OpenSSL is an open-source implementation of the SSL and TLS protocols.

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Why SMIME decryption works with sender and recipient private key?

Im developing an application, that needs to use SMIME encryption and authentication. I've implemented a decryption system, and am currently testing it. I send the emails with another fully working ...
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1answer
69 views

Can I revoke a client certificate using only it's serial number (not it's crt/pem)?

I've signed and issued some client certificates with my CA. I can now revoke them like so: openssl ca -name ${CA_NAME} -revoke ${USERS_DIR}/${USERNAME}.crt -keyfile $SSL_PRIVATE_DIR/ca.key -cert $...
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2answers
97 views

SSL browser session keys

I am trying to export/write the SSL master secret and keys to a file from the chromium browser. I would appreciate if someone could advice me how to do this. To write the premaster secret we can ...
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76 views

HTTPS: Same certificate, different public key

I have a web server, Debian, and the site uses a HTTPS cert from Thawte. The root certificate meant to be on top of my verification chain is also on the server, in /etc/ssl/certs, because the APT ...
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1answer
101 views

Should 'openssl verify' recognise an exceeded 'Path Length' constraint on a root/intermediate CA?

Background Following the guides here and here I am setting up a multi-level PKI. I have increased the pathlen config to 3, such that I can generate one root certificate that I can use to sign the ...
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129 views

Modify Certificate Subject using OpenSSL x509 Command

I'm building a CA based on the OpenSSL command line tools. I don't want to use the openssl ca tool and its file based database though, instead I create certificates using the openssl x509 tool ...
4
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1answer
101 views

Do I put my subordinate (intermediate) or root CA certificate in my truststore?

I have a server using a certificate signed by my subordinate (intermediate) CA. My java based client needs to put either the intermediate or root CA cert in it's truststore so when it communicates ...
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1answer
228 views

Monitoring HTTP traffic on openvpn server

I have configured an OpenVPN server and can monitor HTTP traffic via tcpdump. Is there any way to monitor the HTTPS traffic as well? Hints Self Signed SSL certificate as root certificate on VPN ...
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1answer
80 views

OpenSSL's EVP functions, more specifically EVP_SealInit

Reference: https://wiki.openssl.org/index.php/Manual:EVP_SealInit%283%29 I want to securely share a symmetrical key between two endpoints using OpenSSL's EVP interface. Transferring the encrypted ...
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2answers
84 views

understanding client certificate - pfx on the general

Today I am given a pfx and told to access a website. I have absolutely no idea what was given to me initially, so please kindly confirm my understanding on a general level 1) the pfx is a container ...
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1answer
44 views

Generate CSR code on local machine

I've tried activating an SSL cert. When it asked for the CSR code, I was thinking about generating this code on local machine because I haven't rented my own VPS yet. The thing is, I'm not sure ...
2
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1answer
113 views

Why does this key get Base64 encoded prior to use?

I wish to have my server encrypt messages to clients who have each provided the server with an RSA public key, as well as having the clients authenticate their messages to the server using their ...
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59 views

Openssl ciphers list sorting and removing

I was playing with a ciphers app to create example list of suites. Looking at the website (https://openssl.org/docs/manmaster/apps/ciphers.html) if I run one of the examples there: openssl ciphers -v ...
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2answers
857 views

How secure is AES-256-CBC with user provided password and initialization vector

From my understanding the IV is used as a previous block for the first block only. But since each block is used by the following this adds significant security is a IV is provided and not based on the ...
3
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2answers
272 views

Use openssl to individually verify components of a certificate chain

This is related to another question, How to verify a signature of one entity by another using OpenSSL CLI? I used openssl s_client -showcerts -connect www.google.com:443 to collect three certificates ...
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1answer
70 views

OpenSSL_encrypt returning an incorrect cyphertext?

