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Questions tagged [cipher-selection]

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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server negotiating TLS1.3 but sent TLS1.2 ciphersuite

I sent a client hello indicating TLS1.3 support, and it contains a list of all ciphersuites that support TLS1.3, TLS1.2 and TLS1.1 And consider server negotiated TLS1.3 indicating serverHello....
hjhjh's user avatar
  • 51
2 votes
3 answers
223 views

If I control both sides of a connection, is there any reason to support alternate cipher suites?

If I have a system where I have 100% control over the client operating system and the server operating system, is there any use case for enabling more than one cipher suite (or any of the options that ...
Peter Turner's user avatar
0 votes
2 answers
1k views

docker daemon reports 'tls: unconfigured cipher suite' for Nginx reverse proxy of Artifactory Docker registry

I am migrating to Artifactory on RHEL8 as a Docker remote repository, i.e. Artifactory is a proxy for a docker registry hosted through Jfrog.io. We have a legacy registry with config in /etc/docker/...
bbaassssiiee's user avatar
0 votes
1 answer
260 views

Why is ECC (Eliptical Curve) an `--expert` feature in PGP?

Eleptial Curve is now included in PGP. However when I run gpg2 --full-gen-key, I get Please select what kind of key you want: (1) RSA and RSA (default) (2) DSA and Elgamal (3) DSA (sign only) ...
Evan Carroll's user avatar
  • 2,955
0 votes
1 answer
600 views

TLS 1.3 Cipher Suites: authentication algorithm unspecified?

I was looking at Cipher Suites indicated on SSLLabs and I noticed something, here is a result for google.com (for instance): With TLS 1.2, examples of Cipher Suites are: ...
Weier's user avatar
  • 101
1 vote
0 answers
1k views

Disabling weak cipher suites in Tomcat does not work as expected

I have to get rid of so called "weak security" in a Tomcat application. A penetration test identified services that accept connections with insecure TLS encryption and hashing algorithms: ...
MichaelW's user avatar
  • 161
0 votes
1 answer
1k views

Cipher Suites settings wrong order?

I'm trying to setup a custom order of TLS cipher suites according to this Microsoft list, on Windows Server 2022 but the outcome is not the one that I was expecting. After using the powershell to ...
cadobe's user avatar
  • 3
0 votes
1 answer
225 views

How to create a cipher string that doesn't contain AES and CAMELLIA ciphers?

I am trying to learn about cipher lists and how to order them. I am new to this. I have gone through this doc. I don't get some of the things mentioned in it. Maybe this post can clairfy it. I want to ...
Abhishek Dasgupta's user avatar
0 votes
1 answer
2k views

P-384 vs. SHA384

Forgive my inexperience with encryption, I've been researching this for the better part of the morning and still cannot find a smoking gun answer. A vendor is requesting that we verify a website we ...
wr mem's user avatar
  • 1
1 vote
4 answers
6k 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. ...
dawklrw's user avatar
  • 11
2 votes
2 answers
624 views

Java support for TLS_DHE_RSA_WITH_AES_128_CCM

My test tool uses java and I need it to use TLS_DHE_RSA_WITH_AES_128_CCM. Does standard java (Oracle) support CCM cipher suites? I am seeing oracle links mentioning CCM but am not able to make it work....
Amal Jesudas's user avatar
2 votes
2 answers
1k views

Cipher suite choice on macOS on Apple Silicon

I have a postfix mail server that accepts these cipher suites: tls_high_cipherlist=ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256: ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384: ...
Synchro's user avatar
  • 727
0 votes
1 answer
598 views

How does TLS use hashing from the negotiated cipher suite

I am trying to understand why TLS only uses hashing algorithm like SHA-384 instead of using an HMAC instance like HMAC-SHA-384. If I understand correctly, this cipher suite (...
A.Ho's user avatar
  • 25
1 vote
0 answers
328 views

Should I manually select protocol and cipher?

I'm writing Java code for a decentralized network. (Proof of concept code here.) Each node generates its own self-signed certificate, to be used both server-side and client-side in every connection. ...
Erhannis's user avatar
  • 111
5 votes
1 answer
9k views

How are key exchange and signature algorithms negotiated in TLS 1.3

In TLS 1.2, the cipher suite lists the algorithms for everything (key exchange, signature, cipher/MAC). So by choosing a suite, all the algorithms will have been negotiated. And I can see them from ...
Linda Wu's user avatar
6 votes
4 answers
16k views

SSH Server Configuration Best Practices?

I have been tasked with reviewing the settings of an SSH server, I'm currently trying to figure out what are the best practices, and I'm having a bit of trouble finding a good answer. I keep finding a ...
Mizex's user avatar
  • 63
1 vote
0 answers
724 views

Are Brave Browsers Sync encryption parameters secure enough?

