Questions tagged [openssl]

OpenSSL is an open-source implementation of basic cryptographic primitives, X.509 certificate utilities, and SSL and TLS protocols.

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REMOTE HOST IDENTIFICATION HAS CHANGED: sftp -v -o HostKeyAlgorithms=... : Cannot use "ecdsa" and "rsa" in parallel

When I connect to my "OpenSSH_8.2p1 Ubuntu-4ubuntu0.4" server alternating using sftp -v -o HostKeyAlgorithms=ecdsa-sha2-nistp256 test-user@localhost and sftp -v -o HostKeyAlgorithms=rsa-sha2-...
0 votes
0 answers
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openssl undefined references

I am getting multiple undefined references when gcc attempts to link my code. I built openssl-3.0.5 using "./Configure --api=1.0.0 no-deprecated linux-x86_64" and I am linking against the ...
6 votes
1 answer
9k views

How to detect whether a CA used EV for a certificate using openssl

I want to download the certificate of a particular hostname and detect whether the CA used EV (extended validation) when issuing it. So far I was not able to find anything that identifies certificates ...
8 votes
3 answers
8k views

File security when encrypting files directly with the openssl command / and what about SHA1 hashing password first?

I've been using this command to encrypt files for a while now: openssl aes-256-cbc -a -salt -in secrets.txt -out secrets.txt.enc Then I type in a password. Can someone tell me, roughly speaking, ...
4 votes
1 answer
616 views

OCSP invalidation of intermediate CA using OCSP_SIGNING

I'm implementing an OCSP server to answer OCSP requests for my custom CA. I already implemented the invalidation of leaves certificates, with the intermediate CA certificate signing the OCSP response, ...
3 votes
1 answer
736 views

I have patched openssl but SSLTest and Nessus say I am still vulnerable to CVE-2014-0224

I am running a server with CentOS 6.5, patched to recent openssl updates via yum update ssl and with indications the current version indeed has the patch to the vulnerability. $ sudo rpm -q --...
0 votes
1 answer
24 views

Connection problems with common name as domain

I was exploring SAN certs and was able to connect to the machine with domains specified in the SAN fields during CSR creation. But I was unable to connect to the machine with the common name specified ...
16 votes
2 answers
24k views

How to set "Not Before" value to past when creating certificate request

We have lots of embedded TLS clients on the field. TLS Servers must be authenticated. Because long power cuts may reset clock of those devices, we have requirement to use certificates with validity ...
0 votes
1 answer
7k views

ssl handshake failure unable to get local issuer certificate

I have an issue with new integration that I am working on it. I should consume a web service provided by external company and this service is over https, so in order to integrate with them, they have ...
0 votes
1 answer
37 views

How to encrypt with a private RSA key in Openssl

The RSA_private_encrypt is deprecated in OpenSSL 3.x. It is not clear how to get the same functionality in 3.x without using the deprecated functions. And, before you ask, IEC_62351-9 Section 9.1.3....
3 votes
1 answer
3k views

Using PSK between an openssl server and client

I'm trying to create a connection between an openssl server and client on my machine using ECDHE-PSK-AES256-CBC-SHA384 What am I doing wrong with these commands? openssl s_server -cipher ECDHE-PSK-...
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Which Keys TLS uses? [duplicate]

I know that in TLS 1.2 the client generates PMS (Pre Master Secret) which is used to get master_secret and Key_Block. Where Key_Block combined with clinet_random and server_random gives us: clientMAC, ...
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What Keys Are Used in TLS 1.3?

In TLS 1.2 the messages sent by client are encrypted under ClientWrite, and the messages send by server are encrypted under ServerWrite. What about TLS 1.3? I don't see any Pre-Master-Secret being ...
2 votes
4 answers
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Is CN/Hostname verification against SSL certificate required for non browser software using openssl & why?

In presence of 'trust certificates' & other attributes .. how important is this? Does OpenSSL implement it now & If not why does OpenSSL not implement? This is between non browser client &...
0 votes
1 answer
173 views

Register a new client with self-signed certificate

I'm trying to understand a series of steps for an authentication system I want to replicate. The steps are executed by this script. To sum up, it does the following: It runs in a Raspberry Pi and the ...
0 votes
1 answer
215 views

openssl SubjectDN parameter, abbreviaton of argument keys and how to add extra ones

openssl command allows to create x509 certificates, and to add subjectDN using the -subj parameter. The parameter accepts a string of slash-delimited values in the form of: "/...
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SSL certificates their public keys and thumbprints

