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DVDEncryption

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: fencer (秋天的树), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Tue Nov 23 12:41:13 1999), 站内信件

【 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.        

--

The fountain of death makes the still water of life play.

※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 35.9.24.111]
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: blueatlas (77), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Tue Nov 23 12:53:28 1999), 站内信件

那么真正意义上的硬拷贝,也是直接可行的了?
【 在 qaz (请不要在我的肩上哭泣) 的大作中提到: 】
: 【 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: 】
: :                   ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
: :                   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: 194.7.240.10]
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 13:04:14 1999) WWW-POST

【 在 blueatlas (77) 的大作中提到: 】
: 那么真正意义上的硬拷贝,也是直接可行的了?
yes. but nobody is produce this kind of hardware.

the real meaning of dvd decryption is that. every one can produce
a dvd player without paying license fee. you used to apply for
a key. and there are limited number of keys.

--
※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 206.75.92.37]
发信人: blueatlas (77), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Tue Nov 23 13:23:01 1999), 站内信件

那么对于盗版事业来说
重要的就是制造出可以硬拷贝的机器,然后大批量硬拷贝。
其次就是,破解解码密匙,非法生产dvd放映机
【 在 qaz (请不要在我的肩上哭泣) 的大作中提到: 】
: 【 在 blueatlas (77) 的大作中提到: 】
: : 那么真正意义上的硬拷贝,也是直接可行的了?
:  yes. but nobody is produce this kind of hardware.
:
: the real meaning of dvd decryption is that. every one can produce
: a dvd player without paying license fee. you used to apply for
: a key. and there are limited number of keys.


--
※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 194.7.240.10]
发信人: qili (qili), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Tue Nov 23 13:29:21 1999), 站内信件

【 在 blueatlas (77) 的大作中提到: 】
: 那么对于盗版事业来说
: 重要的就是制造出可以硬拷贝的机器,然后大批量硬拷贝。
: 其次就是,破解解码密匙,非法生产dvd放映机

the first one is more realistic, and of lower cost. One
has to be able to buy a DVD pressing machine somewhere, and
anything after that is like pressing CDs - close to zero
marginal cost, pure profit.



--
※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 206.189.24.8]
发信人: blueatlas (77), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Tue Nov 23 13:32:37 1999), 站内信件

如果这么说,亚洲地区的DVD盗版就一定会兴旺
盗版篇的兴旺,就预示着DVD机器的市场膨胀
估计就算给那个委员会交钱买密匙,生产销售也会发财
如果自己解决不需要交“保护费”自然就会在中国此起彼伏地出现大量生产厂家
【 在 qili (qili) 的大作中提到: 】
: 【 在 blueatlas (77) 的大作中提到: 】
: : 那么对于盗版事业来说
: : 重要的就是制造出可以硬拷贝的机器,然后大批量硬拷贝。
: : 其次就是,破解解码密匙,非法生产dvd放映机
: the first one is more realistic, and of lower cost. One
: has to be able to buy a DVD pressing machine somewhere, and
: anything after that is like pressing CDs - close to zero
: marginal cost, pure profit.


--
※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 194.7.240.10]
发信人: gesundheit (gesund), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Tue Nov 23 13:44:09 1999), 站内信件

【 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..

This is not accurate.  Almost all the keys are found.
Five of them in totall.  The player key is just 40bit
and the encryption is just two LFSRs(linear shift feedback regiser).
An exhaustive search can be done on a PC.
Some smart ways of guessing the initail state of LFSR1
spead the cracking process up and it's done seconds.

All the keys are in the css-cat package.
They are still there.

:      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.        

The CSS is indeed crapy. :-)  Because it's cracked within
a week with the algorithm known.
--
Keine Regel, ohne Ausnahme.

※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 128.148.44.167]
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 13:45:43 1999) WWW-POST

【 在 blueatlas (77) 的大作中提到: 】
: 那么对于盗版事业来说
: 重要的就是制造出可以硬拷贝的机器,然后大批量硬拷贝。
: 其次就是,破解解码密匙,非法生产dvd放映机

I think . hard copy is difficult. but once you can decrypted data.
you can easily copy it. and you no longer limited
in dvd.
one  can get the unencrypted dvd data and store it into other format
or media. say, china goverment is pushing svcd.  chinese pirated
factory can produce svcd with high quality.

before the decryption. you can only get low quality copy of
dvd.



--
※ 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 13:50:19 1999) WWW-POST

【 在 gesundheit (gesund) 的大作中提到: 】

: This is not accurate.  Almost all the keys are found.
: Five of them in totall.  The player key is just 40bit
: and the encryption is just two LFSRs(linear shift feedback regiser).
: An exhaustive search can be done on a PC.
: Some smart ways of guessing the initail state of LFSR1
: spead the cracking process up and it's done seconds.
:
: All the keys are in the css-cat package.
: They are still there.

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.

--
※ 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 13:54:54 1999), 站内信件

【 在 blueatlas (77) 的大作中提到: 】
: 那么对于盗版事业来说
: 重要的就是制造出可以硬拷贝的机器,然后大批量硬拷贝。
: 其次就是,破解解码密匙,非法生产dvd放映机

You have to know the data format on the dvd disc.
There are some extra stuff per sector that is not
read by a dvd ROM but the standalone players utilize
the extra data on the encrypted sectors directly,
while on a computer this is done by the dvd rom
interface commands.

On other minor problem, the DVD interactive features
are all based on sector numbers.  All the sector numbeing
has to be preserved if you don't want to redo the authering.
--
Keine Regel, ohne Ausnahme.

※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 128.148.44.167]
发信人: blueatlas (77), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Tue Nov 23 13:58:22 1999), 站内信件

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
【 在 gesundheit (gesund) 的大作中提到: 】
: 【 在 blueatlas (77) 的大作中提到: 】
: : 那么对于盗版事业来说
: : 重要的就是制造出可以硬拷贝的机器,然后大批量硬拷贝。
: : 其次就是,破解解码密匙,非法生产dvd放映机
: You have to know the data format on the dvd disc.
: There are some extra stuff per sector that is not
: read by a dvd ROM but the standalone players utilize
: the extra data on the encrypted sectors directly,
: while on a computer this is done by the dvd rom
: interface commands.
: On other minor problem, the DVD interactive features
: are all based on sector numbers.  All the sector numbeing
: has to be preserved if you don't want to redo the authering.


--
※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 194.7.240.10]
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: 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 15:18:26 1999) WWW-POST

【 在 gesundheit (gesund) 的大作中提到: 】
: 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
To use your frame work to explain. D can be find without P
using a algorithm. a PIII450 only need 18sec to calculate it.


: 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.


--
※ 来源:.The unknown SPACE bbs.mit.edu.[FROM: 24.65.146.128]
发信人: potato (potato), 信区: ITnews
标  题: Re: DVD encryption mechanism
发信站: The unknown SPACE (Tue Nov 23 21:16:32 1999) WWW-POST

qaz,  could you provide some resources (articles,website,etc) on this issue? 

It might be a good topic for my project



在 qaz (请不要在我的肩上哭泣) 的大作中提到: 】
: 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: 129.186.118.158]
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 (Wed Nov 24 11:04:34 1999) WWW-POST

【 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.

--
※ 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 (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]

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