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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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How to verify Diffie Hellman uses a “Safe” prime

I'm the developer for a web application that was recently pen tested. One of the vulnerabilities reported from the pen test is that our server uses an unsafe Diffie-Hellman prime in our key exchange. ...
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Create self-signed ssl certificate that can't sign other certificates

I have a LAN HTTPS server that I want to give an SSL certificate to. Since it's local-only, a self-signed certificate is sufficient for me. I have previously given it a self-signed root certificate, ...
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Who is responsible for Cipher selection and SSL handshake - Akamai, Load balancer, Publisher dispatcher, publisher

We have a AEM (Adobe experience manager) 6.2 application. I recently been advised to exclude/remove the weak ciphers for strict security policies. But I am not sure where shall I do the configuration ...
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Verify PKCS#7 (CMS) detached signature with timestamp with OpenSSL

I have a PKCS#7 (i.e., CMS) detached signature of a file that is signed by my signing certificate and then timestamp signed by a TSA that is all generated by an application we wrote. I would like to ...
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XML decryption with private key [closed]

I'm trying to understand how xml encryption is working. As much as I've already learned is that usually encryption.xml states which resources are encrypted + it has CipherValue. Cipher value is a ...
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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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Trying to understand/use openssl for decryption

There are many questions around this topic, but I haven't found one that explains exactly my issue. I am encrypting data with AES 128 CBC, but using python and pycryptodome (should have used the ...
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Usage of SSL_CTX_use_certificate

While building a context through openssl, if I do not provide a certificate by using the function SSL_CTX_use_certificate, would all the connections from that context default to anonymous diffie-...
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Openssl command: how to know if the certificate verification is ok [on hold]

I am using openssl tool to check a list of certificates validity. I am looking for the leaf certificate validity using openssl. In this example, I got this output. I see multiple verify results. I ...
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Can a DH param .pem file force the usage of only a single type of diffie-hellman exchange

Is it possible to create a diffie-hellman param .pem file to force the openssl ctx to use only a certain type of dh exchange. For example, I know that it can be used to set the length of the dh key, ...
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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 ...
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OpenSSL Padding Oracle. Specific Ciphers on apache2 seems a little limited

I've seen a lot of articles giving the official explanation on how to prevent OpenSSL Padding Oracles, Usually all of them state that its CBC cipher suites that leave you vulnerable. The following ...
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377 views

What is a “non-stitched” ciphersuite?

From the OpenSSL Security Advisory - 0-byte record padding oracle (CVE-2019-1559) In order for this to be exploitable "non-stitched" ciphersuites must be in use. What is a 'non-stitched' ...
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What makes SoftHSM more security than other software solutions such as OpenSSL? [closed]

I see many people using softhsm just for encryption / decryption rather than using openssl.When I ask people they reply softhsm is more secure. Can anyone say in what ways softhsm is more secure.
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Specify Subject Alt Names in OpenSSL CA

I know you can use -addext with openssl req..... but, are you able to do that with openssl ca....? I would like to be able to add Subject Alternative Names with only one command without having to edit ...
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21 views

decrypting a value read from disk fails with EVP_DecryptFinal_ex:bad decrypt message

Am getting this error "error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt". when I encrypt a buffer and persist it to writing to disk and trying to read the value from disk by ...
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38 views

RFC 5755 Attribute Certificate Validation

According to this explanation: Manually walking through the signature validation of a certificate I'd like to know how is the validation process of an RFC 5755 attribute certificates, because it ...
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What should be OpenSSL .cnf file equivalent of certreq .inf for S/MIME?

