Questions tagged [public-key]
An asymmetric cipher is an encryption scheme using a pair of keys, one to encrypt and a second to decrypt a message. This way the encrypting key need not be kept secret to ensure a private communication. Similarly in public key authentication, the verification key can be public and the signing key private.
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Encryption scheme that requires fewer keys for decryption than for encryption
I want to attempt creating a decentralized dead man's switch, so I'm looking for an asymmetric encryption scheme, with the following properties (ideally), or something close to them:
There is a group ...
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1answer
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Combine signature with encryption
I have some embedded device for which I want to sign and encrypt firmware files. Firmware updates are generated by me and may be installed by the customer. The encryption is supposed to protect the ...
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1answer
27 views
Vulnerability of low value generated key
I have read here that Elgamal is resistant to brute-force attack, because the group to where the key is selected is very large. But since the key generation is random, (i assume)there is a chance that ...
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How to identify cryptocurrency used by the public key of the recipient?
I though that it would be an easy task, but I can't seem to find any online resource to help me with it. Say, if I have a cryptocurrency key of the recipient, how can I tell the name/type of the ...
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How to implement EC public key encryption [closed]
I've been studying asymmetric algorithm and trying to encrypt an EC public key, to work just like RSA. found out possible schemes with ElGamal or IES, but the implementation methods I found are not ...
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Homomorphic Public/Private Key Encryption Scheme for Floating Numbers
Is there any public/private homomorphic encryption scheme that directly works on floating numbers or vectors of floating numbers?
In our application, we want to find out if
$$v_1 \approx v_2, \qquad\...
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Sign Verify problem by provider in JCA [migrated]
I'm trying to sign and verify my data with SHA256withRSA,MD2withRSA,SHA1withRSA,SHA512withRSA modes. My provider supports all of them but, just MD2 mode works for my code. Other ones does not work, ...
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ECDSA Public key recovery [migrated]
Helo,
I try to recover the public key from cookie, here is what i've done, not sure if thats correct...
1) Register and login to get the cookie:
...
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1answer
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How do I interpret the CADO-NFS output for discrete logarithm calculation in GF(p)?
I'm using CADO-NFS to calculate discrete logarithm in a finite field GF(p). The problem is when I type
...
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1answer
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Paillier Private $\mu$ and $\lambda$
The Paillier CryptoSystem has a public key that $(g,n)$ and the private key which can be exclusive to $\lambda$, where the decryption scheme is:
$m = L(c^\lambda \ mod \ n^2)/L(g^\lambda \ mod \ n^2)\...
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1answer
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Attacking any one in many public keys
The problem of finding private key from public key is typically studied in the one-key setup: what's the expected cost of breaking one key (e.g. by factoring a public modulus, or solving a discrete ...
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What are some use cases for white-box digital signatures?
There were 2 papers published in the last year, that describe 2 different white-box identity-based digital signature schemes:
White-Box Implementation of the Identity-Based Signature Scheme in the ...
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In ring LWE, I need to encrypt an integer.it is resulting in 8 integer.size grows enormously.how to control this? [closed]
In ring LWE, I need to encrypt an integer.it is resulting in 8 integer.size grows enormously.how to control this or where I got stuck up?
Eg.
For encrypting take value=5
Encryption:
Convert to bits:...
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Openssl DSA Signature Verification Failure Error not understood [migrated]
I am given a public key in PEM format:
...
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0answers
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Can hash functions be used for asymmetric encryption? [duplicate]
Snuffle uses hash functions but it is symmetric key encryption. Can a hash function be used to let a client encrypt without knowing the private key, and the server decrypt using a private key?
https:/...
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2answers
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Why is RSA encryption performed in mod n, but computation of inverse in $\bmod \varphi(n)$
I am studying the principles of RSA and have come across some unintuitive statements. Lets revisit the RSA algorithm:
RSA Key Generation
Output: public key: $k_{pub} = (n,e)$ and private key: $k_{pr}...
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1answer
36 views
Is it possible to calculate the random factor r from a encrypted message and the private key in a paillier cryptosystem?
