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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How ECDHE is signed by RSA in ECDHE_RSA cipher

About ciphers that use ECDHE as Key Exchange and RSA as Authentication: How exactly this two algorithms work together, is ECDHE process encrypted by RSA public key? What are the DH parameters? ...
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RSA public key and private key lengths

I'm having a problem understanding the size of an RSA public key and its private key pair. I saw different key sizes for RSA algorithm (512, 1024,... for example), but is this the length of public ...
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Secret, Public, and Private Keys?

...and nonces. Can someone show an example of how this actually works using small intelligible numbers? For example: secret key: "100" public key: "10" private key: "1000" I am just trying to ...
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489 views

What is the role of RSA in ECDHE-RSA? [duplicate]

I have read some textbooks and not found a convincing explanation. In the cipher suite ECDHE-RSA-AES128-GCM-SHA256, what is the role of RSA in the first part (ECDHE-RSA)? This part of the cipher ...
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46 views

SSH Key: Ed25519 vs RSA

A lot of people recommend using Ed25519 instead of RSA keys for SSH. The introduction page of Ed25519 (http://ed25519.cr.yp.to/) says: [..] breaking it has similar difficulty to breaking [..] RSA ...
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Why did browsers deprecate 1024-bit RSA, but retain SHA-1?

I was reading Mozilla's security blog Phasing out Certificates with 1024-bit RSA Keys. Effectively, some browsers are deprecating 1024-bit RSA for CAs and Subordinate CAs because the certificate must ...
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41 views

Who uses 1024-bit RSA?

I know they're deprecated, but does anyone still use 1024 bit RSA encryption or certificates? Do you know of any examples of systems that use it today? What would be the implication if someone ...
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1answer
71 views

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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54 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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53 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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51 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 ...
3
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70 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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70 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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3answers
136 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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1answer
33 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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136 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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41 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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102 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
89 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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3answers
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
33 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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64 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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193 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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173 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 ...
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1answer
88 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 ...
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1answer
128 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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52 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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46 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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227 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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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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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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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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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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1answer
69 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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41 views

public key formats [closed]

I have the following PEM format public key: -----BEGIN PUBLIC KEY----- MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDguwHaldTclMAFg1BQ45Q8DPIc ...
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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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126 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 ...
3
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1answer
162 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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2answers
100 views

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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101 views

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 ...
2
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2answers
121 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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156 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, ...
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853 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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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
73 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 ...