Tagged Questions

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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1answer
86 views

Why is not safe to use the same public key in RSA?

In the RSA context, why is not safe to use the same n (public key)for different people?
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1answer
87 views

All users can write only one can read system

The system I want to implement has the following requirement: All users can insert some sensitive data, but only one, master user, can see it. There is any known, already implemented solution to this ...
0
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1answer
34 views

Shall I set “RSAAuthentication yes” in sshd_config if I use only ECDSA key?

In a context of proprietary client boxes and servers, I want to limit authentication to ECDSA keys. Historically, "RSAAuthentication yes" was used to enable authentication with RSA and maybe DSA keys. ...
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vote
1answer
50 views

Is it safe to use private key encryption for lots of small blocks of data themselves?

I currently handle small JSONs of sensitive information which are guaranteed to be smaller than 100 bytes. You can encrypt up to ~500 bytes with a 4096 RSA key. Is it safe/secure to store these ...
21
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1answer
1k views

What are the odds of an RSA private key collision?

Given the various lengths of RSA key pairs (1024, 2048, 4096) what are the odds of two users having generated the exact same private key?
0
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1answer
51 views

Sharing RSA Public Key for decrypting JWT amongst Load Balanced servers

I'm trying to implement a cookie-less authentication mechanism for a web API that is stateless on the server (does not store session tokens) and can be load balanced across several servers. I have ...
1
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1answer
54 views

Problem with common factor in RSA [duplicate]

In the RSA key generation steps, what if two entities select a common factor to generate n (i.e. p*q1=n1 and p*q2=n2) resulting in gcd(n1,n2) <> 1 ? This will lead to a problem that everyone ...
2
votes
1answer
38 views

How to check a public RSA key file [closed]

Inside a shell script I want verify public RSA file. All I want to do is that find a way to check this file is a genuine public key file, nothing else. Can I ask experts here what are the ways I can ...
0
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2answers
135 views

With RSA, can one ensure that two entities will not have the same private key?

With the RSA encryption algorithm, is there any guarantee that two different entities will not be given the same private keys?
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0answers
87 views

Encrypt in C# program, Decrypt in android application By RSA Keys

I used RSA Encryption for sending message between Server and client. The server program implemented by C# and the Client is an android application. I want to know is it possible a message that ...
4
votes
2answers
118 views

Trying to understand RSA and it's terminology?

I get the gist of RSA but I'm mostly self taught so sometimes the phrases I picked to describe something don't match up with the widely accepted terminology. I'm trying to remedy this. I'm working ...
2
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1answer
124 views

openssl ECDHE-RSA… cipher suite selected while using RSA server cert and ECDSA client cert

The scene: s_server using RSA certificate. s_client using ECC-ECDSA certificate. Client authentication is required (option -Verify set on s_server) Cipher-suite selected after handshake is ...
0
votes
1answer
56 views

GnuPG / OpenPGP: How to eliminate redundancy in PGP private key?

I examined a few randomly generated private keys generated by Gnu PG, and found a lot of redundancy. It is enclosed by -----BEGIN PGP PRIVATE KEY BLOCK----- and -----END PGP PRIVATE KEY BLOCK----- ...
0
votes
1answer
91 views

Key Exchange using RSA

I'm trying to do key exchange using the following scheme. Server generates an RSA-2048 key pair and sends the public part to the client Client generates an RSA-592 key pair (I have to use RSA-592 ...
1
vote
3answers
111 views

Not replacing SSL cert on a rebuilt, formerly rooted Unix Server

If a server was rooted, to the point that we know a Perl script which creates a remote shell was placed on the filesystem remotely, and the server was rebuilt entirely, patching the original Apache ...
0
votes
2answers
97 views

Does public key encryption/decryption speed actually matter?

There have been wars fought over RSA, DSA, and I'm sure other public key encryption algorithms, and usually the arguments are "Algorithm A is faster to encode, but algorithm B is faster to decode". ...
1
vote
1answer
76 views

Are SSH keys and PGP keys the same thing?