I have already done my research and found various sources that state that it is possible but there are also a lot of them that says it is not possible to recover $r$, this for example even states the ...
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In search of a pedagogically simple example of asymmetric encryption routine?
(I am not a cryptography expert; I do write software)
I am working with some youth (ages 11-13) and wanted to explore for an hour or so some basic cryptography. Doing symmetric ciphers is pretty ...
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Are the existence of secure IBE and secure PKE equivalence?
Of course, if there is a secure IBE (e.g. IND-ID-CPA), then there exist a secure PKE (e.g. IND-CPA).
I want to know the inverse proposition is true or not.
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Do I need to use a matrix of size N x n for the public key in the BGV scheme when using Ring-LWE?
I'm going through the BGV paper and trying to make a toy implementation, but I just want to focus on Ring-LWE. In the paper, they set $N = \lceil{(2n + 1)\log_2(q)\rceil}$, and generate $A'$ uniformly ...
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Perfect secrecy public key scheme [duplicate]
Are there public key schemes that have perfect secrecy? The perfect secrecy notion is defined for symmetric key encryption. If P is a message and C the corresponding ciphertext then the cipher has ...
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1answer
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How are blockchain keypair private keys hidden from miners, and how are they generated in the first place? [closed]
I don't know how blockchain keypairs are programmatically generated, and equally important - how they are able to verify their keypair using a private key to a remote server - while keeping their ...
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1answer
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What is Reverse Trapdoor Function?
In wikipedia on Digital_signature:
but rather, the message to be signed is first hashed to produce a
short digest, that is then padded to larger width comparable to N,
then signed with the ...
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The security level of double encryption
Let PKE $\Pi' = (Gen', Enc', Dec')$ and it is secure in the sense of $S'$.
Let PKE $\Pi'' = (Gen'', Enc'', Dec'')$ and it is secure in the sense of $S''$.
$S'$ and $S''$ may be separation which ...
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1answer
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How are precision and security related in a Gaussian Noise Sampler for R-LWE?
My understanding is that the sampling precision in Gaussian Noise sampler is related to security. But not sure about why is that? I read that when the samples are floating-point numbers and precision ...
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asymmetric encryption with rekeying in an untrusted environment
Alice can retrieve asymmetric encrypted messages (let's call one of them C1 and the Message itself M) for her from an untrusted environment (let's call it Eve). She owns her private key K1 and has ...
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Is using different public keys for different peers safer than reusing the public key, beyond forward secrecy?
In X25519 (ECDH over Curve25519) Peer A and B exchange their Public Keys ...
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1answer
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Deterministic procedure for mapping an arbitrary value into a 𝑝,𝑞 pair for pubic key cryptography
I want public key cryptosystem to used for re-encryption as describe in Can Paillier ,RSA or any other schemes be used for universal re-encryption like elGamal?
Now i have little solution for ...
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1answer
49 views
Can Paillier ,RSA or any other schemes be used for universal re-encryption like elGamal?
ElGamal, RSA, and Paillier cryptosystem have homomorphic property, and can be used fro re-encryption purposes. I want to use the encryption to re-encrypt ciphertext(as in proxy re-encryption but ...
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Can Paillier Encryption has independent decryption key?
As Pailliear cryptosystem secret key $\lambda$, depends on primes $p$ and $q$. As $\lambda = \operatorname{lcm}(p-1,q-1)$.
I want decryption key to independent from $p$ and $q$.
It can be possible ...
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1answer
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How Paillier cryptosystem can be used practically to encrypt and decrypt big messages “m”?
I want to use the Paillier cryptosystem for encryption and decryption purposes in my research work. But i haven't found a way to encrypt big input messages;
As i want to encrypt the message i,e m :
<...
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1answer
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Is there any relationship between Paillier Cryptosystem's random r and other factors
I want to try run an example of Paillier cryptosystem(Algorithm), So i just started with some basic examples, but cannot obtain correct result/decryption.
I just change random factor ...
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1answer
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Multiple sender single receiver Encryption
I had this article given to me by my teacher, and I would like to enhance it.
