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

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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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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 ...
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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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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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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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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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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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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 ...
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1answer
47 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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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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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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227 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 ...
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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
34 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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46 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 ...
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2answers
107 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
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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 ...
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1answer
207 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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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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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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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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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 ...
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SSL Labs report question: Is “Insecure Renegotiation” possible if weak cipher suites are not available on server?

On one server, we have removed weak cipher suites and insecure protocols to try to pass SSLScan / SSL Labs. One outstanding problem is Insecure Renegotiation. I read that: The Apache Software ...
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1answer
140 views

Is it possible to create a pem file server certificate from the result of openssl s_client -showcerts?

I know it is possible to list server certificates from a client via openssl s_client -showcerts. So, my question is, is it possible to create a valid ssl server certificate from this without needing ...
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41 views

How to avoid writing .pem while signing a csr?

I am using following command to sign a certificate, openssl ca \ -in client.csr \ -keyfile server.key \ -cert server.crt \ -outdir ./some_dir \ ...
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OpenSSL gmail - receiving Please log in via your web browser and then try again

Using openssl as below when I do EHLO auth login and then enter my username and password I get the following error: Please log in via your web browser and then try again. Learn ...
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94 views

Where in the CSR is the public key?

I am reading http://www.akadia.com/services/ssh_test_certificate.html In step 2 openssl req -new -key server.key -out server.csr server.key is generated earlier using openssl genrsa -des3 -out ...
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Why does SubjectAltName not turn up in my CSR?

Does the CSR generated contains the SubjectAltName I have configured the openssl.cnf file to support extensions and when i dump the CSR i can see subject is available not the SubjectAltName This is ...
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2answers
161 views

With openssl des3, what are the passphrase parameters?

I'm using OpenSSL's des3 tool to encrypt a file, e.g. openssl des3 -salt -k SUPER_SECURE_PASSPHRASE < inputFile > outputFile Everything's working, but now I have to choose a final, fixed ...
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1answer
84 views

How do I change LUKS backend to OpenSSL?

I know there is a way to do it, but I don't know how to do it: the default backend for LUKS is libgcrypt and I want to test it with the openssl cryptographic library. I was told that there is a ...
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1answer
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Why is the Key Derivation Function important?

Let's consider this openssl command : openssl enc -aes-256-cbc -pass pass:PASSWORD Why is it important to have a good Key Derivation Function? This answer to another question suggest that GnuPG is ...
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1answer
103 views

How does Windows certificate manager verify a file's certificate, if the root certificate is not in the store?

I'm working on a project which requires certificate verification for executable files. I have created my own trusted root certificate store, and used openssl to perform verification. However, when I ...
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1answer
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Is SSL really insecure on most of the web? This report seems to suggest so [duplicate]

The Wikipedia article on TLS article has a tremendously long list of attacks against SSL. A table on that article shows a survey from September 2015. If you look at that survey, it shows that nearly ...
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51 views

How to patch haproxy for OpenSSL vulnerability USN-2830-1

This is regular security task, I have a number for servers running HAproxy on ubuntu 14.04 LTC on AWS. Since USN-2830-1 is a OpenSSL vulnerability I believe we must patch our HAproxy instances, but on ...
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214 views

If I set http.sslVerify to false in git, then will the connection be secure?

If I set "http.sslVerify false"(in .gitconfig file) in git, then will the connection be secure? In between, we are using pfsense firewall and squid+squidgaurd for web-filtering. Is this a good path ...
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Is 8192 Diffie-Hellman overkill?

I've finally ran SSL server test on my server and was presented with: This server supports weak Diffie-Hellman (DH) key exchange parameters. Grade capped to B. So I tried to generate stronger ...
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1answer
39 views

Salt generation for stream cypher

Sorry if this is an elementary question but I could not find a direct answer. For end-to-end encryption of messages that wait temporarily on a server and where the sizes can vary from just a few ...
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AES keyfile size

I would like to encrypt files using a key file instead of a password. What I would do is: 1) Generate X random bits using openssl rand X > mykey 2) openssl enc -aes-256-cbc -in secretfile -out ...
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MITM or Something Else?

Problem: When a given set of user devices (tablets/laptops) downloads files from a certain server from outside the host server's country, downloads are sporadically and routinely interrupted. The ...
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1answer
85 views

How to change the default/preferred SSL cipher in Linux?

Is there any way I could change the default/preferred cipher for SSL, so that any application/process in Linux which uses SSL would have to use that specific cipher (RC4-SHA for example) for it's ...
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1answer
72 views

Why does not appear the public key from certificate?

I'm creating a certificate in LAMP, the public key is: Public Key: 30 81 89 02 81 81 00 CC CB 64 54 C2 FA A3 7A 81 36 5F 1B D5 10 81 75 B7 42 02 31 83 B1 D5 5A 76 72 6A 77 BE 62 69 16 AB EB 39 66 B5 ...
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2answers
113 views

Using Self sign certificate in internet

Basically the purpose of SSL cert is for trusting each other. If I have an application that only a few clients I know can use, is generating self sign certs enough? Or do I really need to sign with a ...
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82 views

OpenSSL ecparam generates same private key every time?

Currently I am trying to make my web server as secure as possible and I am testing different cipher suites on the server side, some of them using ECDHE key exchange. When generating private EC keys, ...
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1answer
47 views

What was the first version of Android to use OpenSSL (and what version was it)? What was used prior?

Android 1.6 source is the earliest I can find that references openssl (i.e., has OPENSSL_VERSION[_TEXT] defined The script I ran to get these versions was: $ git clone ...
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CMS signed data OpenSSL verification error

I have a CMS signed data that is successfully verified through Java BouncyCastle library. When trying to verify through OpenSSL, I am getting the following error: >openssl smime -verify -inform ...
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1answer
84 views

Are fields of a root CA certificate checked?

During SSL server validation, it seems that the only fields of X509 certificates found in trust stores that are actually used are the "Common Name" and the "Public Key". I'm not talking about any ...
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Benefit of having multiple DH moduli of same length?

What is the benefit of having multiple Diffie Hellman moduli of the same length in OpenSSH's moduli file? In the distributed moduli file there are around 40 primes for each length to choose from ...
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Why does Java allow AES-256 bit encryption on systems without JCE unlimited strength policies if using PBE?

It's fairly standard knowledge that due to the cryptography export controls, Oracle JRE ships with "limited" cryptographic strength enabled as listed in the JCA Documentation. For AES, the default max ...
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How to read certificate chains in OpenSSL

I'm trying to understand how to read the output of OpenSSL commands. Currently, I am trying to understand how Certificate Chains work. When I give the command (using a standard ca bundle) openssl ...
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Filtering safe primes for Diffie Hellman on OpenVPN

When creating Diffie Hellman parameters for OpenSSH, there's a two-step process which looks like this to generate and filter secure primes for Diffie Hellman key exchange: ssh-keygen -b 4096 -G ...