contains sensitive characters!)

Check out the...

corresponding paper and slides.

Censorship of the Day

These are recently retrieved, decrypted lists of the keywords that Sina UC downloads when starting up.

List1 (retrieved 7/17/2016)
List2 (retrieved 7/17/2016)
List3 (retrieved 7/17/2016)
List4 (retrieved 7/17/2016)
List5 (retrieved 7/17/2016)

Censorship Analysis

Sina UC 8.3.4.22616 has two sources for lists of keywords: built-in and downloaded. Both sources are encrypted with the 'H177UC09VI67KASI' 16-byte Blowfish key in ECB mode, then JSON-encoded, then encoded as an ASCII hex string. The built-in source is embedded in IMResource.dll. The downloaded source is retrieved from http://im.sina.com.cn/fetch_keyword.php?ver=8.3.4.22616. Each source contains five lists of keywords (downloaded list retrieved 8/25/11):

List1: List1 censors one-on-one text chat, group text chat, usernames (replacing username with a UID#), and mood indications.
- Built-in (160 words)
- Built-in with machine translations
- Downloaded (185 words)
- Downloaded with machine translations
List2: List2 censors usernames (replacing username with a UID#) and mood indications.
- Built-in (605 words)
- Built-in with machine translations
- Downloaded (626 words)
- Downloaded with machine translations
List3: List3 has no purpose in the version analyzed.
- Built-in (40 words)
- Built-in with machine translations
- Downloaded (50 words)
- Downloaded with machine translations
List4: List4 censors one-on-one text chat.
- Built-in (38 words)
- Built-in with machine translations
- Downloaded (380 words)
- Downloaded with machine translations
List5: List5 censors group text chat.
- Built-in (34 words)
- Built-in with machine translations
- Downloaded (365 words)
- Downloaded with machine translations

Decryption

The first python program decrypt.py takes an ASCII hex string from stdin and outputs the decrypted JSON plaintext to stdout. The second program dejson.py takes a JSON file foo and outputs a file fooi containing a line-delimited list of keywords for each keyword list i in foo.

This material is based upon work supported by the National Science Foundation under Grant No. 0844880. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.