I am considering switching over to Brave and maybe also use it's sync feature for settings, and maybe even passwords if it's good enough. I do use a password generator but out of laziness I happen to ...
jaaq's user avatar
  • 125
1 vote
1 answer
2k views

Should hashing algorithm used for X.509 certificate's signing match the algorithm used in the communication

I've seen this but the related answers don't answer my question. For TLS 1.2 is the hashing algorithm specified in an X.509 certificate's cipher suite used for the signature inside the certificate or ...
axk's user avatar
  • 135
3 votes
1 answer
419 views

Why can SSH negotiatie two different encryption and authentication algorithms?

I recently found out, that according to the RFC, SSH can negotiate two different cipher (and MAC) algorithms for server-to-client-encryption and for client-to-server-encryption (check section 7.1. for ...
mat's user avatar
  • 1,272
0 votes
1 answer
341 views

Is it possible to view the cipher suites offered on my behalf by a MITM proxy?

I'm trying to discover what cipher suites are being offered by my corporate proxy. It's set up as a man in the middle so my "secure" connections are to it, and it attempts to create a ...
Disbeliever's user avatar
0 votes
1 answer
299 views

Find out the least insecure mutual cipher algorithm

I have set the cipher algorithms for ssh on my server to just [email protected], [email protected] and [email protected] Now my IntelliJ fails with this error: failed: unable ...
rubo77's user avatar
  • 2,390
2 votes
2 answers
5k views

OpenSSH: Meaning of cipher with email address @openssh.com

When using OpenSSH server (sshd) we specify allowed ciphers, host key algorithms and MACs. Some of those ciphers have an email address appended, for example [email protected] as opposed to aes256-...
TheCooocy's user avatar
  • 123
1 vote
2 answers
1k views

When connecting via SSH, does the Diffie-Hellman key exchange take place over an unencrypted TCP session or does encryption occur before the exchange?

I'm a cybersecurity student and I'm eager to understand the basic processes of an SSH session. I wrote down the stages to the best of my ability but need help understanding what happens right after ...
Dequavis's user avatar
0 votes
1 answer
339 views

what is the link between server certificate and cipher list advertised by server for nmap command?

Nmap out put for google.com. ssl-enum-ciphers. TLSv1.2: ciphers: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA (ecdh_x25519) - A. TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 (ecdh_x25519) - A. ...
user231290's user avatar
1 vote
1 answer
232 views

What is the purpose of TLS cipher suites pairing? Why are they paired the way they are?

Why are there predefined sets of cipher suites. Why is creating your own cipher suites not recommended.
RealTimeEngineer91's user avatar
0 votes
2 answers
1k views

Remove less secure ciphers from WHM by decrpyting different convoluted references to the same ciphers

I have previously removed less secure ciphers from WHM (Web Host Manager) however it has been a while and I want to learn how to fish, not be handed a fish. The trouble seems to stem from the fact ...
John's user avatar
  • 119
1 vote
0 answers
17k views

TLS handshake failure (40) solved by removing intermediate certificate from server?

I'd like to better understand my workaround, and confirm that it's secure. Problem I have a crt file containing a root and intermediate certificate installed on my server (I have limited access to ...
Jayz7522's user avatar
  • 111
0 votes
0 answers
205 views

Does the entire certificate chain need to be signed with the agreed upon cipher under TLS? [duplicate]

Security Newbie, I'm using OpenSSL for my client, and noticed that when testing it against Bad ssl's sha1-intermediate test, it accepts it although the agreed upon cipher is ...
david-hoze's user avatar
2 votes
1 answer
491 views

Force specific encryption cipher for S/MIME mails

I have a number of contacts who can only decrypt 3DES, when it comes to S/MIME encrypted mails. I'm aware that this is by far not ideal, but better than no encryption at all. My problem is, that I ...
GarlicCheese's user avatar
1 vote
1 answer
540 views

How do I verify the supported ciphersuites of a TLS server that only accepts POST requests?

I'm currently trying to get a bidirectional TLS 1.2 connection working between 2 local Karaf-based XMLRPC servers that by design only accept POST requests. The environment is Windows 10 and both ...
Nzall's user avatar
  • 7,563
1 vote
1 answer
445 views

Why are the following two sets of ciphers "different"?

openssl ciphers -v 'ECDH+AESGCM:DH+AESCGM' gives: ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=RSA Enc=AESGCM(256) Mac=AEAD ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=ECDSA Enc=...
Marki's user avatar
  • 137
0 votes
0 answers
800 views

Openssl using the cipher parameter result in handhsake failure

When i use Openssl to connect to facebook.com I see 'ECDHE-ECDSA-AES128-GCM-SHA256' ciphersuite used. openssl s_client -connect www.facebook.com:443 SSL handshake has read 3280 bytes and written 373 ...
Redhat's user avatar
  • 23
3 votes
3 answers
354 views

