an asymmetric (e.g. public-key) cryptosystem, based on modular exponentiation with big exponents and modulus. RSA can be used both for signature and encryption.
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Breaking RSA, given a special kind of oracle that decrypts related ciphertexts for us
Let $c=E^{RSA}_{e}(w)$ be the ciphertext belonging to the plaintext $w$ if an $RSA$ system is used. Assume that the public exponent $e$ satisfies $e \le 10$. Furthermore, assume there is an oracle ...
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1answer
45 views
chaining rsa with ecies
In an answer to a previous question it was suggested that one way to protect your asymmetrically encrypted AES-256 keys, from say a solution to prime factorization, would be to chain asymmetric ...
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1answer
78 views
inverse of 985 mod(φ60131)
Alright Ive been working on this one for a while
I found φ(60131) to be 97294
½(60131+60131(5)^.5) = 97294
then I worked through the GCD
...
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1answer
218 views
What is the correct value for “certainty” in RSA key pair generation?
I'm creating an RSA key pair in Bouncy Castle and need to specify an int value for certainty. This Stack Overflow answer says it is a relative test for how prime the values are.
There is another ...
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1answer
48 views
Certificate == signed public key
For primes p and q used to create a keypair, I understand that the following operation is used to create a signature :-
M ^ d (mod N)
where d and N have their usual meanings and M is the message. In ...
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1answer
46 views
Solving congruences using PARI
I'm having trouble finding info in the docs about how to solve a system of congruences. The closest I can find is 'matsolvemod' in here: ...
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1answer
90 views
RSA - Ecrypting the same data with the same public key = same ciphertext?
If an adversary knows my public key and guesses what was my plaintext, can he test for it somehow?
The most obvious way is encrypting the guessed plaintext with my public key and the same parameters ...
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1answer
47 views
EC equivalent for RSA-OAEP
I have some questions regarding aforementioned subject:
Is there a EC equivalent of RSA-OAEP key transport/encryption algorithm ?
Is ECIES-KEM sufficient ?
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1answer
279 views
Why the following attack in common modulus RSA works?
Suppose that i share a common modulus $N$ with two users $u_1$ and $u_2$ with public, secret keys ($e_a,d_a$), ($e_b,d_b$).
Why then $gcd(V,e_b)=1$ where $V=d_a*e_a-1/$W and $W=gcd(e_b,d_a*e_a-1)$ ...
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1answer
137 views
What is a trapdoor permutation?
Can anyone explain to me what a trapdoor one-way permutation is? Is RSA a trapdoor one-way permutation?
Context: I was reading about ring signatures. On page 560, it describes steps to ...
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1answer
153 views
RSA 1024bit decryption performance
i want to know how many RSA 1024 bit long key decryption can a regular pentium4 computer do per second ? how to calculate RSA performance and determine its remaining time ?
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1answer
50 views
Design question for a service that signs messages on behalf of a user
I'm working on a messaging service that lets users author messages and have them signed with an RSA key. The key is used for identity purposes only and can be revoked, so compromising the private key ...
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1answer
116 views
RSA Signature - Multiple Use Weakness
I cite from Fundamentals of Computer Security (Chapter 7 on Digital Signature, Paragraph 7.3 on RSA Signatures, page 289):
Multiple uses of the RSA Signature scheme tend to weaken it. The way out ...
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2answers
91 views
Distinguishing Encryption Methods from the Output
Suppose that you see all IP communication packets between two computers for a day, as they pass through a connecting router, and this amounts to 10MB. You additionally know that all data transmission ...
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1answer
135 views
How are the primes used to generate RSA keys?
I am confused about how keys in RSA asymmetric encryption are generated and what the implications for open communications are. Textbooks say the one-way function is merely two primes (with some ...
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1answer
42 views
Physical Level Encryption
What types of algorithms that are capable of signing a message are out there that run on a physical level, e.g. lacking the infrastructure of a standard PC, no memory, processor or motherboard in the ...
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0answers
57 views
Method and explanation for calculating difference in speed between DES and RSA
Our assignment asks us to convert an RSA speed in bytes per second to a DES speed in bytes per second. Our professor's treatment of this ("RSA is 100 times slower than DES") seems insufficient. Could ...
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0answers
36 views
Is it possible to determine the group order by knowing the “public” and “private” key exponents in an RSA group?
I have an RSA group with modulus $n = p \cdot q$, two safe primes $p=2p'+1$ and $q=2q'+1$ and the "public" and "private" key exponents $d$ and $e$. $\phi(n) = 4p'q'$ is the order of the RSA group. If ...
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71 views
Strong RSA problem in $\mathbb Z^*_{n^2}$
Comparing to this question, assume $C, M \in \mathbb Z^*_{n^2}$, $e \ge 3$, is it hard to compute $M$ that satisfies $C=M^e \mod n^2$ when $C$ and $(n, e)$ are given?
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1answer
42 views
RSA Certificate Owner and Issuer line meanings?
Apologies if this question is not in the right place.
I've recently been looking through some RSA certificates ( specifically, Android apk .rsa files) and I'm having trouble deciphering the one and ...
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0answers
81 views
RSA and One Time Password (OTP) service
What is the expert cryptographic opinion on the following?
Assume that there is a web server and a client on web page.
User on the Client calls an OTP web service on the server which
a) creates a ...
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0answers
47 views
How compute encrypt and decrypt runtime for agorithm [closed]
I programming RSA algorithm is the following two function in java language in my thesis
...
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0answers
77 views
Factorize RSA knowing several N and E
I did a CRT challenge yesterday and there`s one problem I was unable to solve, probably due to my lack of understanding advanced crypto math.
It`s about RSA. There are ten given pairs of N and E ...
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0answers
75 views
Actual weakness RSA [closed]
I need modern trends analysis RSA. Hinek books "Cryptanalys RSA and Yan "Cryptanalytic RSA" have been read. What else?
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0answers
118 views
RSA SecurID: Unable to access via web manager [closed]
I'm having an error with access to the web admin of my RSA SecurID server.
I'm getting an error of 100: access denied. The RSA ACE/Server rejected the passcode.
I'm guessing that this is most likely ...
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1answer
88 views
modulus condition [closed]
In RSA algorithm, the modulus $n$ should be chosen based on the below condition
$2^{8(k-1)} \leqslant n < 2^{8k}$
Where $k$ is the byte length of the modulus $n$.
for this condition I want the ...
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1answer
81 views
What length should the padding be when encrypting or signing with RSA?
Does it matter what length the padding is? If so - what length should it be?
(Another point: Should it be random?)
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1answer
63 views
RSA SHA1 signature from public key
Is it possible to generate signature only from Public key. See example below where i have valid signature but what if I change hash ? Is then any way to do this?
Public key(160 bytes):
...
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2answers
468 views
RSA 4096 bit key benchmark
is there any benchmark for RSA 4096bit long keys on general computers ? how many encryption decryption possible per second ? all benchmarks only show 1024 and 2048 benchmarks :(
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1answer
107 views
How can we find Public key have only 8 or 16bits? How many messages does Eve need to know the Public key in RSA?
Suppose Alice sends messages to Bob by encrypting the messages with Bob's public key.
Eve knows that the data is encrypted using RSA, but does not know the public key. Can Eve figure out the public ...
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0answers
62 views
RSA Encryption Sckeme [closed]
Can anyone help me with this question?
A and B want to exchange encrypted messages; specifically, B wants to send a message M
written in binary format to A, which needs to be encrypted. They agree on ...
