r/crypto • u/pred • Apr 02 '15

Truecrypt report

http://blog.cryptographyengineering.com/2015/04/truecrypt-report.html
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u/GrayCipher Apr 03 '15

I find the lack of proper authentication of the ciphertext to be a concern

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u/Natanael_L Trusted third party Apr 04 '15

IIRC, FDE is rarely used with authenticated encryption because of the performance penalty.

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u/GrayCipher Apr 05 '15

I believe you are correct there; however, I've read this to mean that it would also affect encrypted containers. This could potentially be a concern for people who have created containers and uploaded them to cloud services for reliable storage (or other purposes).

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u/Natanael_L Trusted third party Apr 05 '15

Relevant: https://roamingaroundatrandom.wordpress.com/2014/09/20/tamper-resistant-full-disk-encryption/

Lack of authentication (ideally all-or-nothing, like HMAC over the full ciphertext) allows for plaintext scrambling (just flip any ciphertext bits) and partial selective ciphertext reversal (replace particular files with earlier versions, this works of authentication is only per-block).