# 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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### 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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### 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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### 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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### 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?