I am trying to use the openssl_encrypt function in PHP, this is my code: <?php $message = hex2bin("00112233445566778899aabbccddeeff"); $key = hex2bin("000102030405060708090a0b0c0d0e0f"); $method =...
4
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1answer
39 views

table elements are not encrypted

I read a security book a while ago that said HTML table elements are sent plain text, even if the server connection is https. Is this accurate? I'm thinking about making an on-line purchase from a ...
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24 views

About DROWN SSL attack [duplicate]

I need some clarification regarding DROWN attack: 1) All and only SLLv2 is vulnerable regardless of the chipper strength? 2) How can I check it with Nmap or sslscan? 3) How it's done? I have also ...
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3answers
274 views

How to decrypt SSL traffic with a packet sniffer when I have the private key?

How you do you decrypt ssl packets (traffic) with the private key? I tried to do this with ssldump and openssl but nothing worked.
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3answers
263 views

Why doesn't openssl s_client correctly validate google.com:443?

I try $ openssl s_client -connect www.google.com:443 but it openssl complains that the cert chain is invalid: $ openssl s_client -connect www.google.com:443 CONNECTED(00000003) depth=2 C = US, O = ...
3
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1answer
94 views

How to verify a signature of one entity by another using OpenSSL CLI?

I'm teaching a class about certificate chains, so I download the chain from www.google.com which has 4 certs. I want to demonstrate how the dependencies work from issuer to subject by showing that ...
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5answers
2k 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 ...
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177 views

MQTT (Mosquitto) certificate SSL23_GET_CLIENT_HELLO:unknown protocol [closed]

I'm been desperately trying to get my MQTT clients to connect to my MQTT broker which is set up with a certificate from a CA. To be able to get the CA certificate, I've used the letsencrypt python ...
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1answer
80 views

Is reseeding OpenSSL CSPRNG necessary if using RAND_bytes?

I read that cryprographic secure PRNG (CSPRNG) need a random seed to provide random output. Looking at OpenSSL that seems to be archived by RAND_poll() and random data is fetched with RAND_bytes(buf, ...
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2answers
131 views

How to have client encryption without server encryption key

I want to build a service where people can message each other via their mobile device so that they encrypt all of their information on their device and not on my server. Basically I want to two people ...
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1answer
74 views

Regenerating dhparam periodically

Does it increase connection security if I regenerate the dhparam files used with NGINX on our servers periodically e.g. every week? What issues may arise from this? Is there any benefit in doing ...
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1answer
83 views

ECDSA implicit certificate using OpenSSL

I am trying to generate implicit ECDSA certificate only for signing and verification using OpenSSL. I tried google but I am getting many research papers. I understood that A messages need to be signed ...
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1answer
153 views

CSR with only public key with openssl

So I have been doing my research and haven't found anything specific enough to my problem. As the question title states, I want to make a CSR with only the public key. What I have been able to do is ...
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1answer
4k views

How to manually test for DROWN attack?

We know that the official website serves the user with a way to test our servers against DROWN attack. Apart from that, I am looking for a manual testing method to check any servers against this ...
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3answers
150 views

Are there any problems with using CAMELLIA, IDEA and SEED based cipher suites on a web server in 2016?

I have recently seen CAMELLIA, SEED and IDEA cipher suites in use for HTTPS on a web server and am unsure what to suggest to the owner. The keys in use are all over 128 bits in length and standard ...
8
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1answer
227 views

Cache Bank conflicts and CacheBleed: What is there to worry about?

It seems that researchers have announced yet another vulnerability regarding OpenSSL, separate from the DROWN issue, called CacheBleed. You can view the research paper here. How does it work, and ...
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2answers
21k views

What is DROWN and how does it work?

There is a new recent attack "on TLS" named "DROWN". I understand that it appears to use bad SSLv2 requests to recover static (certificate) keys. My question is: How? How can you recover static ...
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33 views

RSA decryption with Private and Cert files

What I have : The cipher message, the plaintext message, and something that could be the RSA Private & Cert. (I can create as many couple ciphered/plaintext as I want) I would like to be able to ...
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1answer
158 views

Protect against client-initiated renegotiation DoS in OpenSSL/Python

According to https://blog.qualys.com/ssllabs/2011/10/31/tls-renegotiation-and-denial-of-service-attacks, servers supporting SSL/TLS connections and allowing client-initiated renegotiations are ...
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0answers
29 views

