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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'-in' is an invalid command. [closed]

While trying to convert private key into public key i get this error message. I used "openssl genrsa -des3 -out private.key 4096" to generate the private key and used "openssl -in private.key -...
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How to find “k” in system of equations?

This is a $y^2=x^3+7$ elliptic curve points - $Q,G_1,G_2,G_3. k_1,k_2,k$? - secret exponents: $k_1*G_1( x_1,y_1) = Q(X,Y)$ $k_2*G_2( x_2,y_2) = Q(X,Y)$ $k*G_3( x_3,y_3) = Q(X,Y)$ How to find a $k$?...
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Are there alternative ways to decrypt the public key to the public address

I've read and I discovered that it's not possible to derive the public key from the public address because of the hashing algorithm.... But is/are there any alternate way/ways that it can be ...
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How to recover RSA messages if they are padded with spaces?

I have a message m="hunter". Let's say we pad it with 2 spaces from the left making the final message as ...
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Is there a library that implements the “Mickey Mouse Version” of asymmetric cryptography?

Here is what I mean with "Mickey Mouse Version": CHARLIE makes a keypair key1 and key2 ...
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Creating multiple “public” keys from one private key

Is it possible to create a public key out of a private key, then create another public key from the first public key. And treat the first public key as a private key (So you have two levels of private ...
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Can duplication of encrypted characters lead to a weakness in RSA?

Of course, I know RSA is to widely used and tested to have any legitimate threats, but I still am confused by this. I have been trying to implement C++ (in a effort to learn how it works, not to be ...
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Is it possible to generate random bits to be imported as a private key and then deducing his public key?

Is it possible to generate random bits (or any bits we decide) to be imported as a private key and then deducting his public key please? Ideally with a supported Javascript WebCrypto algorithm ( ...
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Asymmetric Cryptography

I'm new to cryptography and still trying to understand the way an asymmetric cryptography works. Here's what I learned yet - If Bob wants to send Alice a message, Bob will encrypt the message with ...
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542 views

In-browser public key encryption [closed]

Is there any existing website/code that can be used so that the user can do the following all within the browser and without transmitting raw text to any server? Paste in public key Paste in raw text ...
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685 views

How to encrypt video using RSA [closed]

I can encrypt the message using the RSA algorithm. But I do not know how to encrypt video.
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Why does Paillier have poor performance?

Can anyone explain to me why Paillier crypto system does not provide good performance? I read here (pdf) that RSA and ElGamal provide better performance than Paillier algorithm.
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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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How to use public/private keys in elliptic curve cryptography to encrypt/decrypt information

I'm reading a bit about elliptical curve cryptography. The basic idea is to define a dot-operator on the points of an elliptic curve. Given a starting point $P$, and applying this dot-operation $n$ ...
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I am new to digital certificate 509V3 concept. can some one please clarify the below points [closed]

I am using RSA 2048 with SHA 256 primitive in certificate: How to verify the user certificate n + 1 with Root certificate n? why it is required to perform Certificate chain verification? How to ...
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Best way to go about understanding proofs and cryptography in general? [closed]

Studying both symmetric and asymmetric cryptography and having the hardest time doing so. I wanted to ask what is the best way to go about learning proofs? I don't have a strong mathematical ...
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Signing operation with public key in bitcoin protocol (video lecture)

At 5:26 in this princeton coursera course video the presenter says that the public key is used (by the recipient) to generate the signature to redeem the coins. I'm a little confused here. If the ...
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Need Help with understanding authentication process

I want to develop an app which allows to pair between pc using bluetooth then you can send the signal from the phone to unlock the PC(on the same network). I need help with the process after ...
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Store and share data on intranet website

I'm developing an intranet for a company where admins are sharing a huge excel file containing all the necessary password, on the common TSE. I've managed making them encrypt it with a common password ...
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Could someone explain the given algorithm?

The following snapshot of the algorithm is taken from the book Guide to Elliptic Curve Cryptography published by Springer 2004. I don't understand that why at the statement 9.1 if both $T_1$ and $...
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PGP message integrity : How can receiver of an email check the integrity using the sender's public key?

PGP message integrity: Basically, only private key can decrypt message encrypted with public key. But in the message integrity service in PGP does the reverse, where the Hash of the message if ...
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Is size Q equal to size SHA(Q)? [closed]

Assume d is a 128 bit random integer and P is base point of an elliptic curve and Q = dP is a point on the elliptic curve and SHA is a hash function with 128 bit output, my question is: Is size Q ...
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What is your solution regarding PGP? (what software is used?) [closed]

What is your solution regarding PGP? (what software is used?) (Is it simply what kind of program i use, like ”ProtonMail” or ”openkeychain”? Or is it something else?)?? How are your private PGP keys ...
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Storing public key in cookie

I am encrypting my password before sending to my server with a public that i have stored as a cookie. Is there any security risks storing my public key in the cookie? Are there any better ...
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Deterministic procedure for mapping an arbitrary value into a 𝑝,𝑞 pair for public 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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how to encrypt the chat message with multiple people public key together and restore the message?

