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.

learn more… | top users | synonyms

3
votes
2answers
100 views

How to counter the security risks of shared prime factors among RSA moduli employed in practice?

A. K. Lenstra et al. in an extensive examination of the RSA moduli employed in practice (http://infoscience.epfl.ch/record/174943/files/eprint.pdf, p.10) wrote that they "could not explain the ...
2
votes
1answer
82 views

Licensing system for client side code web application

I have a client-side web application running on SharePoint Site Collection, each site collection has it's own unique id. I want to use a licensing process to lock the app to a site collection. This ...
4
votes
3answers
188 views

Strange RSA usage - how secure is it?

Is following communication scheme secure? To my mind, it uses RSA modulus and public key exponent as a cryptographic secret, which is strange usage of RSA, but can it be easily broken because of ...
1
vote
0answers
27 views

Can there be two certificates with a same serial number in the world? [duplicate]

Recently I came across this odd question. I hope, Serial number is unique across certificates signed by a particular CA. So is there any chance that two different CAs sign two different certificates ...
4
votes
2answers
171 views

Passwordless website authentication scheme

I have a userbase which really isn't all that inclined to create a secure password for a website. They're also almost entirely on mobile devices, so I would like to try something a little different ...
1
vote
0answers
99 views

CMS signed data OpenSSL verification error

I have a CMS signed data that is successfully verified through Java BouncyCastle library. When trying to verify through OpenSSL, I am getting the following error: >openssl smime -verify -inform ...
2
votes
0answers
56 views

Why is DSA is faster than RSA for signature generation but slower for validation?

Almost on every post comparing DSA and RSA, I see a point brought up: DSA is faster for signature generation, but slower for validation. I wonder why this is? For example, in DSA, to sign something, ...
-1
votes
1answer
92 views

How to use RSA private key for TripleDES encryption?

Our goal is to send SOAP messages to a web service, signing these messages using TripleDesRSA15 algorithm. Web service staff sent us a .pfx file, where certificate for encryption is stored. I'm able ...
3
votes
2answers
128 views

Encryption in peer to peer chat

For a homework assignment I'm developing a chat service that will be able to communicate within a single network. The communication channel should be encrypted with RSA. Should I generate keypairs ...
0
votes
1answer
96 views

Questions on the variations of RSA keys

I've built a simple application that reads in an RSA key, checks the header and starts identifying properties of the RSA key to make sure it is valid (Using child_process in express to run $ ...
2
votes
2answers
85 views

Is this a secure Digital Signature + Encryption method?

I am trying to wrap my head around Digital Signatures and how RSA Encryption supports them. And which order to do them along with what specifically to encrypt. So say we have Alice and Bob and a ...
0
votes
0answers
40 views

On the Import Client Key screen in Bitvise what is numeric field just next to the Location Profile dropdown?

What is this field for? I know I saved a profile in the beginning, and I want this private key to be attached to just the profile that I'm using, but what on earth is that numeric field for?
1
vote
1answer
39 views

Is D parameter of the RSA strong enough to be used as secret for HMAC calculation?

Short question: Is the D parameter of the RSA alghorithm crypthographically strong enough to be used as a secret key for generating SHA-256 hash value? Long question: I'm working on windows platform. ...
0
votes
1answer
59 views

What effect would removal of RSA tokens from mobile phone have on surveillance? [closed]

Reading the comments at Bruce Schneier's blog, I came across this recommendation by someone where they write: @Michael_H - Here you go, buy yourself a cheap Huawei G6620 on eBay, any network, ...
1
vote
0answers
33 views

Storing user private key paraphrase during session

We have a web application which is used to store secrets (passwords, pins etc) and share them to other system users. Currently for encryption we use AES with single encryption key, and all secrets ...
1
vote
2answers
90 views

secret key not available for decryption, but still shows up in GUI

I'm trying to decrypt a message using my personal secret key. When I try to decrypt the message (using gpg --decrypt message.txt), I get the following error: gpg: encrypted with RSA key, ID 3810D17A ...
42
votes
4answers
5k views

Why is key exchange necessary at all?