I want to use mTLS, so for testing I created simple API. I wanted to check if I will receive the public key of the certificate after the client sends the certificate to me (the server) as I want to ...
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Securing client/server traffic using self signed certifiates in kind of a "pairing" process

I have two machines, let's call them "Server" and "Gateway", communicating through SSL. A PKI cannot be established, communications outside a company private LAN is not permitted. ...
1 vote
3 answers
713 views

OpenSSL: best way to get sha256 hash of two sha256 hashes

I have two sha256 hashes as hex strings HASH1=b5bb9d8014a0f9b1d61e21e796d78dccdf1352f23cd32812f4850b878ae4944c HASH2=7d865e959b2466918c9863afca942d0fb89d7c9ac0c99bafc3749504ded97730 now I want to ...
0 votes
0 answers
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Derive acceptable key and iv (like pbkdf2) using openssl 1.0 (LibreSSL 2.8.3)

I'm trying to encrypt a string like this: echo "hey" | openssl enc -aes-256-cbc-hmac-sha1 -md sha256 -pass pass:foo -base64 But word on the street is that older versions of openssl are not ...
258 votes
17 answers
409k views

Provide subjectAltName to openssl directly on the command line

Is it possible to provide a subjectAltName-Extension to the openssl req module directly on the command line? I know it's possible via a openssl.cnf file, but that's not really elegant for batch-...
0 votes
1 answer
40 views

Getting fingerprint of certificate signing request

I am aware that I can get the fingerprint of an x509 certificate by typing openssl x509 -in certificate.crt -noout -fingerprint But if I try to get the fingerprint of a CSR (openssl req -in ...
0 votes
1 answer
336 views

OpenSSL: how to get matching subject_hash from a CMS SignerInfo?

So OpenSSL can calculate a hash value for X509 certificates that uniquely identifies this certificate: https://www.openssl.org/docs/man1.0.2/man1/x509.html (argument -hash or -subject_hash) now, if I ...
0 votes
1 answer
108 views

Why is my website certificate not verified by all browsers. Is this related to my CA or just misconfiguration?

I have a certificate signed by https://www.noip.com which I'm using in my website (https://angola.sytes.net), but the certificate is only recognized by some browsers in some places. If you take a look ...
0 votes
1 answer
188 views

Risks with OpenSSL verifying a signature with un-trusted PEM encoded public key

If a website user wants to use WebAuthn, they will start by creating a credential, where their authentication device provides a public key. This key is encoded, and sent back to the server to store ...
0 votes
1 answer
127 views

Does OpenSSL support EAP-TLS privacy

Does OpenSSL support EAP-TLS privacy? It's an optional feature part of rfc5216, section 2.1.4.
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0 answers
38 views

openssl cross-sign non-self signed certificate

I want to cross-sign a third-party certificate (third-party-client.crt) with my own root ca (r1). To do this, I use openssl x509 -in third-party-client.crt -CA /etc/pki/r1/ca.crt -CAkey /etc/pki/r1/...
19 votes
6 answers
75k views

Is it possible to recover a lost passphrase for a private key file?

We have a set of public and private keys and certificates on the server. The problem is that while public encryption works fine, the passphrase for the .key file got lost. So, when trying to execute ...
1 vote
3 answers
202 views

Does EV SSL certificate makes any difference while used instead of self signed ssl in case of API for android app?

I understand that self signed ssl is risky incase of dns spoofing since the attacker may generate a self signed ssl himself and place it in his ip address and it will trigger a warning in the client ...
0 votes
1 answer
1k views

Can PKCS#12 files contain multiple certificate chains?

I know that PKCS#12 files can contain multiple certificates and private keys. However, I could not find any resource where any limit was mentioned for the number of certificate chains or private keys ...
0 votes
0 answers
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Check insecure connection with script

I'm checking connections that traffic data in plain text, example: **http://**site.com but I'd like to check with some script. Does anyone know any scripts or how I can use openssl to find out if a ...
0 votes
1 answer
546 views

SMIME email decryption using a private key - what am I doing wrong?

I have an encrypted .eml file and a private key. I've looked it up a lot on the internet but couldn't find a way to decrypt the email using OpenSSL. I've tried this command: smime -decrypt -in ...
2 votes
1 answer
255 views

Private key differs when creating a pfx container and then extracting it from it

Assuming a private_key.pem and the associated certificate client_cert.pem signed by CA (CSR signed with private_key.pem). Next, I create the pfx container with: # create pfx with private_key.pem and ...
0 votes
2 answers
303 views

Command to check a website is vulnerable to Logjam

I am referring this post https://www.openssl.org/blog/blog/2015/05/20/logjam-freak-upcoming-changes/ and trying to see a website is vulnerable to Logjam or not. I try with www.google.com:443 but I am ...
0 votes
0 answers
35 views

Is it possible to check private key syntax using openssl?

