For questions about the step of the SSL/TLS handshake where the cipher is negotiated between the client and the server. This tag could also be used for questions about which ciphers to support in your application / configuration.

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-7
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0answers
58 views

How strong is this cipher suite? [on hold]

Are there any shortcomings in this SSLCipherSuite? EECDH+ECDSA+AESGCM EECDH+aRSA+AESGCM EECDH+ECDSA+SHA384 EECDH+ECDSA+SHA256 EECDH+aRSA+SHA384 EECDH+aRSA+SHA256 EECDH+aRSA+RC4 EECDH EDH+aRSA RC4 !...
4
votes
0answers
127 views

HTTPS Cipher selection considerations [closed]

I went through various online docs, e.g. SSL and TLS Deployment Best Practices, regarding the "right" selection of cipher suites for a website. The attached picture shows my selection of cipher suites ...
0
votes
0answers
27 views

ISO 9564 Approved Encryption Algorithms for PIN, why symmetric block ciphers?

I am currently researching best practices in designing a potential PIN management solution for a financial services application and began looking into ISO 9564 as a source of requirements. One of the ...
1
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2answers
29 views

logging available client side cipher suites from Apache tomcat?

When planning to remove a cipher suite, is there a way to log what cipher suites are available to the clients that talk to my web server? The idea is to know in advance that before some cipher is ...
0
votes
2answers
52 views

TLS_RSA_WITH_AES_128_CBC_SHA on Windows XP

Let me first say, I know XP is bad and dead. That said, I was wandering if a software written using .NET could make TLS 1.0 connections that use the TLS_RSA_WITH_AES_128_CBC_SHA when running on ...
3
votes
2answers
54 views

When moving beyond SSL3 is not possible, what cipher suites are immune to POODLE?

I understand that anything not using CBC will work, but are there any such modes? I'd also like to avoid weak stuff like RC4/5 and MD5 so preferrably ciphers that use sensible functions. On a SSL 3.0 ...
7
votes
1answer
119 views

Is the order of cipher suites related to the client's preferences ?

I am wondering if the order in which the cipher suites appear (from top to bottom) in the ClientHello message, and the client preference are relevant. So for example in the picture I have attached, is ...
1
vote
1answer
206 views

How to disable weak cipher suits in java application server for ssl

I have a custom Java application server running. I am seeing that there are some weak cipher suites supported by the server, for example some 112-bit ciphers. I want to disable those. Where can I do ...
2
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0answers
39 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 ...
0
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2answers
208 views

Cipher suite selection for compatibility with http/2, and TLS 1.0-1.2

I have been attempting to configure my site to have http/2 support, but I kept having to remove cipher suites because of the blacklist. Eventually, I got the list whittled down sufficiently. The ...
9
votes
2answers
287 views

Why does Google prefer ECDHE-RSA-AES128-GCM-SHA256?

I want to configure my new mail server secure as possible and wondering about the used cipher while connecting to Googles SMTP server. I'm curious why they prefer the cipher ECDHE-RSA-AES128-GCM-...
3
votes
1answer
155 views

Firefox & Chrome Strong Ciphers

Of the following ciphers for RSA authentication, Firefox and Chrome do not use stronger than ECDHE-RSA-AES128-SHA256. ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(256) Mac=AEAD ...
5
votes
2answers
114 views

What are the use cases for anonymous SSL cipher suites?

SSL supports several anonymous cipher suites such as TLS_DH_anon_WITH_AES_256_GCM_SHA384. When these are used, no authentication is performed and no certificates are exchanged. This means that if they ...
4
votes
3answers
137 views

Can browsers connect HTTPS w/ the NONE cipher?

I came across a mention of the NONE cipher being possible/available for HTTPS. Is it supported by any browsers for accessing any web-sites over the https:// address scheme? (What would be a snippet ...
0
votes
2answers
398 views

Bitwise cipher Cryptography

I'm doing an online cryptography course. There is a question in which it is given that the encrypted text for; OwBPAAQXAE9UC0FVBQxODgZSCUUMAQwCCApYRBJZBR0LDhoAGApPHQAUAQNZRAJPGwQbDQBDDREKQA== Is ...
0
votes
0answers
53 views

stream cipher & e-banking

As I read on internet, I ran into these two question. Yet, I thought about it but still don’t know how to tackle it. May I have your help? (a) During an e-banking transfer the bank uses a stream ...
20
votes
1answer
2k views

TLS Bicycle Attack - What cipher is free from flaws to use?