Let's say "Alice" and "Bob" want to communicate with each other over an insecure network. Using Diffie–Hellman key exchange, they can get the same symmetric key at last. However, as I understand, ...
1
vote
3answers
276 views

Using a stolen certificate on a server

Yesterday I asked the following question regarding what would happen if you placed a stolen certificate on your own server and edited the 'host' file so that the DNS name matched: Could a stolen ...
1
vote
2answers
56 views

RSA and Psuedorandom Number Generator

I want to give a presentation on school about RSA encryption and decryption. I understand the basic of calculating a public and private key with two small prime numbers. And how to use those keys to ...
0
votes
2answers
123 views

RSA: Do private keys have to be private?

I was thinking about using RSA, but in reverse. Where everyone has the private key, and only the server has the public key, so that all the clients can decrypt a message from the server, and the only ...
1
vote
0answers
55 views

How to decrypt RSA cipher text? [closed]

How can I decrypt an RSA cipher text in which I am only provided with a public key and the cipher text. The person who encrypted it made a mistake in taking the exponent.
4
votes
1answer
107 views

RSA fingerprint automatic change or have I been hacked?

today I tried to connect to my Digital Ocean VPS through Putty(kitty) as usual, but I got the message that the server's cached fingerprint had changed, and that it could be a security compromise. I ...
3
votes
0answers
55 views

Could RSA be used as a block cipher?

I always thought that the reason we couldn't use it was because it required too many CPU cycle. But an answer from @TomLeek indicated that this was not the case : ...
0
votes
1answer
114 views

Generate RSA2 key in OpenSSH format in windows

I have to generate a key, RSA v2 in OpenSSH format. I am a bit confused. I am trying to generate it using Putty key generator. There I see an option SSH2-RSA and SSH1-RSA. So is SSH2-RSA the RSA2 key ...
2
votes
2answers
100 views

Is it possible to protect a DER private key with a password?

I want to write an API, based on OpenSSL, that can convert an RSA private key stored as DER to the PEM format. I'm just wondering if a DER key can be password-protected. I've searched the OpenSSL ...
3
votes
1answer
273 views

How can I use my HSM to turn a CSR into a certificate?

I create a CSR using OpenSSL, so I have public and private keys. Now I want to sign this CSR and convert it into an X.509 certificate. The only problem is, my signer is a custom HSM. I can send bytes ...
3
votes
1answer
76 views

Public-key encryption for pre-shared keys with MAC

What well-known algorithms are suited for the following task? I need system A (and only system A) to be able to encrypt some data, with system B being able to decrypt it. At system B, I want to be ...
1
vote
1answer
69 views

Need asymmetric encryption(not signing) where server encrypts and client decrypts

So I'm trying to build a licensing server, where the licenses of the applications need to be checked when logging in or when the application gets used. But some of those application work offline most ...
0
votes
1answer
26 views

Publish an image to github with rsa keypairs, what are the security risks? (NOT PRODUCTION)

I have Dockerfile for an image that I would like to publish to docker hub so it can be easily available to users without building the image themselves. The whole thing is meant for labbing and ...
5
votes
1answer
528 views

GPG (PGP) decryption speed issue

We are new to using GPG and we have a very strange issue with decryption speed when using RSA keypairs, which are generated by using different tools (GPG for Windows, DidiSoft OpenPGP Library for .NET ...
2
votes
1answer
197 views

How do I find a PKI smart card reader/writer for development (Microsoft .NET)

I would like to learn how to develop software leveraging PKI smart cards. Ideally, I would use Microsoft Base Smart Card CSP, but I really just need the ability to store symmetric and asymmetric keys ...
16
votes
2answers
2k views

Is it bad that my ed25519 key is so short compared to a RSA key?

