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13
votes
3answers
715 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
0answers
19 views

What is the link between ssl ciphers I use (string length, strength of ciphers) and nginx performance? [migrated]

All is in the question. I am wondering whether how using each ciphers or another would impact performance. Is there a huge impact ? Is the impact linked to the type of content deserved ? (static or ...
0
votes
2answers
101 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
41 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
votes
2answers
82 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 ...
1
vote
0answers
67 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 ...
0
votes
2answers
246 views

nginx recommended ssl_ciphers

I am looking for some advice on setting the ciphers for nginx with SSL. What would you recommend for a good compromise between security and compatiblity at the moment? I have made some research but ...
2
votes
1answer
231 views

Which forward secrecy cipher suites are supported for TLS1.0 protocols?

May I know which are all forward secrecy ciphers supported in TLSv1.0 protocols?
1
vote
1answer
74 views

Can TLS fallback work with server side support only?

I have patched my server with OpenSSL 1.0.1j for the Poodle vulnerability. Been reading the spec on TLS_FALLBACK_SCSV. From what I can tell in order for TLS fallback prevention to work properly it ...
4
votes
1answer
309 views

Why does my openssl connection fail with elliptic curve cipher ECDH-RSA-AES128-SHA?

I am using openssl example server and client with specific cipher in ubuntu 14.10 pc. The openssl version is 1.0.1. When I use the RC4-SHA cipher in both sides, the connection is established ...
3
votes
2answers
152 views

Choosing TLS / SSL cipher suites - What considerations are there?

Most of the advice on choosing cipher suites I find tends to be one of these forms: Here's a string to paste into your application, or Here's a list of 30,000-foot generic criteria to use ("favor ...
-1
votes
1answer
53 views

Calculating the breakability of a given encryption method

I will soon be doing a very important project for school. The main goal of my project is to find a mathematical way to calculate the breakability of a given encryption method of ciphertext. Is there ...
6
votes
2answers
722 views

Is TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 a safe cipher suite to use?

Is TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 a safe cipher suite to use for a TLS 1.2 connection to a Tomcat server? What are potential weaknesses or better alternatives? I am looking for a cipher ...
0
votes
1answer
444 views

JSSE recommended cipher suites

In the wake of POODLE I am reviewing the configuration of a number of Tomcat servers running on the JSSE connector. In order to work out what ciphers JSSE supported I wrote a little snippet that ...
2
votes
2answers
773 views

Can Poodle be fixed in SSLv3 or will it go the way of TLS compression?

Is TLS_FALLBACK_SCSV going to be the fix for servers that wish to keep SSLv3 enabled? If not what actions are being taken, if any, that address the vulnerability besides disabling SSLv3?
1
vote
1answer
479 views

Poodle - possible to protocol downgrade if SSLv3 is disabled but still have SSLv3 ciphers enabled?

My title pretty much sums it up. If I have: A server with the SSLv3 protocol disabled BUT still have SSLv3 ciphers enabled. Would that mean that a protocol downgrade attack can still occur?
1
vote
1answer
322 views

Can Cipher Suites defined in TLSv1.2 be negotiated by clients that only support TLSv1.0?

If my server has only the cipher suites enabled which are defined by TLSv1.2 does that force a client to also use TLSv1.2 or else not be able to connect or can the connection fallback to TLSv1.1 or ...
1
vote
1answer
370 views

Add Cipher Suite support to Chrome/ Chromoium?

I would like to know how to add Cipher Suite: TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA support to the new versions of Chrome? Since Chrome v25/26 Google stopped the support of Cipher Suite: ...
3
votes
1answer
4k views

How to disable cipher RC4 in ubuntu 12.04

I have been doing Network Scan for our box and Ncircle reported SSL Server support RC4 ciphers for SSLv3. Based on that I did a search and I plan to add to /etc/apache/conf.d/security the following: ...
2
votes
1answer
715 views

openssl ECDHE-RSA… cipher suite selected while using RSA server cert and ECDSA client cert

The scene: s_server using RSA certificate. s_client using ECC-ECDSA certificate. Client authentication is required (option -Verify set on s_server) Cipher-suite selected after handshake is ...
0
votes
1answer
558 views

How are TLSv1.0 ciphers negotiated as TLSv1.2?

I'm a little confused about something I am reading in Bulletproof SSL. "TLS 1.2 is the only protocol that allows suites to define their PRFs. This means that for the suites defined before TLS 1.2 ...
1
vote
1answer
140 views

ECDSA/RSA certifcates and cipher selection

In this image can someone tell me if a standard RSA certificate can support the EC*_RSA ciphers listed? If so do you create the typical RSA keys when you are creating the CSR? Also I am fairly ...
2
votes
1answer
145 views

Drawbacks to only using TLS 1.2 ciphers in OpenSSL

I understand you would not want to do this as it would limit compatibility for older devices and platforms. However if someone were in an all TLS1.2 environment, say a very well managed internal ...
1
vote
1answer
542 views

Display browser requested cipher suites from OpenSSL

I installed OpenSSL locally and used s_server command to start a server by using self signed certificate created by OpenSSL as well. The command I used to start a https server is OpenSSL> s_server ...
1
vote
1answer
564 views

Using AES as a Stream Cipher

I need to send a lot of small messages that are usually between 128 bits and 256 bits long, and each message is encrypted with a separate 128 bit AES key. Therefore, to send each message with the key ...
5
votes
1answer
524 views

How did SSLv3 get AES?

