Re: [閒聊] 一般人真的有需要用到TPM功能嗎?

作者: d8888 (Don)   2021-07-10 20:32:42
: 目前還沒有 TPM based 的 DRM 應用出現
: 至少零星與 TPM 相關的案例都不是用於加解密數位內容
:
: 技術上也沒有任何採用 TPM 理由
: 把加密數位內容的金鑰放入 TPM 更是多此一舉,沒有任何好處
我本業不是資訊,TPM 相關的論文沒唸很熟,這只是隨手翻的幾篇。「把 TPM 用在 DRM
」早有人探討了
tinyurl.com/2untt58v
這應該是法律人寫的探討智財權的文章。
In DRM, trusted computing can be used to create sealed storage thereby
preventing the user from opening the file with an unauthorised computer
Sealed storage 可以防止使用者用未授權裝置打開檔案。
原理就之前說的,即使如您所說 TPM 本身不加密。但只要 DRM 應用程式自己加密,把金
鑰存在 TPM 晶片裡,然後 TPM 限制只有官方軟體可以取出金鑰來解密,那就能做 DRM。
官方軟體不進行解密(你沒有付錢、官方註銷你帳號、etc.)或 TPM 拒絕提供金鑰(偵
測到環境不符合、被竄改 etc)檔案就是鎖死。
or remote attestation whereby the system generates a certificate of
authenticity of the software running on a computer. In this form of DRM,
companies providing the software can keep a regular check on tampering of the
software by users and can also identify any unauthorized changes made to
the software in order to circumvent TPMs
TPM 可以讓 content provider 遠端驗證本機執行環境,TPM 對本機做了某種掃描,數位
簽章後送到遠端解密。你用破解版或非官方軟體理論上對方能抓到。你沒辦法取出 TPM
內的關鍵金鑰或偽造關鍵數位簽章,你就沒辦法模仿 TPM 的認證和簽名。
Therefore, even after having sold the product for a hefty price, the content
provider can exercise control over how and to what degree can a user can make
use of the bought content. In short, trusted systems have the capability to
be an 'extraordinarily effective and profitable means of controlling, and
rationing, access to works of information and entertainment
這段應該講的很清楚明白。
為什麼 TPM 和信賴運算能作到文中講的事情?
純軟 DRM 的時代,使用者破解了軟體,高手寫第三方客戶端冒充官方軟體,不保證偵測
的到,所以 TPM 給了 remote attestation。
純軟 DRM 的時代,再怎樣花式加密,只要解密的過程金鑰曾一瞬間存在 CPU/RAM 裡,它
就能被高手打撈出來。所以 TPM 給了 sealed storage,東西存在裡面 CPU 也訪問不到
,消費者有控制權也沒用。
如果覺得法律人寫的文章不算,那隨便引個 IEEE
https://ieeexplore.ieee.org/document/8989842
TPM is the root trust module to establish security and trust in digital
computing, communication and networking. Basically, it can support secure
booting and trustworthy software installation, private data protection and
Digital Rights Management (DRM), as well as remote attestation- based trusted
communications and collaboration
細節的部份不重複展開,但文章就是說 TPM 可以拿來做 DRM,DRM 就是 TPM 的用途之一
再引個 Richard Stallman 寫的東西
https://www.gnu.org/philosophy/can-you-trust.html
Of course, Hollywood and the record companies plan to use treacherous
computing for "DRM" (Digital Restrictions Management), so that downloaded
videos and music can be played only on one specified computer. Sharing will
be entirely impossible, at least using the authorized files that you would
get from those companies. You, the public, ought to have both the freedom and
the ability to share these things. (I expect that someone will find a way to
produce unencrypted versions, and to upload and share them, so DRM will not
entirely succeed, but that is no excuse for the system.)
史托曼把信賴運算 Trusted Computing 稱為背叛運算 treacherous computing。信賴運
算就是可以拿來做 DRM。他文章中關於 sharing 的理念對錯是一回事,但至少文字可以
說明 trusted computing 可以用來 enforce DRM
會覺得「TPM 跟 DRM 沒有關係,TPM 不是拿來做 DRM 的」,我認為可以換套關鍵字,並
且回溯歷史脈絡看問題:你用「信賴運算 trusted computing」搭配「DRM」找東西,就
能找到資料了。
我合理推測是 Trusted computing 原來的吃相太難看(我在 2005 年讀資料留下的印象)
,所以廠商換了套說詞,不要提到保護智慧財產權,說保護使用者的資料安全,使用者就
不會排斥了 XD,然後等 TPM 跟 DirectX 一樣普及....
早期的文獻還是把發展脈絡留了下來
不然找 Treacherous computing 也行,東西寫更白了 XDDDDDDD

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