RSA is a common public key algorithm, which can be used for encryption and signature. It is a core component of most the security protocols used on the Internet, including the SSL/TLS protocol suite.

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Making a bitcoin-like secure mail protocol, how to tackle public keys?

I'm making a new mail protocol (probably already exists, but I've learnt a lot of things about security and privacy on the way). Here's the summary(much simpler if you know bitcoin's inner workings): ...
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47 views

Timing Attacks in RSA

Considering the classic scenario of Eve trying to listen in to Alice and Bob's conversation, if Eve can intercept messages between Alice and Bob but with no access to their computers would Timing ...
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How much time / “entropy collected” should generating a RSA 2048bit keypair take?

The purpose of my question is get an better idea about reasonable amout of time the generation of the RSA public/private keypair should take? To be less vague let me specify the question and define I ...
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502 views

How to secure communication between server application and client mobile application through HSM

We are planning to deploy HSM with our application. The solution we are thinking is : Mobile applications talks to server application, Server application talks to HSM for authentications, ...
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99 views

Can anyone explain how to use an X509 client certificate to securely authenticate a user?

Bit of background. Web Application that can generate Pub/Priv Keys and X.509 certificates. How would I make use of the certificate in a web application, username and password login form to provide ...
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183 views

Import securely RSA private key through PKCS#11

I have a cryptographic device that supports the following mechanisms: How I could securely import RSA private key into it? Because there is no support for wrap/unwrap using symmetric key is there ...
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113 views

Is a Diffie Hellman Ephemeral key good material for being used as a symmetric cipher algorithm key?

I am designing a secure protocol (for academic/learning purposes) and I am at the point where I need to (re)design the key exchange step. In my previous implementation, I used to rely on RSA to ...
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187 views

Can RSA keys be swapped?

On a theoretical level, is there anything inherently different about public vs private keys? During RSA key generation there are two keys generated, key A and key B. Key A is private and Key B is ...
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75 views

Use the same IIS RSA key on all servers

I am working on standardizing our server builds where we currently have three different functional pools. For web pools I use the same IIS RSA key across all machines. It keeps life easy and ...
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77 views

Theoretical key encryption question

I have a question regarding encryption and message sending. There are 2 hosts, A and B with their own secret key kA and kB (assuming this is not PKI). It is known that when A wants to send a message ...
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90 views

Where to offer money for cracking check [duplicate]

I made a software and I would like to distribute it as a demo that can be registered. I would like to know if there is a site where I can offer some reward for some one try to crack my software and ...
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215 views

Questions about RSA/asymmetric key encryption?

I've been reading a lot about quantum computers and RSA. I know RSA security relies on the difficulty of factoring an extremely large number with just two prime factors. Apparently quantum computers ...
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112 views

“Keyset does not exist” when using SignData function with RSA

"Keyset does not exist". I know that there are tons of question about this error, but mine is totally different. I'm not gona use the key from windows certificate store, but load the public key & ...
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362 views

Convert RSA SSH public key file into x509 certificate

I have a RSA SSH public key which I have converted from a x509 certificate and I want to be able to convert the SSH key back into a x509 certificate to compare the values with the original ...
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82 views

RSA key exposure

Is there any limit to the number bytes that an RSA key can be used before it can be exposed. In Symmetric encryption a Key is not recommended to be used to encrypt more than specific amount of data ...
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97 views

Is my approach to anonymous certificate based HTTP(s) authentication and secure private messaging sound?

I'm trying to work out a somewhat anonymous secure messaging system, and was hoping someone could validate my overall approach. Keep in mind, this all takes place over HTTPS. Authentication While ...
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29 views

Secure data with server and RSA? [duplicate]

the RSA system uses a private key to read the content encrypted with the public key. If I make a game for mobile, and want to save the data : I guess I cannot save the private key on the device. If ...
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1answer
182 views

Is the standard scheme of RSA CCA and CPA secure?

I'm looking through old tests in an information security course - and there's a question about CCA and CPA security of RSA. I can't seem to grasp how I'd either show insecurity or prove the security ...
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136 views

What is the excellence of RSA vs my algorithm [closed]

I was wondering that what make RSA Asymmetric Cryptography Algorithm special. So I wrote a very simple algorithm that do the same work (Generate Public and Private Key) Now I want to ask you that What ...
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67 views

RSA encryption confidentiality [closed]

In this scheme , is confidentiality guaranteed? A sends to B an encrypted file which is encrypted by B's public key. Can you illustrate any variant, still RSA- based but also using symmetric ...
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306 views

Why should the dh keylength match rsa length in tls?

A few sources state that the DH keylength (bits of the prime) should match the keylength of rsa for TLS. For example SSL_set_tmp_dh(3) from openssl has example code on how to match the dh parameters ...
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324 views

Help to understand secure connections and encryption using both private/public key in RSA?

I just started teaching myself cryptography, I am reading this http://www.garykessler.net/library/crypto.html to understand the basics. I am confused by Sections 3.4 and 5.3. Section 3.4 details how ...
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104 views

Which part is the longest when gerating RSA key pairs?

Whether I use openssll or gnutls's certtool, I end in a single threaded part which take several minutes. When I try to compile the libraries with auto-parallelizer advanced efficient tools. It sill ...
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714 views

Look over my Web API Authentication Scheme

I want some advice on my Authorization/Authentication scheme that I will be using for my Web API that I am writing. Firstly the Authentication : 1) When a user first logs in and they are authorized, ...
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438 views

RSA key recovery using sound - How does it work?