I recently generated a new SSH key in the ed25519 format. The public key is only 69 bytes long while my old RSA key is 373 bytes. From my perception ed25519 is the more recent and secure format. So ...
0
votes
1answer
141 views

Encryption and Signature with same RSA private key

Talking about cipher-suites that use RSA both for sign of DH parameters and for digital signature. The keys used for these process are the same, or is there a public and private key for each one? If ...
2
votes
3answers
199 views

How to deliver an encrypted message to multiple recipients without revealing keys

Let's say I have generated a private and a public key. I create a message and encrypt it with the public key. I deliver this encrypted message and a private key to multiple recipients. Why would I do ...
1
vote
1answer
73 views

RSA signature on TLS

In a TLS handshake using ECDHE-RSA, the ServerKeyExchange frame must include the ECDHE ServerPublicKey, signed with its RSA private key, as specified in the RFC 4492. Got it. Trying to implement an ...
5
votes
3answers
535 views

Is it safe to use same key pair to encrypt and sign? [duplicate]

Would it be easier to hack a private key by having multiple encrypted and/or signed messages from the same person than having only encrypted or only signed messages? Should I use one private key to ...
1
vote
2answers
94 views

Public Key Pinning and subdomains

Shortly I have intend to install new webserver and I'd like to secure users a little bit more. I already have domain, (virtual) server and everything else that matters when configuring a server. ...
0
votes
0answers
192 views

DSA, ECDSA and RSA [duplicate]

Conventional wisdom these days is that in the context of SSH keys, DSA is insecure and RSA is preferred (or that they are both fine, but RSA is more secure, depending on who you ask). As I understand ...
0
votes
1answer
388 views

breaking down RSA/ECB/OAEPWITHSHA-256ANDMGF1PADDING

So Java has a mode called RSA/ECB/OAEPWITHSHA-256ANDMGF1PADDING. What does that even mean? RFC3447, Public-Key Cryptography Standards (PKCS) #1: RSA Cryptography Specifications Version 2.1, section ...
1
vote
2answers
183 views

Significance of the difference between DSA and RSA in signature verifying speed

I have run openssl speed and the output on my CPU for longest available DSA key size, which is 2048 bits: sign verify sign/s verify/s rsa 2048 bits 0.029185s ...
0
votes
2answers
382 views

Diffie-Hellman and MIM attack, and server identity

Diffie-Hellman and MIM attack: When variants of Diffie-Hellman algorithms like DHE, ECDHE etc. are used in SSL handshake for key exchange then can it become prone to man in middle (MIM) attack. ...
1
vote
0answers
339 views

How to unwrap exported key from safenet HSM? [closed]

I am trying to write a software that will inject keys generated inside an HSM into a POS device, in the same way as described here I'm using the Safenet emulator(software-mode) + the wrap/unwrap ...
5
votes
1answer
267 views

Using ECC for PGP-Master Key in combination with Yubikey

I acquired a Yubikey Neo last month. Now I want to use the Smart-Card functionality for PGP. I followed the official guides on the Yubico Website tested it with 2048 RSA Keys and it worked fine. But ...
6
votes
2answers
193 views

Is RSA useless when my app is fully decompiled?

I've programmed an Android game with Unity Engine. As you know in Unity, scripts compiled into one file named "Assembly-CSharp.dll". I wrote my scripts in C#. After I compiled whole game into .apk, I ...
2
votes
1answer
201 views

GnuPG - Problems with large RSA keys

I have read that GnuPG limits the size of RSA keys to 4096-bits because this could lead to problems with running out of secure memory. But in which operation is this the case? Generating the keys? ...
0
votes
1answer
102 views

SSL key decryption [duplicate]

I am wondering if I can get the SSL Key given the following conditions: Encrypted Text is known Decrypted Text is known Any ideas on how I can create a program that does this?
3
votes
2answers
217 views

ECC and RSA 10K stronger claim

There are a lot of websites where it is claimed something akin to this but no explanation on the basis. "ECC key size of 256 bits is equivalent to a 3072-bit RSA key and 10,000 times stronger than a ...
2
votes
1answer
227 views

Use RSA Encryption With ASP.NET

My goal is to implement asymmetric encryption in an ASP.NET website to secure user-entered Social Security Numbers. I want to encrypt the SSNs with a public key, and only display a masked version, to ...
2
votes
1answer
451 views

Using RSA for Web Application Authentication

I have a network that is only accessible through bastion servers over ssh. In it, I am developing web applications that are exposed to end users via GUI's served up over websockets. All traffic into ...
3
votes
1answer
158 views

How bad an idea is intentionally using short RSA keys for signing CloudFront private-content URLs?

While pondering a question on SO about efficiently generating signed private-content URLs for CloudFront I decided to check what sorts of savings could be found by using a shorter RSA key. With the ...