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enter image description heresymmetric key cipher (block or stream cipher) providing partial decryption of data at some points. Although the entire data has not been decrypted, the data decrypted to that specific point should be viewed or accessed.

The partial decryption keys can be inherited form the main symmetric key to do partial decryptions successfully.

Can anyone refer to me any good stuff or papers worked out in this area?

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  • $\begingroup$ This won't allow streaming in the forward direction, but you could use a forward-secure stream cipher. ​ ​ $\endgroup$ – user991 May 4 '16 at 3:37
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    $\begingroup$ I actually remember reading something like this, specifically in regards to compressed video, the least significant bits of quantized data were encrypted so a key was required to unlock the quality $\endgroup$ – Richie Frame May 4 '16 at 5:06
  • $\begingroup$ I dont even want live-streaming ... but of-course the streaming of video upto the point which is supported by the key. Is there any stream or block cipher whose decryption key inherits keys which can be used for partially decrypting data from specific point to point along the length of data? but with the condition that partially decrypted data can effectively be viewed like in case of video... $\endgroup$ – Fawad Khan May 4 '16 at 8:12
  • $\begingroup$ Would it be suitable for you to do: $E_{K_1}(K_{S_1})||E_{K_2}(K_{S_1})||E_{K_3}(K_{S_1})||E_{K_{S_1}}(DATA)$ with appropriate choices of omitting the prepended encryptions of $K_{S_1}$ for the specific parts? $\endgroup$ – SEJPM May 4 '16 at 11:35
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    $\begingroup$ @ SEJPM , Ricky Demer I have added a new more refined post what I want to have. the link is...crypto.stackexchange.com/questions/35084/… $\endgroup$ – Fawad Khan May 5 '16 at 2:41

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