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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Is 512-bit RSA still safe for signature generation?
The standard CSP on Windows XP only supports RSA up to 512-bit, which means that it's the maximum key size I can use for authenticity verification of updates. The public key is embedded in the ...
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280 views
How exactly are GPG keys mathematically related, and prime numbers inside of GPG general
Before anyone suggest it, I've yet to pick up "Applied Cryptography" I'm planning on picking it up the next time I visit amazon.
I know that the keys are somehow mathematically related, and I know ...
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1answer
188 views
Constructing RSA private key, given public key
As part of a puzzle I was given an RSA 256-bit public key and an encrypted message.
The key itself is very weak, having exponent e = 65537 and modulus N = ...
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66 views
find solutions that solve the equations
I am implementing a timing attack on RSA for school and I need to generate two sets of messages $Y$ and $Z$ for which holds:
$ (Y^d \mod N) \cdot Y < N $ and
$ (Z^d \mod N) \cdot Z > N $
where ...
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209 views
two public keys with same passphrase insecure? | can two hashes be compared?
Suppose someone had generated a 2.048-Bit RSA GPG/PGP key pair and published the public key on the usual key servers. Then he withdraws this key and generates a new one in 4.096-Bit RSA using the same ...
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90 views
It is reasonably safe to leave a SSH private key with a 30+ character passphrase public?
I'm curious about exploring uses for a distributing a single RSA private key with a passphrase instead of trying to secure the private key and distribute the public key. With the private key (and ...
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166 views
Why is RSA encryption significantly faster than decryption?
I am designing an implementation of RSA . I recorded computation times in Java by using System.currentTimeMillis(). It returned an encryption time of 0.05 ms and ...
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1answer
95 views
Does RSA-OEAP have integrity and authenticity properties?
RSA-OAEP is IND-CCA2 secure (indistinguishable under an adaptive chosen ciphertext attack). Does it also have the INT-CTXT (integrity of ciphertext) and INT-PTXT (integrity of plaintext) properties?
...
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108 views
RSA encryption input range - plaintexts that map to ciphertexts?
According to the wiki article on the RSA encryption function, the valid range of input $m$ is $0 \leq m \lt n$. However I have found that the following values of $m$ always return themselves when ...
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496 views
ABC Conjecture's Impact on RSA Encryption
A recent proof of the ABC Conjecture has been released by one Shinichi Mochizuki. Now, I'm not well versed in mathematics but it would appear that this proof implies that finding prime factors could ...
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538 views
Why DSA cannot be used for encryption?
Here it is mentioned that DSA cannot be used for encrypt. But Both RSA and DSA can be used to generate public and private keys, right? (Or am I wrong?). Then why can't I use the DSA public key to ...
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230 views
What algorithm does PGP use to encrypt email?
I know it uses RSA/DSA to create keys, but does it use that same algorithm for the actual cipher?
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Why is the following RSA PRNG cryptographically secure?
One requirement states that the generator has to withstand the next-bit test.
Consider the following PRNG, where we calculate next output $x_i$ via the formula
$x_i = x_{i-1}^ e\mod n$.
I can see ...
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323 views
What is the length of an RSA signature?
Is it the same as the bits of the key (So a 2048 bit system will yield a 2048 bit signature)? At most as the key? Or something else entirely?
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238 views
How to jusify {e,n} is a valid RSA public key?
I have a two set of key {36,77} and {50,117},
How can validate if it is a valid RSA public keys?
Is there any simple method?
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123 views
Idea for secure password hash-likes, is this feasible/usable/workable?
(Hand moved from stackoverflow.com,due to suggestion)
Since breaking password hashes has become a new passtime for scriptkiddies, I thought of the problem and came up with a novel(?) idea.
store ...
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2answers
175 views
One-way function and factoring
I am confused about the hardness of the one-way function behind cryptography -- if someone could factor the large number produced back into two primes quickly then the one-way function would be ...
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3answers
301 views
RSA finding the inverse of the public exponent
I have a very basic doubt in RSA key generation and its usage.
In RSA key generation you choose two large prime numbers of a very large order. Then you multiply them.(eq $p \cdot q = N$) Now, ...
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401 views
How do I derive the time complexity of encryption and decryption based on modular arithmetic?
I want to calculate the time complexity of two encryption and decryption algorithms.
The first one (RSA-like) has the encryption
$$ C := M^e \bmod N $$
and decryption
$$ M_P := C^d \bmod N. $$
...
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1answer
61 views
Is there a big RSA Data Set
Is there a big dataset containing RSA public $(n,e)$ and private keys $d$ and primes $p,q$ where $n = p.q$ ?
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225 views
Is it possible to use the RSA algorithm, or a variant, for software licensing?
I'm almost a newbie about RSA encryption, so my question could it be banal.
I'm beginning to create a licensing system for my software.
I need to distribute a crypted license file to many customers.
I ...
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1answer
180 views
“Signing” with public key
For this question, the following caveats and assumptions hold:
There exists a 2048-bit RSA key pair used exclusively for signing/verification
The private key is kept completely private
There exists ...
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99 views
When to prefer exchanging cryptographic certificates over exchanging only public keys?
Let's think of the following case:
A group of peers want to exchange messages with each other. They use public-key cryptography to sign and encrypt messages. Anyone with any name can join the ...
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215 views
My custom handshake
I am a beginner in cryptography and I designed a custom handshake between 2 entities $\rm C$ (client) and $\rm S$ (server) which should meet the following requirements:
Requirements:
The handshake ...
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1answer
65 views
How to learn the first bit of m in padded RSA
Consider the following version of padded RSA encryption, where encryption of $m$ is done by setting $m′ = (0^k~||~r~||~00000000~||~m)$ for a random $r$ (of length 8 btyes = 64 bits) and then computing ...
