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 Dec19 comment Double Encrypting with two different keys Is the first user doing anything other than decrypting the key? What's user 1 doing in the 90 minute session and how can he do this if he doesn't have the full key to log in? Dec18 comment Individual bits of Textbook RSA @DavidCash Now I see! Thank you for your patience in showing me! Dec18 awarded Scholar Dec18 accepted Individual bits of Textbook RSA Dec18 awarded Supporter Dec18 awarded Teacher Dec18 comment Double Encrypting with two different keys Well, there would be no significant increased security(for brute force attack) than just using the stronger scheme alone. Dec18 revised Double Encrypting with two different keys added 2 characters in body Dec18 answered Double Encrypting with two different keys Dec18 comment Individual bits of Textbook RSA @DavidCash Got it. I see why it's not provably secure. At the end of the day though, were we able to show that each bit is a hard core bit would this not be a secure scheme?It leaks the Jacobi of $r$ but here $r$ is not the message and the only way to distinguish two messages is to recover a bit of $r$. The jacobi of $r$ leaks nothing about $m$. Yes by releasing the Jacobi of $r$ we are limiting the values that $r$ can take on, but only by a constant factor and a ppt adversary would not be able to check all valid $r$. Dec17 comment Individual bits of Textbook RSA @DavidCash Thanks-you. To answer my original question then, none of $m$ can be recovered? So this would imply that if we apply RSA to a random $r$ then under RSA Assumption, no bit of $r$ can be recovered. And we can achieve IND-CPA PKE by using $r$ as in the one time pad--$r \space xor \space m$. This is a simpler scheme than any secure-RSA schemes i have seen, so I was skeptical. Dec17 comment Individual bits of Textbook RSA If every bit is hardcore then how could it leak a bit of information. And what exactly is this information that it is known to leak? Dec17 revised Individual bits of Textbook RSA added 2 characters in body Dec17 awarded Student Dec17 awarded Editor Dec17 revised Individual bits of Textbook RSA added 181 characters in body Dec17 asked Individual bits of Textbook RSA