A very interesting Debian security advisory was released yesterday. Genkin, Shamir and Tromer discovered that RSA key material could be extracted by using the sound generated by the computer ...
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194 views

encrypting a file with an RSA key

I wrote a java program to encrypt and decrypt files using AES algorithm in CBC mode and a random initialization vector. but there is something fundamental I'm not understanding:first I generate a ...
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58 views

Broken/halfbaked security with this implementation?

I'm reading the specification for a commercial product which provides a webservice.The spec goes like this: The client (a webbrowser) may use https Client asks server for info --> gives modulus and ...
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319 views

Authenticate user without knowing their password

I'm working on a project where each each user will have a public/private RSA key-pair. Users will be able to send encrypted messages to each other using the each target user's public key so that only ...
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2answers
186 views

For DHE_RSA_.. Cipher Suites what is RSA used for?

In addition to achieving PFS with DHE, we want as little as possible to be revealed when the server's private key is revealed. So, what is RSA used for in DHE_RSA cipher suites? What does the server ...
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674 views

Are there any holes in this security design?

This design is for transport security between a client and a server. I'm planning on using it for a cloud storage system. I would like it to be secure against you-know-who. I'm trying to prevent the ...
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565 views

What's the limit on the size of the data that public-key cryptos can handle?

Someone mentioned here that asymmetric encryption might not be appropriate for bulk data and gave an example of RSA with 100 bytes. Of course, I understand that it was a rough example. But it made me ...
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Is generating an RSA key with password and then stripping it off more secure than no password at all?

Some time ago I came across this question on SO; it asks how to remove the passphrase from an existing RSA key using a PHP equivalent to the existing openssl rss command. I've posted an answer with ...
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1answer
228 views

Is TLS 1.0 sufficiently secure for a bank?

I disabled SSL2 and SSL3 in my Firefox browser, version 24. I only enabled TLS 1.1 and 1.2. Unfortunately when I went to my bank's website, I found that it didn't work until I re-enabled TLS 1.0. ...
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839 views

Is my RSA signed data secure?

So with all of the FUDD (fear/uncertainty/doubt/disinformation) going around about RSA in light of Snowden leaks and other discoveries about backdoors into PRNG, I'm uncertain what this means to me... ...
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573 views

Which products are affected by NSA's ability to crack pseudo-random-number generator Dual_EC_DRBG? [closed]

After reading this article about RSA advising its customers not to use the default random-number generator in its encryption products - amid fears spooks can easily crack data secured by the ...
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1024-bit DHE vs 2048-bit RSA

Currently with apache/mod_ssl, if DHE is enabled then a 1024-bit ephemeral key will be used. I found the following quote in Adam Langley's blog: Ideally the DH group would match or exceed the RSA ...
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277 views

Does RSA encryption always pad small amounts of data to some larger size?

If I encrypt 160 bits (20 bytes) of data using an RSA 1024 private key, will the result always be 128 bytes? This seems to be the case in my experiements, but I want to be sure. For example, ...
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394 views

How can we trust PKI, for example, Verisign?

We want to send an encrypted message to Alice. We can ask her a public key over the network, encrypt with it a message and send that message back. It is bad, because someone can pretend to be Alice ...
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212 views

Reason for using Asymmetric encryption along with SHA256

I got a document with integration with another application. They mentioned I need to hash and then encrypt data with my private key before sending it over HTTPS. By doing this, they are making sure ...
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163 views

Devising encryption schemes and protocols

I am wondering how encryption schemes are developed and why certain decisions are made. For example. I have seen a company hash a string with SHA1 and then RSA encrypt it. Why? I've also seen the ...
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Designing a cryptographic file-sharing protocol

As a learning project, I am trying to implement a secure way to share files with a friend over dropbox. (I am not looking for existing software, I am doing this in order to learn how to do this ...
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1k views

What is the easiest way for a newbie to RSA to create & use a key pair on Windows?

So I need to get a block of text sent to me over email from a friend, but before he sends it he wants a public RSA key from me. Am wondering what is the simplest way for me as a newbie to generate ...
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4k views

Create RSA public, private key pair having numbers generated already

I want to know to to generate working RSA key pair, with correct syntax. Let's say i have already generated somehow my numbers for 512bit key, which are: e = 00065537 d = ...
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139 views

Deciding whether to sign someones key

How do i decide whether to sign someones PGP public key? I was looking at some contact pages and they have a request for people to sign their public key. How serious of a commitment is it to sign ...
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139 views

Posting public key [closed]

Should I put my public key on my website so that people can securely contact me. I have seen personal sites where there public key is at the bottom of the page such as this site by the computer ...
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1answer
394 views

Does the NSA X-Keyscore apply for HTTPS traffic? [closed]

See X-Keyscore: NSA tool collects "nearly everything a user does on the internet". http://www.theguardian.com/world/2013/jul/31/nsa-top-secret-program-online-data Does anyone have a clue how they ...
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Is a passphrase-protected SSH private key susceptible to a dictionary attack?

If I have a passphrase-protected SSH private key, AND if this passphrase is sufficiently random and long (say, 20-, 30-, 40-characters long, or even more!), AND if I make this private key of ...
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266 views

OpenSSL dgst authentication failure

I've tried to replicate the workflow presented on this blog in OpenSSL: http://farid.hajji.name/blog/2009/07/27/public-key-cryptography-with-openssl/ However, authentication seems to fail despite ...
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234 views

Security of PGP for Long-Term Storage

How secure are PGP/GPG encrypted mails? I realize that it's probably fine for regular e-mail scenarios, but what about the security over longer time periods (>30 years)? Is the 4096 bit limit for ...
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Is it possible to prove which public key was used to encrypt a message?

Pretty much the title: If Alice sends a message to Bob that she encrypts with Bob's public key, is it possible for Eve to prove that the ciphertext was encrypted with Bob's public key, that the ...