Finding the EMSA-PKCS1-v1_5 DigestAlgorithm field in the x509 certificate

From the RFC - https://www.ietf.org/rfc/rfc3447.txt A.2.4 RSASSA-PKCS1-v1_5 For each OID, the parameters field associated with this OID in a value of type AlgorithmIdentifier shall have a value ...
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1answer
54 views

How is hash used with AEAD-based ciphers in TLS? [duplicate]

Look at this cipher: ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(128) Mac=AEAD It uses AES-GCM for encryption and data origin authentication (according to RFC-5288), so no ...
3
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1answer
49 views

self-signed CA next to signed CA?

What I'm trying to do is implement client-certificate authentication on my website (running on Apache). From this question I understand that it's not possible to generate a client certificate myself ...
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41 views

Followup to one-liner to create cert request with SAN

I've been trying to use the OpenSSL line from this older thread to create a CSR with subject alternative name: Provide subjectAltName to openssl directly on command line If I run the line from that ...
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1answer
107 views

Is there any way or tool to check whether a particular iOS app is implementing SSL Pinning functionality?

I'm just learning the iOS security. This is completely a beginner question. I'm trying to figure out whether there is any particular way to check if an iOS app is implementing SSL Pinning ...
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0answers
294 views

How does openssl pkcs12 command work?

I have been using certutil dump command successfully to check the order of pfx certificate chain. Recently I tried doing the same using openssl pkcs12 command and it give me exactly the opposite order ...
5
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1answer
79 views

Is OpenSSL generating Diffie-Hellman parameters that are safe for use in TLS or SSH servers?

I would like to generate Diffie-Hellman parameters on a Debian GNU/Linux "Jessie" 8 with OpenSSL. Lets assume the system CSPRNG was seeded with some real random data. On such a system, is the result ...
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1answer
38 views

Diffie Hellman prime attributes

If I generate a Diffie-Hellman prime openssl dhparam 512 -text (deliberately of small size to keep the paste size below small; I know minimum is 2048 and up), what are the different parts of the ...
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0answers
58 views

Log to file my own SSL traffic coming from websocket

I have to decode and capture my own traffic that come from a websocket WSS listening on port 7072, when I use browser to connect to my data provider. My idea is: to redirect traffic to serverpush....
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2answers
150 views

sharing private key sTunnel

All of the sTunnel guides and implementations at work do the same thing, they say once the private key and the public cert are created on the server, you need to cat them together and then share with ...
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1answer
105 views

OpenSSL key derivation

I'm trying to manually decrypt DTLS packets sent by OpenSSL. The cipher suite used between the server and the client is TLS_RSA_WITH_AES_256_CBC_SHA256 and my understanding is that the IV used by ...
4
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1answer
515 views

What are the main advantages of using LibreSSL in favor of OpenSSL

What are the main advantages of using LibreSSL vs OpenSSL? As I understood LibreSSL is a fork of OpenSSL: LibreSSL is a version of the TLS/crypto stack forked from OpenSSL in 2014, with goals of ...
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2answers
121 views

Banner grabbing OpenSSL versions with OpenSSL

With the recent news about a new OpenSSL vulnerability (affecting 1.0.2 only), I'm looking to conduct some research and I was wondering if there was an way to identify what version of OpenSSL a server ...
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78 views

How to convert the PRIVATEKEYBLOB structure generated using CryptExportKey to bigendian?

Private-key BLOBs, type PRIVATEKEYBLOB, are used to store private keys outside a CSP. Extended provider private-key BLOBs have the following format. PUBLICKEYSTRUC publickeystruc; RSAPUBKEY ...
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2answers
128 views

what is the different between X.509 certificate and 2-way SSL? or both are same? [duplicate]

Can anyone clarify what is the difference between an X509 certificate and two-way SSL? or both are same?
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1answer
92 views

Server providing two different SSL certificates

When I check on browser for a site example.com, I see that site has a valid certificate, not expired, with validity till end of 2016. At the same time, When I scan for the same domain on the port 443 ...