Currently I'm using certreq to prepare CSRs for S/MIME certificates. I want to move away from it and start using OpenSSL for key/CSR generation. My .inf file looks like this: [Version] Signature="$...
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EVP_get_cipherbyname returns NULL

When I try to compile my code using OpenSSL 1.1.0i, EVP_get_cipherbyname() is working properly. But when compiled with OpenSSL 1.0.2p, this method always returns NULL and the error is "error:00000000:...
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Nmap / Qualys say 3DES is available, but OpenSSL fails to connect

Running a Qualys scan showed that the IP was vulnerable to a Sweet32 attack, here is the output: TLSv1 WITH 64-BIT CBC CIPHERS IS SUPPORTED DES-CBC3-SHA RSA RSA SHA1 3DES(168)...
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2answers
135 views

HMAC and key size

I generated a keyed hash using HMAC-MD5 and HMAC-SHA256 for an arbitrary file with various keys of different lengths. Do we have to use a key with a fixed size in HMAC? If so, what is the key size? ...
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Netcat script for testing HTTP methods with HTTPS [migrated]

I use this script to test which methods are enabled in a server: #!/bin/bash for webservmethod in GET POST PUT DELETE TRACE CONNECT OPTIONS PROPFIND COPY MOVE LOCK MKCOL; do printf "$webservmethod "...
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How can I create a self-signed certificate with a custom field? [duplicate]

For experiment, I want to add a custom field in a TLS certificate then validate it. Because it is experiment, it will be a self-signed certificate. I use OpenSSL 1.1.0g and Ubunut 18.04. Any hint will ...
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2answers
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Why is OpenSSL verify output depending on source of cert files?

As a test of my TLS/SSL knowledge, I'm trying to verify wikipedia.org's TLS cert. I have downloaded the server-distributed certificate to a file called cert.pem and the root cert (from Globalsign's ...
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Generate symmetric key programmatically using openssl EVP

Am learning OpenSSL EVP API and trying to understand the ways to generate a symmetric key using OpenSSL EVP in C++ program. I have two questions in this regard: 1) To understand what the command ...
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Use self-signed certificate inside of Docker Container for localhost

I've created a self-signed certificate for localhost to use https. I'm running an Apache Docker container which uses the self-signed certificate and the private key. I then installed the certificate ...
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What is a reasonable default_crl_days value for OpenVPN CLR? Why?

I am having trouble finding a definitive answer (with a rationale) on what a reasonable default value for default_crl_days (in openssl.cnf) for use with OpenVPN. The current default is 30 days. But ...
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How to generate the most secure private key? [closed]

I need to generate the most secure private key. Usually I use a command: openssl genrsa -des3 -out mykey.key 2048 Is triple DES secure enough? Is 2048 large enough? Are there any other ways to ...
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How to decrypt AES CCM with salt on Windows?

I have an old file that contains some important information. I know the password, except I forgot how I generated it, and as a result don't know how to decrypt it. Here it is (decoded from it's ...
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Can I use OpenSSL to generate a key from asn1 configuration file without specifying the modular multiplicative inverse q^-1 (mod p)

I'm trying to create this gimmicky public-private RSA key pair where p and q are the same number. I would want to use the asn1 parser in OpenSSL, but I'm required to specify the coeff parameter, the ...
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Why are ciphers using DSS being offered when using DH+AES:!DSS?

When I run the following command on Windows 10 with OpenSSL 1.0.2p installed I receive a curious result back (Formatted for readability): openssl ciphers "DH+AES:!DSS:!aDSS:!aNULL" DH-DSS-AES256-GCM-...
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Extract issuer public key from certificate pem file

I know that a certificate that's been signed by a CA contains identifiers for both the subject and the issuer's public keys: $ openssl x509 -in cert.pem -text X509v3 Subject Key Identifier: ...
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Measuring performance time for TLS handshake

I have this sample code to measure TLS handshake performance time. The result I get is: 3.43 ms. By repeating this for 1000 time, I get the minimum time below 1 ms. I use a device with a public IP ...
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How to extract and verify PDF signature (PKCS7) with openssl?

