Score:2

How can I extend the RSA LSB Oracle attack, to n-LSBs?

uy flag

Suppose we have an RSA-Oracle that can encrypt and decrypt our input. The the decryption output is equal to: $ (C^d \mod N) \mod 2^n $.
How can I extend the LSB oracle attack, using the using knowledge about the last n-bits of the plaintext?

fgrieu avatar
ng flag
If think the question assumes an RSA decryption oracle accepting $C$, giving $(C^d\bmod N)\bmod2^n$ for $n>1$; and the Q wants to optimize the number of queries to decipher one ciphertext compared to [this question](https://crypto.stackexchange.com/q/11053/555). Critic: In RSA, encryption is with the public key, and availability of an encrypting oracle follows (and needs not be an assumption as in the Q).
fgrieu avatar
ng flag
Again: the attack with $n=1$ is discussed [there](https://crypto.stackexchange.com/q/11053/555). Also, a never related question is [there](https://crypto.stackexchange.com/q/105976/555). But until it's clarified what the present question asks, I can't be quite sure one is a dupe of the other.
I sit in a Tesla and translated this thread with Ai:

mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.