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Questions tagged [openssl]

OpenSSL is an open source implementation of the SSL and TLS protocols. Questions about how to use the OpenSSL tools and libraries are usually better asked at Stack Overflow or Super User.

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59 views

AES 256 CBC - Storing local data, how to save IV vector?

I want to use AES256 CBC for protecting small data (<100kb) against misusage for my application in the local store folder. I'm not an expert at data encrypting so I'm to try to understand it step ...
5
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1answer
322 views

Which elements of private RSA file are really constitutive of private key?

I have used openssl rsa to generate a RSA key of 2048 bits and as expected output belongs to a file beginning with ...
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1answer
45 views

No way to do ECDH with OpenSSL from the command line?

I've scoured this website and the OpenSSL wiki pages, and done numerous internet searches, and I've come to the seemingly incredible conclusion that one cannot generate an ECDH shared secret key using ...
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0answers
6 views

OAEP padding for OpenSSL [migrated]

I'm trying to decrypt a file using a private RSA key using OpenSSL. It keeps giving me the same 3 errors that I believe can be solved by adding oaep padding to it. What is the syntax for adding the ...
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0answers
4 views

How are sessions handled in case of long lasting communications? [migrated]

How does TLS 1.3 handle communication between the server and the client where it can last for a very long time (like years), without any pause in it? My concern is that the longer a key is used the ...
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1answer
34 views

Create self signed certificate from modulus, private and public exponents of RSA

I have the values of RSA public exponent $e$, the secret exponent $d$ and the modulus $n$. How can I create (for example using openssl) a self-signed certificate using the RSA key $(n,d), (n,e)$? Is ...
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0answers
11 views

OpenSSL performance test on a specific file [migrated]

I m new in this world of Cryptography. I`m trying to check the performance of the various algorithms on with OpenSSL. Looking on the internet I find this command : openssl speed aes-128-cbc des ...
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2answers
39 views

CSR creation in android

I'm trying to generate a csr with spongyCastle in android that has to be submited to a webservice. My problem is that the webservice always complains that the CSR is not in DER or PEM format. On the ...
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1answer
76 views

How are AEAD, GCM, CBC, Poly1305, EtM, MtE and E&M related?

I am using OpenSSL 1.1.1 to implement a TLS 1.3 communication module so I tried to learn how data integrity and authentication is ensured. I read a lot about AEAD, GCM, CBC, Poly1305, EtM, MtE and E&...
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2answers
52 views

A simple misunderstanding of SSL/TLS

I just came to learn about Deffie Hellman Key Exchange. And a little bit about RSA. I came to DH from something about SSL. From what I understood before is that SSL uses DH and TLS uses RSA, but after ...
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15 views

Are there any specific weakness in this crypto implementation?

I am reverse engineering the firmware of a particular router/modem. I am focusing on the functionality to export the router configuration. I an searching for a way to decrypt the configuration backup ...
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0answers
41 views

SDES algorithm purpose

What is the purpose of SDES algorithm? (Session Description Protocol Security Descriptions) What are the problems in the way it exchanges keys? I have tried to search about these quastions but i ...
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1answer
64 views

CSR signature using elliptic curve [closed]

We've been asked to generate a certificate signing request using elliptic curve and we can't use any third-party library as it's an embedded application with very limited resources). We are used to ...
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2answers
127 views

Using RSA encryption with OpenSSL library: secure?

I'm working on a small program (in C) that writes encrypted log files, but there are a lot of articles out there that say you should avoid RSA whenever possible. However, most of these articles also ...
3
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0answers
45 views

Does Openssl 1.1.1 library supports sending multiple identities as part of PSK?