I have a DER-serialized private key. The tool I have to provide the key to gives me algid parse error, not a sequence, and it looks like the problem is that the key is not PKCS#8. The command that the ...
1 vote
1 answer
42 views

Identification of weak and anonymous ciphers with openssl

I'm doing two tests using the openssl s_client command to identify anonymous. I did two tests: One first test: I'm using the following command to anonymous ciphers: openssl s_client -cipher aNULL -...
5 votes
3 answers
8k views

Why is the reuse of the Elliptic curve Diffie–Hellman (ECDH) public server param considered bad?

When reviewing the SSL/TLS configuration using Qualys SSL Labs, I've found that the reuse of the Elliptic curve Diffie–Hellman (ECDH) public server param was flagged. Why is the reuse of the Elliptic ...
0 votes
1 answer
98 views

SSL certificate not standards compliance in Safari

I created a certificate authority on my MacBook, and I'm using it to create a wildcard certificate. I have the root CA added as trusted into my system keychain. On Safari, it complains that the ...
0 votes
0 answers
30 views

Disable client-initiated session renegotiation from the client side

I have a client which connects to a server securely on multiple protocols, namely MQTT and HTTPS. Because of the following CVE, CVE-2009-3555, we decided to disable all client-initiated session ...
10 votes
2 answers
18k views

Public keys on OpenSSL vs PGP?

It is my understanding that PGP permits multiple public keys, and in SSL you can only extract one public key? Is this correct? Is there any brief high level run down between the two. I don't feel as ...
0 votes
2 answers
173 views

Is TLS version related to the server in a Java thick client application?

In a recent pentest (Java thick client), it was discovered by the pentesters that TLS version 1.3 is not supported. I'm investigating why it is not supported, so I was looking in the Java code for ...
1 vote
1 answer
66 views

Interaction of a Code Signature and a Timestamp token from a TSA

I'm currently in the process of writing a program that: Reads a binary file (a C++ program) and creates a SHA256 hash of the data (like a checksum) Use this calculated hash and a self signed CA ...
26 votes
2 answers
25k views

What is the difference between Diffie Hellman generator 2 and 5?

Generating Diffie Hellman parameters in OpenSSL can be done as follows: $ openssl dhparam -out dh2048.pem 2048 Generating DH parameters, 2048 bit long safe prime, generator 2 This is going to take a ...
15 votes
1 answer
12k views

What are the OpenSSL standard Diffie-Hellman parameters (primes)?

I recently generated some custom Diffie-Hellman parameters which are basically just long (in the below case 4096 bit) primes. Those are then used in the key exchange process. I used the following ...
1 vote
1 answer
764 views

Cipher suite is different in “client hello” for the same code running on different platforms

I'm facing a "Alert: handshake failure (40)" error when trying to establish a TLS connection. The error only happens when I run the same application on cloud, it works when I run the application on ...
1 vote
2 answers
80 views

When renewing a TLS certificate (no change to CSR nor private key), will the modulus remain the same?

Here is the scenario, just wanted confirmation that I am understanding it correctly. I have a TLS certificate that will expire soon; Upon renewal, I paid the CA, and they reissued me with a new public ...
56 votes
2 answers
13k views

What do the dots and pluses mean when OpenSSL generates keys?

When OpenSSL generates keys you'll always see a series of periods/dots (.) and pluses (+). openssl dhparam -text -noout -outform PEM -5 2048 ............+........+.....................................
1 vote
1 answer
40 views

Validate HTTPS traffic at later time [duplicate]

I want to capture HTTPS traffic, save it, and validate it at a later time. I want to ensure that at a later time I'm able to validate the HTTPS traffic using the certificate which was presented at the ...
1 vote
1 answer
863 views

how to generate RSAES-OAEP keys?

RFC4055 describes RSAES-OAEP keys and RSASSA-PSS keys. OpenSSL's genpkey utility supports let's you generate RSASSA-PSS keys (you have to set the aglorithm parameter to RSA-PSS) but if it supports ...
0 votes
4 answers
383 views

Which cipher is more secure TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA or TLS_RSA_WITH_AES_256_GCM_SHA384?

TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA supports forward secrecy but it doesn't use GCM mode and use SHA1 TLS_RSA_WITH_AES_256_GCM_SHA384 uses GCM mode and SHA2 but it doesn't support forward secrecy. ...

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