I have a application with two users and one middle man, all of them holding the private and public key, To make the secured chat, two users and one middle man are all sending the public key and ...
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Simple hexadecimal to 2s complement question

From 2.5.1 in this paper, how is $p$ = FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFF FFFFFFFE FFFFFFFF 00000000 00000000 FFFFFFFF = $2^{384} − 2^{128} − 2^{96} + 2^{32} − 1$ ...
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RSA encryption with private key, decryption with public key (again) [duplicate]

First of all let me point out that I am aware of all the theory behind asymmetric encryption and signing, and other related areas like signcryption, etc. It seems that mathematically it is possible to ...
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What is contained in a RSA key file? [duplicate]

Consider a RSA key file like this: ...
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How can I prove CPA secure by using a new scheme gen,enc,dec from GEN,ENC,DEC?

Given public key encryption scheme $(\mathit{gen}; \mathit{enc}; \mathit{dec})$, we now construct a new scheme $(\mathit{Gen}; \mathit{Enc}; \mathit{Dec})$ as follows: The key generation algorithm $\...
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Is symmetric encryption no longer necessary?

Here is it: Symmetric encryption is no longer necessary, because all security services can be implemented with public-key cryptography. Moreover, in public key cryptography the operations for ...
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What is the advantage of a symmetric encryption system over an asymmetric encryption system?

What are the reasons why somebody would choose a symmetric system over an asymmetric system considering its disadvantage such as a key management and a key transmission? Some people say a symmetric ...
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Non-derivable public key asymmetrical encryption? [duplicate]

The need we have is to pass encrypted messages but such that the encryption key can't be generated from the decryption key. This sounds like with vanilla asymmetrical crypto I know, but in every ...
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339 views

Elliptic curve cryptography for encrypting audio [closed]

I want to use ECC to encrypt audio. Is ECC encryption a stream cipher or block cipher? I'm encrypting one sample (1 byte) at a time and I want to use multi-layer encryption (multi-ECC) to increase ...
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2answers
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question about RSA [duplicate]

I am very new in cryptography field, what I want to ask but I cannot find an answer is this: In public key cryptography, such as in RSA, does it matter if the adversary knows/can detect the public key?...
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If Bob wants to make sure Alice knows a second message came from him, what key or method should Bob use?

If Bob wants to make sure Alice knows a second message came from him (not caring if only Alice can read it), what key or method should Bob use?
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RSA: why does $m^{ed}$ equal the original message?

Trapdoor functions are defined as that a secret key reverses the function. It seems to me more that it causes a cycle to repeat, similar to how $n^k \bmod k$, when $k$ is a prime number, equals $n$, ...
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Can two different CA's/End Entities in different PKI's have the same asymmetric key pair?

Example: $X$ and $Y$ have the same asymmetric key pair. $X$ communicates with $A$ and gives it's PubKey to $A$. So, $A$ has the PubKey of $X$ which also happens to be the PubKey/PrivKey of $Y$. ...
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Diffie-Hellman (Public Key exchange)

I have read a few tutorials in regards to this. My understanding is that Diffie-Hellman is a key exchange concept that is being use everywhere in our daily lives, which is also known as the public-...
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encryption and decryption time for RSA-crt in java? [duplicate]

I try compute execution time for encrypt and decrypt data has 1024 bit = 128 byte in RSA-crt algorithm. I need this results. But I believe this result wrong. because big diffrent between execution ...
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What is the difference between $\bmod{p - 1}$ and $\bmod p$

I have a doubt in my research work, can anyone tell me; What is the difference between $\bmod {p-1}$ and $\bmod p$
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Why are asymmetric keys represented as base 64? [closed]

When one generates a public and private key with say a total of 4096 bits, why does the program output what I assume to be base 64 instead of base 10 or binary?
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What is an example of asymmetric cryptography?

What is an example of asymmetric cryptography or public key cryptography?
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RSA public key security issue

The public key for RSA is $[e,n]$. Since $n = p * q$, are $p$ and $q$ already exposed because it takes no effort to figure out $p$ and $q$ from $n$?
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Can Big Data together with deep neural networks attack RSA by affording the vast calculation of prime multiplications in advance?

This is a spin-off from Can Big Data attack RSA by just calculating many prime multiplications in advance? [duplicate]. Intro I am somewhat new to cryptography. Repeating the basics of RSA from How ...
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Why would an efficient integer factorization algorithm render RSA insecure?

I know that RSA relies on the integer factorization problem: given two primes p and q, their product p . q is easy to compute. But not feasible (i.e., polynomial-time) an algorithm is known that could ...
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List of available symmetric & assymetric ciphers [closed]

I was looking all over the Internet list of ALL existing symmetric and asymmetric ciphers. I know that there's, for example, AES, DES, Blowfish, DSA. But how about more? Where to find such list?
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How to distinguish between private key and public which are visible in text editors?

I would like to know how to understand which one is private key and public key while seeing them in raw text format?
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How exactly does plaintext become ciphertext?

I'm having a hard time finding out how PlainText becomes Ciphertext. I understand that I do the following: PlainText -> RSA/AES/Whatever -> Ciphertext Can ...
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Someone discover two pair privkey for one address

I have a question about bitcoin privkey: If you have TWO pair privkey(compressed and uncompressed) I wrote again TWO pair, yes i know, many person say - it is not possible, but... And this works ...

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