Does Openssl 1.1.1 supports sending multiple ticket identities as part of PSK? i have gone through the openssl code and i don't see that openssl supports it. could someone please confirm it if i ...
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1answer
486 views

curve25519 by openSSL

How can i generate ec curve25519 keys using openSSL? When I run openssl ecparam -name curve25519 -genkey -noout -out private.ec.key I have this message ...
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1answer
42 views

How to use openssl securely? [closed]

I don't want openssl to log my keys and passwords... but I don't use gpg as I need more manual control for my purpose. I also don't like gpg and would like to use openssl without logging. Does ...
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1answer
152 views

Naming convention for NIST elliptic curves in OPENSSL

NIST standardized 5 elliptic curves (P-192, P-224, P-256, P-384, P-521) for prime fields. When I looked into openssl, these curves are named as prime192v1, secp224r1, prime256v1, secp384r1, secp521r1. ...
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1answer
69 views

Encrypt multiple RSA keys with same passphrase

I have to create and store a bunch of RSA key pairs with openssl. The private keys will be encrypted with the aes256 option and a very long, random password. Would it be safe to use the same password ...
5
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3answers
1k views

Why does OpenSSL differentiate between PSS and non-PSS for private key generation?

RSA-PSS private keys The following command will generate an RSA-PSS private key: ...
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1answer
276 views

Is the KDF pbkdf2 included in the openssl suite? [closed]

I'm trying to encrypt a file using DES in CBC mode but when I try to specify the key derivation function it tells me my command is wrong. It only fails when I try specify the KDF and works when I don'...
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1answer
2k views

Is openssl rand command cryptographically secure?

I'm wondering if the openssl rand command produces cryptographically secure random bytes. For example when in need for a random password or token: ...
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1answer
175 views

When do clients use TLS in PSK mode?

The TLS protocol can perform the handshake in different modes. Either fresh handshake where new keys are generated, or using Pre Shared Keys (PSK) or what was know as Session Resumption in previous ...
2
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1answer
520 views

Length of password requirement using openssl aes-256-cbc

I am using the following OpenSSL command to AES 256 encrypt a file: ...
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2answers
390 views

Using Diffie-Hellman secret key to encrypt/decrypt data?

My end goal is to encrypt data with AES-128, send it to other process and decrypt it there. While using DH key exchange protocol. I have used DH to generate a 256 bytes shared secret, but I can't use ...
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2answers
356 views

Why does Laravel only support AES-256-CBC?

Modern Laravel uses OpenSSL to provide AES-256-CBC encryption along with a MAC. However, I was under the impression that this is not a particularly secure approach. Why does Laravel only support AES-...
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1answer
119 views

How to determine the fastest OpenSSL cryptographic algorithm

This question does have to do with cryptography, but not necessarily with encrypting meaningful data. This is my first post here, so if I'm going about this question incorrectly please let me know. ...
2
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1answer
796 views

How does openssl signature verification work?

I would like to know how openssl verifies a digital signature? I know that it uses this command to verify a signature: ...
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1answer
228 views

Does RSASSAPSS use RSA signature

I just need to know is it correct to classify the RSASSAPSS scheme and sha[256 | 512 | 1]WithRSAEncryption all under RSA ...
1
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1answer
126 views

openSSL and ECDSA key format inspection

If I run openssl ec on a key that I have generated with openssl ecparam -genkey I get one extra prefixing 0x00 in the private ...
3
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1answer
534 views

SSL - encrypt with private key and then with public key?

Say there are 2 sides that wish to communicate: side A and side B. Let's say we are looking at side ...
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1answer
194 views

How to check a signed CSR with openssl?

I just learned that a CSR can be signed. See this Why is a CSR signed and which key is used for signing? I tried to check the csr with below openssl command, but failed with errors "139942025398160:...
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1answer
68 views

Unable to reproduce correct signature data

"Skatteetaten" is the Norwegian tax authority. We're currently trying to implement signing of messages for digital cash registry systems and i'm not able to reproduce the desired signed data. Went ...
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1answer
39 views

When a program using openssl library is using a certificate, does the server check if the issuer(s) are still valid

If I have a program acting as TLS server with a certificate signed by a CA, if one of the issuers in the chain becomes invalidated or the date expires, then how does the program using the certificate ...
2
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1answer
37 views

Are Authenticated Encryption ciphersuites supported in legacy TLS versions older than TLS 1.2?

