当前在线人数19030
DVE Encryption 2 - 未名空间精华区
首页 - 版面精华区 - 新闻中心精华区 - 科技新闻版精华区 - 精华区文章阅读 首页
未名交友
[更多]
[更多]
DVE Encryption 2

发信人: qaz (请不要在我的肩上哭泣), 信区: ITnews
标  题: DVD encryption mechanism
发信站: The unknown SPACE (Tue Nov 23 12:28:19 1999) WWW-POST

hehe, let me explain.

first dvd content can be encrypte. in fact, most of comerical dvd is
encrypted.

dvd player need to know the key to decode dvd content. we call this key is
content key.

every dvd manufactory need to apply a manufactory key from dvd comittee.
pay license fee and charge you lot of moeny. any way the manufactory key is
build in
player.

the content key will be encrypted by manufactory key and store in dvd disk.
there are multiple copies of this content key encrypted by different
manufactroy key
on the dvd disk.

if a player have a manufactory key. it will first try to decode content key.
once it find a mtach one. it use this key to decode dvd.

say, I can produce a dvd with only one contentkey copy encode in pioneer
manufactory key. then no other player can play it.

hacker break the xing dvd player get xing's manufactory key. somehow.
they went a step further that
they analysis the how the content key is encoded , they can now decode
the content key without any manufactroy key.

--
※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 206.75.92.37]
发信人: qaz (请不要在我的肩上哭泣), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Tue Nov 23 12:48:52 1999) WWW-POST

【 在 fencer (秋天的树) 的大作中提到: 】
: 【 在 qaz (请不要在我的肩上哭泣) 的大作中提到: 】
: : hacker break the xing dvd player get xing's manufactory key. somehow.
: : they went a step further that
: : they analysis the how the content key is encoded , they can now decode
: : the content key without any manufactroy key.
:                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
:                   哇塞?! 这么厉害..
:      你的说明我是对比Public KeyPair 来理解的
:      好象差不多. 不过, 没有manfacotry key 也能decode
:      content key,这个好象太难了. 至少说明原来的
:      加密方式有些土.        
:
yes. they first only have xing key. then they use xing key to decode a
content
key then reverse decode other manufactory key. finally, they got almost all
the
manufactory key. and find the universal method.

the dvd encryptiion is not very strong. because they are supposed to
inplement in hardware. because software dvd player. it is possible to
be break.

--
※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 206.75.92.37]
发信人: gesundheit (gesund), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Tue Nov 23 14:11:29 1999), 站内信件

【 在 qaz (请不要在我的肩上哭泣) 的大作中提到: 】

: That is what I am saying. the content key can be break without
: manufactory key.  so even a disc with a unknow manufactory key can
: be played.

I don't know what are you saying.  You mean the plain text
title key can be recovered with out a player key.  Or in another
words, the encryption algorithm is reversible.  I don't know
if it's reversible because I don't know the math of LFSR.
But if this is true, the stupidity of the people who designed
the CSS is hard to believe.

I think it's necessary to go through the CSS scrambling algorithm here.

the title key T for encrypted titles are encrypted by the disc key
T'=En(T, D)  where T' is the encrypted tiltle key, D is the plain text
disc key.  D is encrypted by a player key assigend to CSS licensee.
D'=En(D, P).  D' is avalaible in a 2048byte table vai dvd ROM interface
to the decoder.  The is also an assigned key index. Say, disc_key[2048]
is the disc key table.  The decode doesnt the following to recover
the plain text disc key:

D'=disc_key[p_index]  p_index is assigned player index
D=De(D', P)

Title key is then recovered by
T=De(T', D)

The descambling then takes off.
--
Keine Regel, ohne Ausnahme.

※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 128.148.44.167]
发信人: gesundheit (gesund), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Tue Nov 23 14:16:30 1999), 站内信件

【 在 blueatlas (77) 的大作中提到: 】
: dvd ROM 和 standalone players
: 分别是什么?
: 我的意思是难道不能生产个机器直接读光信号,直接送给dvd印刷机

DVD ROM is on computers.
Standalone players are the consumer DVD players.

It is possible in theory because all the specs of the physical
disc are know you can make your own reader and pass the raw
signal to the device to make a negetive mold disc.

--
Keine Regel, ohne Ausnahme.

※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 128.148.44.167]
发信人: gesundheit (gesund), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Wed Nov 24 14:21:30 1999), 站内信件

【 在 qaz (请不要在我的肩上哭泣) 的大作中提到: 】
: is most dvd css web page has been taken down.
: I have tried some of my old link. they all been taken down
:
: do search of dvd css yourself ba.

Everything is still in the livid mailing list archive.
http://livid.on.openprojects.net

--
Keine Regel, ohne Ausnahme.

※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 128.148.44.145]
发信人: ayanami (天地无用), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Wed Dec  1 16:40:33 1999), 转信

search for dvd encryption (decryption) on slashdot.org
There were some big discussion around it.

【 在 qaz (请不要在我的肩上哭泣) 的大作中提到: 】
: 【 在 potato (potato) 的大作中提到: 】
: : qaz,  could you provide some resources (articles,website,etc) on this
: : issue? 
: :
: : It might be a good topic for my project
: :
: I read it from some web page before. the problem
: is most dvd css web page has been taken down.
: I have tried some of my old link. they all been taken down
:
: do search of dvd css yourself ba.


--
You are always gonna be my love
Itsuka dareka to mata koi ni ochitemo
I'll remember to love
You taught me how
You are always gonna be the one
Ima wa mada kanashii love song

※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 192.55.120.53]

[返回]
赞助链接
未名交友
将您的链接放在这儿
 

Site Map - Contact Us - Terms and Conditions - Privacy Policy

版权所有,未名空间(mitbbs.com),since 1996