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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Managing keys generated with insufficient entropy

Since the Linux RNG which provides /dev/random (and by extension /dev/urandom) is seeded by "mouse and keyboard activity, disk I/O operations, and specific interrupts" (source, PDF) and since virtual ...
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49 views

Choose your own exponents in RSA?

In another interesting post, one of the developers/security researchers behind Phuctor suggests that using different exponents with RSA keys will "[increase] the costs of attacking your setup ...
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49 views

Offline RSA strong prime test similar to Phuctor?

One of the ways that RSA keys get consistently owned is when they're generated without enough entropy. Dan Kaminsky refers to a study which found that 1 in 200 RSA keys were badly generated and these ...
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41 views

Prevent padding oracle attack on key exchange process

I found in my searches that the padding oracle attack can be used against the RSA with PKCS1PAdding or OAEP padding, and I used this algorithm for a symmetric key exchange. How can I prevent a padding ...
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67 views

toy OpenPGP encryption with manually generated keys

I've been playing around with OpenPGP encryption for a little while. Here are the steps I've followed: Generate an unencrypted public/private key pair in my keyring with gpg --gen-key. Dump the ...
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48 views

RSA: same symbols in plaintext give same symbols ciphertext?

I just started studying Information Security, but I just ran this program: http://www.sanfoundry.com/cpp-program-implement-rsa-algorithm/ and faced this strange thing. For small keys (don't try to ...
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66 views

What is encryption by RSA with AES? [duplicate]

By visiting some websites, like bank websites, we can see for example: TLS_DHE_RSA_WITH_AES_128_CBS_SHA, 128 bits, TLS 1.0 I would like to know: What does mean CBC? TLS 1.0 is an old version, is ...
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130 views

Secure Hash of a very short payload - is it possible?

I am looking to verify the integrity of a very small payload, approx 64 bytes, which will be stored in a QR code. I need to verify that the payload has not been generated or altered by an attacker. ...
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32 views

Determine private key size using public certificate [duplicate]

I have a public certificate in a PEM (.pem) file -----BEGIN CERTIFICATE----- MIICsjCCAZqgAwIBAgIJAMA1YIQ2JLXDMA0GCSqGSIb3DQEBBQUAMBExDzANBgNV ... 29V/R9RZOoSBHDzGPL84wm4qojMuwQ== ...
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1answer
126 views

How many qubits are needed to factor 2048-bit RSA keys on a quantum computer?

I've been reading about quantum computing and turns out that 512-bit quantum processors are already a thing. I also read about Shor's algorithm, which can break RSA and several asymmetric encryption ...
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40 views

RSA vs DSA Digital Signature Message Digest Recovery

I'm learning about signatures using RSA and DSA, I've come across this little fact: RSA can recover the message digest from the signature, whereas in DSA this isn’t possible – you have to have the ...
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101 views

someone may be doing something nasty

I have an ssh server. earlier toady, I was about to login to my server, when I got a message that said something along the lines of "Someone may be trying to do something nasty" and indicating a man ...
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1answer
86 views

How does this encrypted webmails works?

In the last days I was looking on Tutanota, ProtonMail, LavaBoom, and others webmails that promise to respect users privacy. For all those, the one I most liked was Tutanota. I did few tests with ...
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168 views

If TLS 1.2 is considered unbreakable, why do the NSA and other agencies invest in supercomputers? [closed]

If a 2048-bit RSA key and a 256-bit AES key are considered to be unbreakable within the foreseeable future by any kind of computer, why do the NSA and other intelligence agencies invest in ...
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0answers
29 views

How to use IIS ssl certificate(CNG) for data encryption

I want to use RSA to encrypt/decrypt some data using IIS's ssl ceritifcate, from within a web service(WCF). I've managed so far to do this by using .NET security ...
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69 views

RSA private/public keys

Is it possible to recover a private key, given a public key and a substring/a part of the corresponding private key?
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61 views

RSA vs DSA working methodolgy?

I have looked for various answers but I am being confused on how does RSA can be used for both Digital Signatures and Encryption/Decryption like in "TLS_DHE_RSA_..." or "TLS_RSA_.." cipher suite ...
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22 views

SSL Handshakes and authentication? [duplicate]

I was just wondering if someone could explain the complete process of SSL handshake with certificates, public - private keys and MAC exchange. And in which cases does the Certificate warnings arise ...
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1answer
173 views

RSA key sizes v/s public key sizes

I am new to cryptography. I have an api provided by a bank. The banks says that they are using RSA algorithm with 2048 bits. We used this api first to get the public key. Here is the sample public ...
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3answers
154 views

Looking for a (simple) utility to decrypt rsa-encrypted text in Windows?

Quick question: I'm looking for a simple utility program to be able to decrypt rsa-encrypted data (either base64-encoded or binary attachment) on a Windows workstation. Scenario: There is a group of ...
3
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1answer
86 views

How is JWT implemented?