I have read in a paper that Authenticated Encryption (by this I mean those that support GCM mode or ChaCha20 ciphers) are not supported in versions older than TLS 1.2? I could not confirm this as ...
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1answer
374 views

Simulation of Chosen Plaintext Attack on CBC, Predictable IV with OpenSSL

I would like to simulate the CBC IV attack where the IV is predictable. It's described in the answer to this question: chosen plaintext attack on CBC, predictable iv (Only "Yes" and "No" are valid ...
2
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2answers
794 views

The attacker model of the Lucky13 attack in TLS

Lucky13 is a timing attack against the MAC in the CBC MAC-then-encrypt ciphersuites. In the attack's page: The attacks involve detecting small differences in the time at which TLS error messages ...
1
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0answers
374 views

Encrypt multiple files with OpenSSL securely [closed]

I wish to encrypt potentially gigabytes of data on my pc, and I wish to be able to decrypt and use those files. However, I am a noob, so bear with me. My idea is to use ...
3
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1answer
601 views

Decrypting AES256-CBC with wrong encryption key

Using OpenSSL library is there any chance that decrypting AES256-CBC encrypted data with wrong encryption key will succeed without an error? Asking this because I have read somewhere there is 1/256 ...
3
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3answers
2k views

What is different below two Ciphersuites?

I have two questions; I need an explanation for the differences of below two cipher suites. How do they work with SSL/TLS protocol? (my main concern first one doesn't have '...
3
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1answer
2k views

Why can't decrypt with OpenSSL if salt changed (for CBC and ECB)

A file encrypted with OpenSSL (with, for example, AES 256-bit mode CBC) using the Linux command openssl enc -aes-256-cbc -in texte -out encrypted_texte -k password ...
2
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1answer
376 views

What is the encoding protocol for passphrase protected RSA private keys?

What is the protocol used to encode an RSA key protected with a passphrase? If I generate an RSA key with ssh-keygen -t rsa -b 4096 and do: ...
2
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1answer
442 views

Is this a good PHP encryption Strategy?

I'm writing a multi-tenant application that interacts with a couple of different APIs on behalf of each customer. Obviously, we need to store private keys for these various different APIs in the ...
2
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1answer
2k views
2
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1answer
633 views

X25519 - why openssl shows 253 bits?

When using ECDHE with Curve25519 with openssl: Server Temp Key: X25519, 253 bits I thought when we use X25519, it use 256 bit key. Why openssl shows the server temp key as 253 bits?
3
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0answers
112 views

How to see Diffie Hellman private key used during negotiation? [closed]

I used OpenSSL s_client to connect to a test server. Because OpenSSL generated client side private DH key, I think there will be a way to show the private key or ...
4
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1answer
1k views

The “openssl genrsa” command only generates a private key?

The command : openssl genrsa -out RootCA.key 4096 generates a single file named RootCA.key. When I open the file, it only contains the private key. Then ...
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1answer
248 views

Question about OpenSSL testing for FIPS 186-4 and using BN_generate_prime_ex

I am working on testing my implementation of OpenSSL using the CAVP 186-4 RSA Validation System (RSA2VS). There are tools under openssl-fips-2.0.16/test and I am working on modifying fips_rsagtest.c ...
1
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1answer
119 views

Question about using BN_rand() [closed]

I am working on a project and I'm noticing a peculiar behavior that I was hoping someone could tell me if it is correct or not. I have a program that is trying to generate some random numbers using ...
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1answer
54 views

I am new to digital certificate 509V3 concept. can some one please clarify the below points [closed]

I am using RSA 2048 with SHA 256 primitive in certificate: How to verify the user certificate n + 1 with Root certificate n? why it is required to perform Certificate chain verification? How to ...