I have a 3072 bit RSA key that I generated for use with SSH. Can this key-pair be used with PGP/GPG, or do I need to generate a new pair of keys separately for use in email encryption? Are the two ...
0
votes
1answer
80 views

Securing login form in a desktop app

I currently have a desktop application which requires the user to have a username and a password. These credentials are stored on a webserver (myserver.com), so when he types the username and the ...
1
vote
0answers
66 views

How to generate ECC (160 bits) Keys with OpenSSL? [closed]

I have this problem: I want generate RSA Keys at 1024 bits with OpenSSL. I do this with this commands: For generate RSA Key at 1024 bits: openssl genrsa -out rsa.key 1024 For view the content of ...
1
vote
1answer
68 views

ECDSA/RSA certifcates and cipher selection

In this image can someone tell me if a standard RSA certificate can support the EC*_RSA ciphers listed? If so do you create the typical RSA keys when you are creating the CSR? Also I am fairly ...
1
vote
1answer
52 views

possible to exchange public and private exponent in RSA?

We are implementing https with a third-vendor SSL library in our embedded system. Because of the chosen small public exponent in RSA 2048, encryption is much faster (approx 120ms) than decryption ...
0
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0answers
53 views

Windows User-Level RSA Key Container permissions issue

I have a simple question and I really don't know why it's not working. I've generated new RSA Keyset for user A, grant access for user B and getting error while trying to access that key. Quick ...
-1
votes
1answer
25 views

Choosing right way to secure access to server access via socket

I have an application running on a server, that has an exposed socket to the Internet to communicate with client that is/are application(s) on a phone. How would one go about properly securing the ...
0
votes
1answer
64 views

Can i know how chosen ciphertext attack work on textbook RSA

I am very new to cryptography and I am confused with something? Here is the homework question I am having trouble with: Write a program to attack the Textbook RSA Encryption Scheme, in order to ...
0
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0answers
46 views

Payment Application Integration - Encryption or HMAC

Doing an integration with an online payment provider. Payment provider will be making a web request to my server to provide some information about the basket content. On my end there's no payment ...
-1
votes
2answers
144 views

Why no one makes a message application like whatsapp using RSA keys?

I'm really new and I may sound like a noob so please forgive me. Since gnupg is avaible for android, why does no one makes an app that encrypts every message using a rsa key and just swap the keys ...
0
votes
1answer
226 views

How is the Premaster secret used in TLS generated?

I believe that it uses some combination of the random values sent in the hello messages. From RFC 2246: (TLSv1.0) RSA encrypted premaster secret message Meaning of this message: If RSA is ...
5
votes
2answers
169 views

Security sanity check

A company whose services I'm trying to integrate uses this protocol: An AES key is embedded in an Android library. To authenticate itself, the library sends a SHA1 hash of the key over plain HTTP. ...
0
votes
2answers
126 views

Using given RSA private key without the associated public key

I'm currently following a small game to get more familar with linux and security and got the following task: The password for the next level is stored in /etc/bandit_pass/bandit14 and can only be ...
1
vote
1answer
31 views

What are the security issues of a MITM on an ssh session with rsa keypair

If a user connects to an SSH server using an rsa private key, but does not confirm the server's fingerprint. What kind of information can a man in the middle attack get from the session?
2
votes
1answer
202 views

How does signing work with Elliptic Curve Crypto?

So I have read up and have a decent understanding of how the crypto works with Elliptic Curve Cryptography. I also think I have an understanding of how signing works with things like Elliptic Curve ...
3
votes
2answers
95 views

Isn't this the same as using a certification authority?

Taken from Wikipedia, here is the pretext to my question: A certificate authority (CA) is an organization that stores public keys and their owners and every party in a communication trusts this ...
0
votes
0answers
29 views

RSA, SSLStream - KeyExchange

I'm using sslstream to communicate a client and a server, and i need to use RSA encryption, i have made some tests with a brute keyexchange, using sslStream.write(modulusPublicKey). And receiving like ...
0
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0answers
65 views

Is a android app signing certificate unique?

