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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AES-GCM - what are “Payload Length” and “AAD Length”

For the AES-GCM mode within many cryptomodules, their FIPS-validation certificates list the options: Payload Length: 504, 512, 1016, 1024 AAD Length: 0, 504, 512, 1016, 1024 For example in OpenSSL, "...
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default value for rsa_padding_mode in openssl cms command [closed]

I am trying to generate the signature for a file using openssl cms command. Wanted to understand what is the default value for rsa_padding_mode. I did not specify anything for this parameter and I ...
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38 views

How is a digital certificate generated?

I understand that the role of a Certificate Authority is to SIGN (not encrypt) a certificate. The signed certificate will theoretically contain: Plain text of data, including the server's public key ...
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1answer
76 views

Double 3DES/TDES Encryption

If 3DES/TDES (officially TDEA or Triple DEA - Triple Data Encryption Algorithm) encryption is used twice, using 6 different keys K1-...
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1answer
39 views

Do I have to know RSA padding scheme in advance when verifying signature with EVP_Verify*?

Is there a way to figure out what RSA padding type was used on signature during verification (when calling EVP_VerifyInit, EVP_VerifyUpdate and EVP_VerifyFinal) or is it a matter of convention which ...
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1answer
75 views

Why aren't Diffie Hellman public keys used for authentication?

So I have been reading about Diffie Hellman and specifically the MitM attacks that it is vulnerable to. I am aware that these are solved currently in ssl for instance by using rsa signatures to ...
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1answer
55 views

Asymmetric or Symmetric encryption

I'm currently looking into OpenSSL and its API and I'm not really familiar with cryptography. So I was looking at the example on asymmetric encryption of an envelope. And it says the message is ...
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27 views

TLS client authentication from static client image

I'm trying to implement mutual authentication for a TLS connection between a server (ONOS OpenFlow controller) and multiple clients (OpenFlow switches). I'm restricted in that I must create a single ...
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38 views

Error propagation in CBC [duplicate]

I am doing an error propagation experiment with the CBC mode.I have encrypted a 100 byte text file with openssl. I made the 55th bytes of my encrypted file corrupted.As per theory the corresponding ...
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1answer
84 views

Requirements for RSA key parameters

Recently I'm working with a chinese vendor for POS devices and their devices use 2048bit RSA keys for signing binaries. I had to generate a public/private pair (so I can sign my own binaries) and I ...
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1answer
61 views

openssl encryption salt length

when i was reading the latest source code of openssl, i found openssl enc has an 8-byte (64-bit) salt length; because the same ...
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Default RNG used by openssl for certificate generation [duplicate]

I have generated a certificate using openssl with the below command. ...
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1answer
65 views

Can the OpenSSL random number generator be considered cryptographically secure? [duplicate]

The OpenSSL Random Number generator documented here uses an OS-provided entropy source coupled with a MD5 hash function. Does it impact the quality of randomness to use a broken cryptographic hash ...
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2answers
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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 ...
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336 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
89 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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56 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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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
102 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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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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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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48 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
95 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
208 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 ...
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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
828 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
44 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
268 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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71 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 ...
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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
346 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
3k 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
221 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 ...
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1answer
710 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
574 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
450 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
165 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. ...
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1answer
883 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
257 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 ...
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1answer
149 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 ...
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1answer
633 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
262 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
40 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 ...
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1answer
39 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
433 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 ...
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2answers
832 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 ...
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422 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 ...
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1answer
667 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 ...
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3answers
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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 '...