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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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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Applications utilizing either $\mathsf{RSA}$ or Diffie-Hellman but not together

What are the applications which utilize Only $\mathsf{RSA}$ but not Diffie-Hellman (applications which can be rendered useless by breaking $\mathsf{RSA}$ alone)? Only Diffie-Hellman but not $\mathsf{...
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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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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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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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649 views

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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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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