Ensuring all network services on a device use strong TLS cipher suites

(This is hypothetical, but based on a real-life problem I've had) Context: I am developing an (embedded) device which includes a few exposed network services. I'm responsible for security, not ...
Josiah's user avatar
  • 241
0 votes
0 answers
184 views

Can someone explain the significance of Certificate Signature algorithm in the selection of Cipher suite in a TLS communication? [duplicate]

Can someone explain the significance of Certificate Signature algorithm in the selection of Cipher suite in a TLS communication?
Redhat's user avatar
  • 23
2 votes
0 answers
101 views

Best luks setup disk [duplicate]

I want to encrypt my disk but I want to know what is the best configuration, I currently use ths: cryptsetup -v --cipher serpent-xts-plain64 --key-size 512 --key-file=- --hash whirlpool --iter-time ...
Gabriel Caltzontzi suarez's user avatar
2 votes
1 answer
289 views

IPsec installed algorithms

What happens if a laptop and a server don't have a encryption algorithm in common? Does IPSec abort the connection or does it always have default algorithms?
Dario Blair's user avatar
18 votes
1 answer
15k views

How do I know which cipher suites can be disabled?

I have just performed a test on my personal webiste via SSLlabs.com and I'm apparently supporting some weaker ciphers. I've managed to improve several settings (like CAA), but I'm getting stuck at the ...
Martijn's user avatar
  • 359
0 votes
1 answer
491 views

Determine if cipher suite is weak [closed]

I'm wondering if there is a way I can determine if a cipher suite is weak using python code. For example given this cipher suite as input: TLS_RSA_WITH_AES_256_CBC_SHA I would want my code to return ...
jim's user avatar
  • 103
3 votes
1 answer
880 views

How to filter ciphers based on ssl certificate?

I have many ssl certificates. On one of the certificates I run the command openssl x509 -in cert.pem -text -noout it shows: Signature Algorithm: ecdsa-with-SHA256 Public Key Algorithm: id-ecPublicKey ...
harsh3547's user avatar
1 vote
0 answers
261 views

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 ...
ynerdy's user avatar
  • 111
1 vote
1 answer
440 views

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 ...
confused_unicorn's user avatar
3 votes
1 answer
239 views

What means that the same ciphersuite is both enabled and disabled in Java JSSE?

I am looking into documentation for JSSE ciphersuites in Java. https://docs.oracle.com/en/java/javase/11/security/oracle-providers.html#GUID-7093246A-31A3-4304-AC5F-5FB6400405E2 ...
Alameyo's user avatar
  • 31
-5 votes
1 answer
5k views

How to disable obsolete/insecure TLS_RSA ciphers to harden Chrome? [closed]

Multiple vulnerabilities have basically obsoleted TLS_RSA, CBC and QUIC implementations. February 9, 2019: "Seven researchers from all over the world found --yet again-- another way to break RSA ...
Tyler's user avatar
  • 445
11 votes
3 answers
12k views

What are the 'P' values in some cipher string?

Most of the cipher strings I see are in the format: TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 ...
user58446's user avatar
  • 563
0 votes
1 answer
1k views

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-...
sethmlarson's user avatar
  • 1,487
2 votes
1 answer
7k views

What are the best ciphers in terms of performance for SSH tunnel?

From a security standpoint, there are few good cipher options to use with SSH, such as ChaCha20, AES 128/256 GCM/CTR. As I understand (please correct me if I wrong), all of these offer pretty strong ...
ovk's user avatar
  • 123
3 votes
1 answer
2k views

Is `tls_preempt_cipherlist = yes` in postfix a good idea nowadays?

Postfix' own documentation says it may cause issues, but only mentions "Windows 2003 Microsoft Exchange clients". Everything else I've found (first was CheckTLS, as far as I've been able to find, that'...
Henrik supports the community's user avatar
2 votes
0 answers
3k views

TLS1.2, weak cypher suites and PCI DSS V3.2.1 compliance

Are below cypher suites, which are part of TLSv1.2: TLS_RSA_WITH_AES_128_CBC_SHA TLS_RSA_WITH_AES_128_CBC_SHA256 TLS_RSA_WITH_AES_128_GCM_SHA256 TLS_RSA_WITH_AES_256_CBC_SHA ...
Chris's user avatar
  • 161
0 votes
1 answer
442 views

Understanding Cipher suite prefixes

I have been lately reading cipher suites and how it works. I figured how it works in the web servers and there is a doubt regarding the prefixes used in the order. How are RC4-SHA and RC4+SHA ...
KESHAV K's user avatar
1 vote
1 answer
3k views

Understanding SSL Cipher suite in Apache

On reading the documentation Apache documentation. A cipher suite example has been given : RC4-SHA:AES128-SHA:HIGH:MEDIUM:!aNULL:!MD5 I have understood the explanation given by them. My question is ...
KESHAV K's user avatar

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