Recently a novel attack on TLS stream ciphers was developed by Guido Vranken, dubbed Bicycle and referenced in this Websense's blog post. It was based on a characteristic of stream ciphers that says ...
1
vote
1answer
99 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 ...
6
votes
1answer
378 views

SSH ciphers, MAC and key-exchange (and pen-tests thereof)

At work we've been trying to move our external-facing services away from a policy of inclusivity (where we tried to accept as many people as possible) to a more security-focused setup. The first step ...
0
votes
3answers
299 views

SSL certificates using modern cipher suite vs obsolete cipher suite

I am shopping around for a SSL certificate and I took this screenshots from Chrome and Is the second site certificate showing errors less secure than the other not showing errors?
2
votes
1answer
202 views

What ciphersuites does Java 6 support out of the box that are not broken?

I have a legacy application which sits on Java 6(!), and talks to Apache 2.2.15 on RHEL 6.4. (An upgrade for Java 6 is on the cards, but not before go-live date.) We have pentest fails for a weak ...
1
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0answers
158 views

How to import Comodo certificates into Keystore?

I'm trying to create a Keystore. I've already generated a Private Key, generated and sent a certificate request to a CA (Comodo), and I've received a ZIP file from the CA (Comodo) containing four ...
5
votes
1answer
118 views

Dynamically decrypting files

Is it possible to store (video) files encrypted (using AES or similar) in the cloud and have clients' browsers download those files and dynamically decrypt them to start viewing them whilst they are ...
2
votes
1answer
120 views

Chrome/FF not negotiating advanced ciphers?

Ran into a weird problem trying to lock down our AWS ELBs today, specifically trying to deprecate all support for SHA-1. Having removed options like AES256-SHA ECDHE-RSA-AES256-SHA (among others) ...
2
votes
2answers
2k views

TLS_RSA_WITH_3DES_EDE_CBC_SHA reported as 112 bits

I am no expert in this area but after some searching I am not too sure about the solution. An external vendor doing a pentration test on our server reported that we have ...
1
vote
2answers
95 views

Dovecot TLS connection handshake ChangeCipherSpec

I added a virtual domain to our mail server today then did a check of the Dovecot TLS connection security. The test was done from a remote host using Thunderbird. I captured the connection with ...
2
votes
0answers
115 views

Deciphering “easy” ciphers without hints [closed]

I've been keen on IT Security for a long time now and I've learned a lot about networking & security. However trying a "decryption challenge" I'm lacking what I think is basic encryption/...
0
votes
2answers
1k views

Meaning of mod_ssl cipher suite put together and order of preference

I read cipher suite description of mod_ssl, and understood the meaning of alias and keywords like ! + etc. But I am unable to understand how to read ALL:!ADH:!EXPORT:!SSLv2:RC4+RSA:+HIGH:+MEDIUM:+LOW ...
0
votes
2answers
120 views

Encryption in case of distributed architecture

I have application infrastructure as follows - web client -> load balancer -> Apache (web server) -> Weblogic (application server). I could understand that in case of HTTPS request, SSL handshake ...
2
votes
1answer
587 views

Setting node.js TLS ciphers vs observed behavior

I have a node.js server that I'm configuring for TLS 1.2. I set the following options in the config of my https server: ciphers: 'ECDHE-ECDSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256:DHE-RSA-AES128-...
3
votes
3answers
296 views

Cipher used for request data encryption used by browser

Please note that this is not about how SSL communication happens between browser (I researched and understood it) and client but other aspects. Using Digicert's SSL mechanism explanation I have ...
3
votes
3answers
2k views

How do browsers negotiate SSL/TLS connection parameters?

For the purpose of this question, let assume that an SSL/TLS connection has 4 parameters: protocol, symmetric encryption method, asymmetric encryption method, MAC. During the negotiation of SSL ...
2
votes
2answers
137 views

Secure communication in SHTF

I am a prepper. I am preparing for a situation where there will be no rule of law and where I can't rely on the government for all my needs. This naturally involves storing food, water, and items for ...
1
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0answers
80 views

Are there any tools out there that can 'trick' keyloggers?