I'm using django-rest-framework-jwt in one of my APIs. As you might know, the concept is simple: you send username and password and you get a token back. The token is not stored anywhere on the ...
3
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1answer
122 views

Asymmetric / end to end encryption for web messaging app

Background I'm trying to design a secure and sustainable web app for messaging. The purpose is to learn how to create secure web application. The application is suppose to be written in Javascript ...
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50 views

How to import key BLOB generated from Microsoft CryptExportKey from Linux

I have a private/public key pair saved as key BLOBs which were in fact exported with the Microsoft "CryptExportKey" API. Now I need to use the same key pair (specially the public key) under Linux ...
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45 views

Private messages for an ios app - how secure is this system?

I'm designing architecture for sending private messages (i.e. only sender and receiver are able to read a message). Client side - iOS, server side - Parse.com I'm thinking of using RSA to ...
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2answers
214 views

Converting ECC Private key to PKCS#1 format

Is there any way to convert an ECC private key to RSA PKCS#1 format? I have tried converting it to PKCS#8 first using OpenSSL: openssl pkcs8 -topk8 -nocrypt -in EC_key.pem -out pkcs8_key.pem This ...
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104 views

Is it possible to wrap and export RSA private key in FIPS 140-2 Level 3 compliant hardware?

I would like to do the following on FIPS 140-3 Level 3 certified cryptographic token using PKCS#11: Generate RSA key pair on token Import AES key from multiple components Wrap and export RSA private ...
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44 views

PCI compliant RSA key generation and getting value of private exponent

Is it possible to generate RSA key and get its private exponent in clear and to be compliant with the following PCI requirement?: Keys must be generated so that it is not feasible to determine that ...
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Safenet iKey 4000 RSA key pair generation in FIPS 140-2 compliant mode

I need to generate RSA key pair and show the public and private key on screen (in a secured room). The algorithm must be FIPS approved. So I would like to use iKey 4000 which is FIPS 140-2 level 3 ...
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73 views

Best practices for Private Key management

How should I go about handling my RSA Private Key for my high-security Rails web application? This may seem like a "soft" question, not related to cryptography per-se, but is nevertheless very ...
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73 views

How strong is the performance impact of signing when using RSA_AES_256_ECDH

To encrypt web communication, I use SSL with a RSA key with a length of 2048 bit, AES key's with a length of 256 bit and the ECDH-algorithm for the negotiation of the AES key's (or to exchange the ...
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64 views

Same RSA key pair for all users

Let's say in my computer running Debian i have an RSA key pair generated by user foo and copied the public key to server_A for allowing key based authentication in ssh for foo. Now my question is can ...
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1answer
41 views

public key formats [closed]

I have the following PEM format public key: -----BEGIN PUBLIC KEY----- MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDguwHaldTclMAFg1BQ45Q8DPIc ...
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65 views

Decrypting old data from PHP extension

I recently came across an old website of mine that I had used the PageProtectionPlus MediaWiki extension to encrypt parts of. I'm curious to see what I wrote, but the extension is no longer supported ...
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116 views

Encrypting short data with RSA only?

I have a case where I need to create recovery accounts and I want to create them so that nobody knows the password to them until/unless necessary. Hence, I thought that I would do it using RSA - when ...
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125 views

Why use anything other than RSA for transmission encryption?

Being fairly new to the cryptography and data security space, I have sampled a few "Introduction to cryptography" sites/textbooks and they all seem to start in the same general way: This is a Caesar ...
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159 views

SSH raspberry pi security

I've setup an SSH server on my Raspberry Pi. I use RSA keys to login, I disabled root login, password authentication and I use port forwarding to login from outside my network. I can see the ...
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How can I create my own public certificate using openssl?

I have a public key/private key pair i generated using two primes p and q. I now need to use openssl to sign and create the certificate. I heard req utility and wrote this from the man pages. openssl ...
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What type of encoding do .pem files use to store the key?

What encoding is the modulus in RSA cryptography stored as in a .pem file? Is it something similar to base64 of the modulus? I can retrieve the modulus using the following: openssl rsa -in ...
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2answers
116 views

RSA and AES combination in offline situation

I need to securely request and receive data from a server. The client has the RSA public key, and the server has the RSA private key. So I am generating a random key for AES-128/CBC cipher and ...
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144 views

openSSL selects ECDH-RSA instead of ECDH-ECDSA

I am trying to do a secure connection with openSSL between a client and a server that I wrote. When I try to select the cipher suite to use, I do SSL_CTX_set_cipher_list(ctx, ...
12
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841 views

Relationship between RSA, Diffie-Hellman Key Exchange, PKI and X.509?

I am getting confused with RSA, Diffie-Hellman Key Exchange, PKI and X.509v3. I took a look of RSA's mathematics algorithm, it seems like a encryption algorithm, right? Generating public key and ...
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476 views

Strength and length of Symmetric vs Asymmetric keys [duplicate]

There are many questions surrounding the differences between symmetric and asymmetric encryption keys. I think I've read them all at this point. But I'm still left wondering: Why does a "secure" ...
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1answer
70 views

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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3answers
900 views

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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1answer
45 views

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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1answer
55 views

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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98 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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1answer
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
176 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 ...