It's titled Modified El Gamal Algorithm for Multiple Senders and Single Receiver Encryption.
I planned on having the ...
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2answers
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What is the difference between “asymmetric key cryptosystem” “asymmetric cryptography” terminology?
What is the difference between "asymmetric cryptography" and "asymmetric key cryptosystem" terminology?
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1answer
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How re-encryption can be done through RSA
Both RSA and Elgamal have homomorphic properties. So both can re-encrypt the ciphertext. Re-encryption with Elgamal works as seen here.
How does re-encryption work using RSA?
What modification / ...
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How do I calculate key rotation schedules?
tl;dr: How do I formulaically determine key rotation schedules for different kinds of keys and use cases?
The organization I'm a part of for utilizes both symmetric and public/private key encryption ...
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0answers
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Is it possible to construct a hash-based public key encryption scheme? [duplicate]
I know hashes can be used to construct symmetric encryption schemes (HMAC running in counter mode), signature schemes (SPHINCS), pseudorandom generators, etc.
One thing that's missing is public key ...
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1answer
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NaCl allows decryption with the same public key as for encryption
I followed the description here:
Public-key authenticated encryption: crypto_box
and created an example that encrypts a message with Bob's public key and signs it with Alice's secret key :
...
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0answers
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Is it possible to verify attributes of encrypted content?
Let's say that Alice has this information about her,
{ "name": "Alice", "age": 25, "eyes": "brown" }
which she encrypts with a key pair so that no one access ...
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2answers
76 views
Using public-key signature instead of having API key
I am designing an application that will need an API key. At first I believed that generating a long, random token would be secure enough (say 32 chars string that includes 0-9, a-z and A-Z), and then ...
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1answer
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Can't understand the magic of relationship between private an public key functions
To encrypt a message
$$
P = 53, Q=59, n=PQ=3127, e =3
$$
let message M, for example, $ 89
$$
cipher = 89^{e}mod\quad n.
$$
cipher = 1394 this is the encrypted message
$$
\phi=(P-1)(Q-1)=3016
$$
$$...
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1answer
57 views
Is there a zero knowledge proof to show an encrypted blob is the key for a given public key?
Let's say I have a private key x with a corresponding public key y. If I encrypt x as ...
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1answer
142 views
Could public-key crypto be performed long ago if the idea had been discovered?
Public-key cryptography was not invented until the 1970's. Apart from the idea not existing earlier (as talked about here), is there any reason it could not have been used earlier? For example, are ...
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2answers
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Discrete logarithms on elliptic curves
In many examples of attacks on public key cryptography, examples of the form $a ^ x = b$ are used, but I can not understand the correlation between this and the multiplication of the generator point ...
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aspnet_regiis private key storage
I am using aspnet_regiis.exe to Encrypt a connectionStrings on an ASP.Net application. The application in productions runs on a <...
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1answer
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P256 Key size and validation [duplicate]
Given a public key on the P-256 Curve is it correct to say that the public key is 64 bytes long ie. (x,y)?
Secondly is the private key 32 bytes long? if so, how is the private key generated and why ...
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Asymetric encryption, multiple recipients, traitor must share private key
Is there an Asymetric encryption scheme, or public key encryption, where multiple recipients are able to access the data but in order for one of the recipients to leak the key to the data they would ...
2
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1answer
54 views
Where does signing/decrypting take place on a YubiKey 4/5 PIV private key?
I have a YubiKey 4 and want to use it to store a private key that should never enter a computer system's memory. After importing the key to the device I understand it never leaves it. Do the signing/...
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0answers
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A proposal for randomization of Niederreiter cryptosystem
The Niederreiter cryptosystem is a public key cryptosystem using Goppa code. Unfortunately it it is insecure unless it is a binary code. So I thought I could insert random linear codes into randomly ...
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2answers
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Raw curve25519 public key points
I'm trying to understand curve25519, and ECC public points.
I'm playing with Minisign, to better understand the fundamentals of ECC.
Minisign uses curve25519 and outputs public keys as base64 ...