I would like to detect signed PDFs in PHP and verify if the signature is valid. From this document I have written this PHP code below. What it does is: Extract the PKCS7 code (it works because I ...
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Renewing self signed SSL cert without updating client

I have a server and a single client. I have full control of both, the client is not a distributed application used by the public. For various reasons, I'm having the client use HTTPS to communicate ...
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1answer
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Can I adjust the X509v3 Name Constraints on my internal CA after I have issued certificates? [duplicate]

We have generated an internal root Certificate Authority for our organization and added X509v3 Name Constraints for our domain (example.com) We issued a number of certificates for servers under that ...
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1answer
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Sub-domains TLS certificates and wildcard certificate [duplicate]

1) Is it a good security practice to have a separate TLS certificate for each sub-domain? 2) Is wildcard certificate (i.e. one certificate for many/every sub-domains) a bad practice?
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How to convert this .NET cryptography code to openssl command?

how to sign the message with the private key of the signer using openssl command line tool to get the same result as the code below? using System.Security.Cryptography.Pkcs; using System.Security....
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1answer
57 views

Signature verification against custom CA [duplicate]

I need to (write a program to) verify signature in a (bunch of) signed XML files. NOTE: I am dealing with XML files signed according to 'http://www.w3.org/TR/2001/REC-xml-c14n-20010315', not just ...
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1answer
47 views

How to implement CN/DN certificate validation between two internal servers?

In an internal environment I have two Windows servers which both have Internal CA Signed SSL Certificates used to implement a Mutual Authentication HTTPS connection. Is it mandated that a CN/DN ...
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1answer
466 views

The difference between Subject Key Identifier and sha1Fingerprint in X509 Certificates

I have some SW that extracts certificates data and the SW utilizes OpenSSL. I am confused what is the difference between the subjectKeyIdentifier and the sha1Fingerprint. Both are hash values. My ...
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1answer
230 views

OpenSSL - how to renew certificates in production?

Have a number of private network services deployed on different nodes outside of optionally encrypted mesh systems, like Docker or Consul. The services have high value and should communicate via TLS ...
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2answers
100 views

What is being verified in OpenSSL's SSL_get_verify_result

In OpenSSL the following function is used to verify certs. SSL_get_verify_result I looked at the manual here. But it does not detail what is being verified. Can you clarify to me what does this ...
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What is this error for rootca for wrong system time?

Getting this error for openssl smime verify 140392937076368:error:21075075:PKCS7 routines:PKCS7_verify:certificate verify error:pk7_smime.c:342:Verify error:certificate is not yet valid After ...
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1answer
57 views

Can rootca validity start date be lower than current date?

What will happen if we create rootca X509 certificate with validity date lower than current date? Will date of creation taken into account while cms_verify? What will happen if we change the system ...
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1answer
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Is this CA store related to Ubuntu or OpenSSL

I am checking TLS certificates chain validity against CA sore in this path: etc/ssl/certs/ca-certificates.crt I use Ubuntu 18.04 and OpenSSL 1.1.0g. I need to know whether this CAs store is from ...
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1answer
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How does the public key get authenticated during an ssh session

When using SSH, my private key is stored on my computer safely and my public key is given to the other party I wish to communicate with. I understand that the two keys are mathematically related, and ...
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1answer
47 views

“Self signed certificates” fail, but trust store not

I'm using paho.mqtt.c to connect in a "Self signed certificates" way to a MQTT broker. I have 3 files I use: - CAfile.pem (CERTIFICATE) - PrivateKey.pem (PRIVATE KEY) - Certifcate.pem.crt (...
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1answer
45 views

Do openssl CA certificates get updated with apt-get upgrade?

I use Ubunut 18.04. I need to know if OpenSSL CA certificates that are in this file: /etc/ssl/certs/ca-certificates.crt get updated when I upgrade my system using: apt-get upgrade? I have a ...
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1answer
115 views

How can I use X.509 cross signing to replace a CA?

I have a self-signed CA that I want to rotate the key for. I want to use cross-signing to facilitate this, with gradual replacement of the certificate on the clients so they can still communicate. I'...