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51 views
Comprehension question on a signature protocol based on the RSA assumption
We have the following two-party protocol between Alice and Bob. Alice sends messages $m_1, m_2, \ldots \in_R \mathbb{Z}_n^*$ to Bob and Bob signs these values by calculating $v_1, v_2, \ldots \in_R ...
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1answer
85 views
Is this method for exchanging private key using RSA sound?
Bob know's Alice's public key, and he wants to make sure he's connecting to the one which has that key. Furthermore, Alice wants to verify when she gets a connection from Bob who'll give his public ...
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101 views
Is semantic security important in a hybrid cryptosystem?
RSA doesn't provide semantic security when used unmodified, and neither does the commonly used PKCS#1 v.1.5 padding scheme for encryption.
Is this a problem for hybrid cryptosystems at all?
My ...
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1answer
57 views
What is the most secure way to let Alice “input” her private key, transfer it to the server and decrypt the message?
What is the most secure way to let Alice "input" her private key, transfer it to the server and decrypt the message? (Then destroy the private key on the server)
Every connection is using SSL.
...
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1answer
132 views
using Post-quantum asymmetric ciphers instead of RSA
We can't trust RSA to encrypt our Emails so what is best post-quantum cryptography system as alternative for RSA which provide good security and don't be breakable? because McEliece cryptosystem looks ...
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377 views
Decrypt digital signature using RSA public key with openssl
I have a digital signature that was created using the following algorithm: a SHA-256 hash of the body of the message is calculated. It is then signed using an RSA private key and the result is ...
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2answers
748 views
Secure private key storage
I'm developing application in Java that has to store RSA keys in software for foreseeable future (that is, at least 10 years).
The two most common standards of storing private keys are PKCS12 and JKS ...
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172 views
Encryption with private key?
we normally always encrypt by public key and decrypt with private key.
If i encrypt with private key, then its still secure as normal PKI ?
i mean known-plain-text will not take private key on the ...
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136 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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98 views
Proof of batch RSA security
Suppose we have two encrypted messages with two different public key issued from the one server. There is a client who wants to send these to messages to the server.
In the middle there is an ...
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1answer
2k views
Calculating private keys in the RSA cryptosystem
The number $43733$ was chosen as base for an implementation of the RSA system.
$M=19985$ is the message, that was encrypted with help of a public key $K=53$.
What is the plaintext text?
What is the ...
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186 views
What data is saved in RSA private key?
What data is saved in RSA private key in openssl? How to view it?
Wikpedia says these variables are saved.
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1answer
53 views
Is sharing the modulus for multiple RSA key pairs secure?
In the public-key system RSA scheme, each user holds beyond a public modulus $m$ a public exponent, $e$, and a private exponent, $d$.
Suppose that Bob gives his private exponent to other users. ...
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125 views
Is this attack for RSA possible?
$N=p·q$ ($p$ and $q$ are prime numbers), $m_1, ..., m_x$ are the messages, $e$ and $d$ are RSA encryption and decryption exponents, respectively.
I am given $e, m_1, m_1^e, m_1^d, ..., m_x, m_x^e, ...
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160 views
Weakness in using only one RSA key pair for two-way communication?
In Alice/Bob/Cindy terms (EDIT: and with a little more detail):
Alice and Bob have each securely obtained one key of an RSA keypair from a trusted third party. Alice has one key ($e$ and $n$), Bob ...
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117 views
RSA keys finding when messages are known
I have this situation, where, in a game, people send messages to each other (game moves etc...) These messages need to be encrypted, and should only be readable by the destination person. I am using ...
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2answers
2k views
Signatures: RSA compared to ECDSA
I'm signing very small messages using RSA, and the signature and public key are added to every message, which requires a lot of space compared to the actual content.
I'm considering switching to ...
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372 views
RSA Proof of Correctness
Can anyone provide an extended (and well explained) proof of correctness of the RSA Algorithm?
And why is it needed?
I can't say that this or this helped me much, I'd like a more detailed and newbie ...
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1answer
2k views
OTP from Sony BIOS password recover
From Dogbert's blog:
Sony has a line of laptops ("Vaio") which compete mainly in the high value market segments. They implemented a master password bypass which is rather sane in comparison to the ...
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27 views
Generating Polynomials for the MPQS
I'm going to try and eventually factor RSA-100, but my current QS needs a lot of improvement, so I'm going to try and switch over to the MPQS.
I'm a bit confused as to how the MPQS works, which is ...
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76 views
Two untrusted party want to exchange data: how to ensure each one gets the data it needs? [duplicate]
Possible Duplicate:
Two untrusted party want to exchange data: how to insure each one gets the data it needs?
I am trying to come up with what could maybe be a novel algorithm for an ...
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64 views
What is RSA key normalization?
How can I understand the term RSA key normalization? What exactly is done in the process??
Please explain.
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1answer
66 views
Tweaking textbook RSA to make the encryption a Pseudorandom function
Lets say I want to tweak/alter the textbook RSA encryption function to create a pseudorandom function by pre-processing the input.
Suppose I do something simple like add 2 to the input before ...
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risk of attacker decrypting RSA ciphertext without public or private key
As I describe in my previous question I am trying to decide if it's worth it for me to use the Offline Private Key Protocol in creating some long term private archives, instead of just going with a ...
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Possibility of factorisation of rsa modulus due to vulnerability in java implementation code
Below is my implementation of the RSA algorithm. Actually I'm choosing the private key (d) instead of public key (e) and computing the public key.It is working fine but
I want to know if this is a ...
