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Does Man-In-Middle attack isn't possible when we use reverse of RSA algorithm in Digital signature?

Yes, anybody can perform modular exponentiation using the public key. This would then result in a padded hash, which would in turn contain the hash. So if an adversary is able to guess the input data ...
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Isn't an asymmetric cipher (like RSA) algorithm sufficient for all basic needs, when speed is irrelevant?

For the same key sizes, symmetric encryption protocols are safer than asymmetric protocols. Informally, the cryptanalysis algorithms used to decipher RSA try to identify the prime values used to ...
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4 votes
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RSA not encrypting properly when e=d?

I believe the problem is linked to the size of the message rather than the choices of $e$ and $d$. When deciphering a message, we don't get the result of the message m but rather m mod N. With $N$ ...
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2 votes

Isn't an asymmetric cipher (like RSA) algorithm sufficient for all basic needs, when speed is irrelevant?

Beware that beside RSA, we don't know many "asymmetric block ciphers" per the question's definition (essentially trapdoor permutations), thus building over this won't allow substitution with ...
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Do RSA powers of two modulus always have MSB set to one and so when DER encoded have 0x00 prefix?

Yes, it is always so, if just because the key size is actually the size of the modulus for RSA. The sizes of the primes that produce the modulus should be selected so that the key size is between $[2^{...
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|RSA| Is it normal for $\phi(n)$ to work as RSA modulus?

In general a pair of RSA decryption exponents calculated in this way for a modulus $N$ will also work for any modulus $M$ that satisfies $\lambda(M)|\phi(N)$ where $\lambda$ is the Carmichael function....
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Sharing RSA private keys using key exchange algorithms like Diffie–Hellman Algorithm?

This is going in the wrong direction, so I'll answer by showing two alternatives: Share e.g. a strong machine generated password for this with enough randomness to pass as a secret key. The reason to ...
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Deducing a secret key from two different public keys

You should take a look at how $p_{k_1}$ and $p_{k_2}$ are derived from $s_k$ (or more concretely how $e_1$, $e_2$ are derived from $d$). Once You understand it, see if there is a way to deduce the ...
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Deducing a secret key from two different public keys

This is a homework question, and so I'll give you a hint, not the answer. The intended approach to take is not to recover $d$ directly; instead, it is to factor the modulus $n$ (and once you have that,...
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5 votes

Would encrypting a message twice with RSA with different keys be more secure that once?

Could someone please explain, mathematically, why I am correct/incorrect? This isn't a mathematical explanation, however I believe it's not a mathematical situation. By performing RSA twice, the ...
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1 vote

Additively homomorphic (modified) RSA?

I tried proving that $E(message_{1} + message_{2}) \equiv E(message_{1}) \cdot E(message_{2})$. Does anyone see where I messed up? It is appeared you messed up when you tried to take this paper ...
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Proving that RSA CCA is possible

The author forgot a few $\bmod n$ along the way. In particular, equation 9.2 is wrong, and should be $$E(PU,M_1)\times E(PU,M_2)\bmod n=E(PU,(M_1\times M_2\bmod n))$$ Also, what follows "note ...
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RSA Algorithm: What are the maximal possible locks that your friend can have so that he/she can secretly share that to you?

CAUTION: There's is something so wrong in the question that it's reasonable to dismiss it, see second section. But first let's try to answer it as if we didn't notice. In one of several slightly ...
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