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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Signature scheme using RSA and SHA512

What do you think about this signature scheme using RSA with 4096 bit keys? Being R pseudorandom padding, fixed length (4096 - 512 bits): RSApriv(R || SHA512(M)) I know that it's not as secure as ...
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What is Provable Security? [closed]

In computer security, what does provable security mean? I read the Provable Security article on Wikipedia, and I was able to grasp the basics. I would like to see this described in more detail, using, ...
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Obtain X.509 Certificate Fingerprint from Certificate Info

I would like to obtain the SHA1/MD5 fingerprint of an X.509 certificate in order to compare it with the one presented by a server before connecting. However, I currently don't have access to the ...
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Why does an RSA key (256 bits) have more than 256 bits of ascii characters?

As an example, I generated a 256 bit key pair. The private key (when saved to a file by puttygen) is: AAAAIGZcM73lV3Uk/psErZAYA0F+4xK78FtFoVi2fdypv92tAAAAEQDdOhyFJ6iV ...
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55 views

SSL over self-implemantation of RSA?

I currently write a client application which communicates with a PHP server. The application itself requires valid user credentials and get all of his information by doing POST requests to the PHP ...
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103 views

Soft tokens - multiple profiles on same smartphone

Some of our clients have started migrating to soft tokens instead of hardware ones for two-factor authentication to their network. We have apps like RSA SecurID and VIP Access on our smartphones. The ...
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84 views

Why not just pad RSA with random bytes

So, i understand that we should always use padding on RSA so that if we send the same message with different keys, the Chinese Remainder theorem can not be used to decrypt it. When looking at the ...
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2answers
179 views

Encrypting USB traffic: Is RSA necessary for AES session key exchange when using pre-installed secret keys?

I need a solution to encrypt USB communication between device A and device B. I was thinking about configuring each device with a secret RSA-2048 key, which would be used to exchange an AES-256 ...
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290 views

Is an >=2048bit key with Asymmetric encryption secure enough to negotiate a Symmetric encryption key?

Let's say that a client app already knows the public key of the server to which it needs to communicate with and the client app needs to connect to the server using a normal non-secured internet ...
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1answer
210 views

Why should I use easy-rsa when using OpenVPN?

Reading this guide on how to setup an OpenVPN server on a Raspberry Pi, I saw this line: 4) You don’t want anyone who finds your VPN server address to be able to connect. So next, we’re going to ...
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154 views

How do openvpn/easy-rsa generated keys map to RSA algorithm variables?

I was reading up a little on openvpn and pki infra and am confused by some of the questions posed by my colleague. :) This answer did help me understand more: ...
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1answer
143 views

Key generation: Differences between GnuPG classic, stable, modern?

I plan to create a 4096 bit RSA&RSA key pair: gpg --gen-key --personal-digest-preferences SHA512 --cert-digest-algo SHA512 Is there any difference in generated key quality between versions 1.4 ...
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1answer
228 views

Use openssl key to decrypt file in android/java [closed]

I want to decrypt file encrypted in openssl in java. File is encrypted with private key using openssl and on java side i want to decrypt it using public key. The code: public void testRSA() throws ...
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1answer
90 views

PKCS12 - private key protection

I know that PKCS12 private key is protected by a password, but what is actually done with the password ? Does it use PBKDF to derive the key from password ? That would be a problem as if you change ...
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1answer
1k views

How does SSH use both RSA and Diffie-Hellman?

SSH protocol 2 allows you to use DSA, ECDSA, ED25519 and RSA keys when establishing a secure connection to a server. (Keep in mind for this question that I'm only familiar with the procedure and ...
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1answer
290 views

How encryption/decryption of RSA private key by passphrase works?

I would like to know how exactly the encryption of private key by passphrase works. I am a software developer with no background in cryptography and I know only some basics. When I open the private ...
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3answers
793 views

How do RSA SecureID ® Keys Work?

I have been using RSA SecureID ® Keys for quite some time now (perhaps 10 years), for things such as securely my home banking account online or accessing my company's network of computers from home. ...
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Use of RSA in Yaksha Security System

So I'm reading over the Yaksha Security System and see it is based on the RSA cryptosystem and a centralized server, easy enough. What I'm slightly confused on is the math behind the related keys. It ...
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1answer
88 views

Calculating D-Wave's integer factorization capabilties

D-Wave has teased the ability to perform integer factorization previously, but if you jump to ~10:00 in this presentation they actually appear to outline how they can perform integer factorization ...
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Does it matter which key is considered private and which public?

Mathematically, is there a difference which set of characters is private_key and which one is public_key? @Edit At the moment of asking I was thinking on RSA, not asymmetric crypto in general.
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4answers
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How is security of server's RSA private key is ensured?

We repeatedly hear news of hacking of passwords from PW database (server side) but nothing about hacking of server's RSA private key (not asking regarding finding p and q for a given public modulus ...
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1answer
107 views

Use of safe prime in RSA digital signature scheme

For the RSA digital signature scheme , Alice has a pair of public and private keys as denoted by Public key : (e,n) Private key : (d,n) Assuming Alice wants to send a message M to Bob , she would ...
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367 views

Sign SSL certificate with root certificate using openssl

I have created a root certificate, My Root Certificate, with a private key, RSA Private Key 1, using the openssl terminal command. I would like to make a certificate chain such as the following: My ...
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1answer
67 views

What are the compatibility implications of generating a new TLS key?

The guide I'm following says to use openssl genrsa to generate a TLS key, which I did. I've changed the CSR generation command to use SHA256 instead of SHA1, but I'm still not sure if this is the ...
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178 views

What is the impact of RSA key's size on CPU load?

I use ssh connection encrypted and compressed. If I use small RSA keys or very big RSA keys, what is impact on CPU load for compression, for decompression and on bandwidth (encrypted file size) ?
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New PGP key: RSA/RSA or DSA/Elgamal?

I wanted to create a new PGP key using GPG Keychain Access on my Mac. One of the options was to choose keytype: RSA and RSA DSA and Elgamal RSA (Sign only) DSA (Sign only) I found this Superuser ...
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141 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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125 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 ...
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1k 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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1answer
87 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 ...
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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?
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488 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 ...
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96 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 ...
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1answer
577 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 ...
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158 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
188 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 ...
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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 ...
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1answer
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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 ...
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1answer
275 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----- ...
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140 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 ...
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120 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 ...
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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". ...
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1answer
346 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 ...
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1answer
130 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 ...
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107 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 ...
2
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1answer
189 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 ...
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86 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 ...
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134 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 ...
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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 ...
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1answer
150 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 ...