Are there any tools out there that can 'trick' keyloggers? I was wondering if there's any 'enigma-style' tools available along the lines of providing time-randomised keyboard mappings. For example: ...
3
votes
3answers
4k views

How to pass cipher list to OpenSSL s_client

How we can pass a cipher list to the OpenSSL s_client program? We can pass single cipher by this: openssl s_client -cipher 'ECDHE-RSA-AES256-SHA' -connect www.google.com:443 But how to pass a list ...
1
vote
1answer
253 views

What's RSA and ECC's role in TLS 1.2? [duplicate]

I'm trying to figure out what is RSA and ECC used for in TLS 1.2 cipher suites. Let's take TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 for example, communication between server and client would look ...
2
votes
2answers
314 views

Openssl ciphers: what does Au=ECDH mean?

I am trying to get a grasp on different stages of SSL. I have referred to some fantastic answers about how SSL/TLS works and specifically about authentication mechanisms, and numerous other sources. ...
3
votes
1answer
575 views

Is CVE-2013-2566 a practical attack against RC4 or still conceptual?

Is CVE-2013-2566 a practical attack against RC4 or still conceptual and does it only apply to WPA/TKIP?
1
vote
1answer
285 views

How to change personal cipher/digest preferences of existing OpenPGP key in GnuPG?

The OpenPGP key contains a list of personal algorithm preferences (the meaning of the numbers can be decoded in RFC 4880): # gpg -a --export "foo@example.com" | gpg --list-packets | fgrep 'pref-' ...
0
votes
1answer
436 views

Google Chrome obsolete cryptography

I have a apache server running and following configuration for ssl: Header always set Strict-Transport-Security "max-age=31536000; includeSubDomains" SSLProtocol -all +TLSv1.2 SSLCompression Off ...
3
votes
0answers
368 views

OpenSSL: Allow CBC ciphers for TLS but prevent for SSL3

In my server application using OpenSSL, to prevent the poodle attack, I added an option to fully allow/prevent SSL3 protocol. SSL_CTX_set_options(ctx, SSL_OP_NO_SSLv2); //Prevent SSLv2 ...
1
vote
1answer
213 views

Choosing a cipher and MAC for an SSH connection

The cipher and mac selection according to this are in some sort of order in a config file. How do the client and server know that they are using the same ones though? Is this information exchanged in ...
4
votes
1answer
1k views

DHE_DSS vs. DHE_RSA

I have been studying to learn about various cipher suites and their performance; I'm wondering about the difference between DHE_DSS_AES256_CBC ciphersuites and DHE_RSA_AES256_CBC ciphersuites. I ...
3
votes
1answer
3k views

Creating a private key with OpenSSL and encrypting it with AES GCM

My goal was to create a private key and to encrypt it with a strong cipher. That key would be used as a root certificate for an internal Certification Authority. However, eventhough openssl supports ...
3
votes
1answer
373 views

Does OpenSSH use export ciphers?

With all of this talk of 'FREAK', no one has mentioned OpenSSH. It implements libraries from OpenSSL (until recently, anyway). Why aren't people talking about this? is there even a way to configure ...
14
votes
3answers
1k views

Should I worry if my credit card payment processor's server allows only weak SSL cipher suites?

I tested their server using https://www.ssllabs.com/ssltest/ and, apart from the disappointing "B" rating (it handles financial transactions, after all), the server only allows the following two RC4 ...
0
votes
2answers
248 views

Why use anything other than RSA for transmission encryption?

Being fairly new to the cryptography and data security space, I have sampled a few "Introduction to cryptography" sites/textbooks and they all seem to start in the same general way: This is a Caesar ...
3
votes
1answer
211 views

Does TLS fallback only keep from downgrades to SSLv3?

I have read the RFC on this and can't seem to find what I am wanting to know. When implemented, if a client and a server support TLS fallback protection, does it only keep them from downgrading to ...
0
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2answers
274 views

RC4 support in SSL configuration

GitHub recently improved its SSL setup by removing RC4 support: To keep GitHub as secure as possible for every user, we will remove RC4 support in our SSL configuration on github.com and in the ...
2
votes
1answer
177 views

Can TLSv1.0 ciphers be used with SSLv3?

Can TLS cipher, such as TLS_RSA_WITH_AES_256_CBC_SHA, suites be used within an SSLv3 connection? For example, say the client and server both support TLS but the connection is downgraded to an SSLv3 ...