The Certificates that are used to sign Android applications are generated by the user and not checked or signed by any authority. They are RSA or DSA Certificates and as i read on ...
2
votes
3answers
87 views

Generating deterministic X.509 certificates?

Is there a way to deterministically create an RSA private-key for an X.509 certificate, ideally through a library which has been vetted already? i.e. user enters some phrase like "this is my private ...
0
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2answers
68 views

Why RSA signatures based on the hash of the message? [closed]

Why RSA signatures based on the hash of the message rather than the message itself?
1
vote
1answer
84 views

RSA Signing Key Rotation

I understand the details of RSA encryption/decryption in that a public key can be distributed in the clear since all it can really do anyway is encrypt data. I also understand that this public key can ...
1
vote
2answers
118 views

Expiring AES Key

Is there any way to make an "expiring" AES key? Here's scenario to give a better picture: Say Bob has some data which he would like to share with Alice. Alice has a public and private key, let's say ...
0
votes
1answer
105 views

Encrypting a symmetric key or Small File using TPM and Windows (TBS?)

I'm looking at encrypting a small (500bytes) file using the TPM. This is either doing assymetric encryption with the TPM directly, or using the TPM to store a symmetric key for decryption. This needs ...
0
votes
1answer
73 views

RSA verification time

For a any processor of these or any other processor armeabi (v7-A, Cortex A8); 2012 TI Sitara XAM3359AZCZ100; 1 x 1000MHz armeabi (v7-A, Cortex A9); 2012 VIA WonderMedia 8850; 1 x 1200MHz amd64; ...
1
vote
1answer
198 views

When SSL detect a replay attack?

Suppose an attacker records all messages of a SSL handshake (RSA one-way), and starts a replay attack. When (after which message) can the server possibly detect the attack? Now suppose the attacker ...
1
vote
2answers
113 views

RSA-Based Signature Algorithms

From Beginning Cryptography with Java - chapter 4, digital signatures: Signatures are created using the RSA algorithm by applying the RSA algorithm using the private key and then distributing ...
1
vote
1answer
168 views

Why is it difficult to break RSA?

Given that an attacker only knows the public key and cipher text, why is it difficult to decrpyt the message ? If the knows the N value will he be able to decrypt it ?
3
votes
1answer
81 views

Recommended operational security for generating one's primary key pair?

I have been looking for an operational security guide for generating one's asymmetric key pair for (Open)PGP. I have found plenty of technical guides for how to use GnuPG to generate RSA key-pairs, ...
0
votes
1answer
51 views

Private and public key need to have same algorithm?

The private and the public key from the cert must have the same algorithm, correct? EDIT: Yes of course pub / priv are a key pair. So this code would be legal, to be more flexible (e.g. ECDSA or DSA): ...
0
votes
2answers
87 views

RSA for authentication?

Is it possible to use RSA public and private keys to authenticate two computers (or to make sure they're both the right computers)? If so, how? Thanks!
0
votes
1answer
196 views

Security weaknesses in using RSA encrypted MD5 hash of certificate content

Suppose you have an Internet banking site based on a secure web server running the HTTPS protocol via port 443. The server authenticates itself to clients through an X.509 certificate signed by a ...
0
votes
0answers
357 views

Share and store RSA - public key in java server and vice versa

My requirements are: Requirement 1: Share public key to java server. Steps: Generate public-private keys in iOS app. Store the generated keys in keychain. Send generated public key to java server. ...
3
votes
1answer
160 views

Javascript client side image decryption, does this add any safety or is it flawed

I want to store passport copies safely in a database, the database itself is a normal MySQL database and on a somewhat trusted web server. The user who owns the passport copy should only be able to ...
1
vote
3answers
510 views

Why is RSA decryption slow?

I've been researching the disadvantages of using RSA for encryption, and one I've found repeatedly is that RSA decryption is slow, but I haven't seen an explanation as to why this is. Can anyone ...