IANA maintains a registry of TLS cipher suites at TLS Parameters. TLS provides TLS_RSA_WITH_AES_128_CBC_SHA, its value is {0x00, 0x2f}, and its available in TLS 1.0 and above. The AES cipher suites ...
0
votes
0answers
49 views

BKSQ block cipher

I'm trying to implement the BKSQ block cipher (similar to AES) but to do so I need the inverse mixcolumns operation, therefor I need to inverse the 2x^2+2x+3 operation. e.g for the AES it is c(x) = ...
0
votes
2answers
108 views

How secure would this method be considered for password storage

Ok I am currently storing the passwords in most secure way I could think of. With use of Encryption and Hash. The passwords are first generated by user as plain-text with minimum length of 6 ...
0
votes
1answer
559 views

Openssl ciphers SHA384 and AEAD

When running the command: openssl ciphers -v I get a long list of cipher combinations. I'm having issues interpreting some of them. An example is: DHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=DH Au=RSA ...
1
vote
3answers
122 views

Is it possible to stack encryption algorithms with SSL?

SSL supports a number of ciphers, but is it possible to stack/nest the ciphers, and process the plaintext in stages? My adversary may be able to easily crack one or more of the stages, but to decode ...
1
vote
1answer
525 views

What is default mode for AES encryption [closed]

What will be the default mode for AES encryption if we don't use any specific mode like ECB, CBC, OFB, CTR, etc. and just carry out the encryption without specifying any AES encryption mode.
1
vote
1answer
2k views

Which is the Best Cipher Mode and Padding Mode for AES Encryption? [closed]

As per PCI-DSS 3.4 requirement: For storing Credit Card Data Strong Cryptography should be used. I decided to use AES Encryption which is a strong and mostly recommended crypto for encrypting ...
0
votes
0answers
21 views

What SSL/TLS ciphers do each version of Android support? [duplicate]

What ciphers do each Android device support? Update: More specific not SSL or TLS versions but the actual ciphers such as ECDHE-ECDSA-AES128-GCM-SHA256, etc. Android 2.3? Android 3.x? Android ...
45
votes
4answers
30k views

“Optimal” Web Server SSL Cipher Suite Configuration

Over the last couple of years there have been a number of changes in what would be considered an optimal SSL cipher suite configuration (e.g. the BEAST and CRIME attacks, the weaknesses in RC4) My ...
1
vote
1answer
170 views

Block Cipher Pseudocode

Suppose that I have a block cipher whose key size is 128 bits. but the block length is eight bits. Let E(m’) be an encryption oracle that encrypts by running our “short” block cipher in CBC mode. ...
1
vote
1answer
286 views

Why does not GSM use any stream cipher mode (OFB, CFB)?

If I understand correctly GSM uses A5/1 stream cipher. My question is why doesn't it use a stream cipher mode like OFB or CFB?
11
votes
2answers
500 views

Forward secrecy for kids

In the Scouts, it is popular to use secret codes to write messages (which are simple ciphers). I want to introduce Forward secrecy to the kids so they can use it with these ciphers. So, if the ...
8
votes
4answers
10k views

Identify and disable weak cipher suites

i'm asking a question on a subject that is pure chinese to me..sorry in advance A security scan result prior to the deployment of a web application on windows server 2008 R2 has raised the below ...
3
votes
1answer
220 views

Are all cipher suites with rc4 in them intrinsically flawed?

I've been wondering lately if RC4 is so flawed in all its forms, why is it that it is still being supported by all major browsers per default? Why does the typical chrome browser prefer ...
2
votes
2answers
267 views

For DHE_RSA_.. Cipher Suites what is RSA used for?

In addition to achieving PFS with DHE, we want as little as possible to be revealed when the server's private key is revealed. So, what is RSA used for in DHE_RSA cipher suites? What does the server ...
4
votes
1answer
5k views

TLS v1.0 best cipher for OpenVPN setup

I'm trying to setup OpenVPN with as much security as I can. I'm in the process of selecting a cipher for OpenVPN. Which is the safest one, tls-cipher DHE-RSA-AES256-SHA or tls-cipher AES256-SHA? I've ...
1
vote
1answer
315 views

Export ciphers prevalance

I would like to clarify the consequences of not supporting export ciphers. When I run a qualys ssl test on ebay.com, I notice that the following cipher suites are supported. ...
0
votes
1answer
2k views

“Must have” and “Preferred Cipher” suites terminology

I have received the following advise to set cipher suites to suitably mitigate Beast attack on a newly setup Apache HTTPD server. Preferred ciphers: RC4-SHA, RC4-MD5 Must Have Ciphers: ...
4
votes
1answer
625 views

Is possible that a TLS server send more than one certificate to the client for the same site?

What I'm trying to archive is enable ECDSA and DSS ciphers in my site, but at the same time not depend just of self signed certificates, so I could sent to my client more than one certificate and them ...
4
votes
1answer
1k views

What could be the order of these ciphers following as first criteria the security and just then the performance?

I need some guide to decide in which order I must put the following ciphers if I want prioritize security and in cases of tied, consider performance to decide. ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 ...
5
votes
1answer
3k views

What block ciphers and algorithms are now safe? [closed]

I work for a large non-US based international organisation. Regarding the recent leaks about the NSA breaking most encryption on the internet, we now know the US and UK governments are actively ...
2
votes
1answer
828 views

Configuring GCM cipher suites in Jetty based server

I have a Jetty based secure http service, and I wish to support GCM cipher suites. I know that Jetty internally use JSSE based ciphers, and there are many GCM ciphers coming with JSSE as documented ...
0
votes
3answers
2k views

Hardened SSL ciphers for Nginx as AWS/Cloudfront Custom Origin

Based on recommendations, we recently attempted to harden our Nginx SSL configuration against BEAST/CRIME/BREACH attacks with the following stanza: ssl_prefer_server_ciphers on; ssl_ciphers ...
0
votes
1answer
560 views

How to get an exhaustive list of ciphers for TLS 1.0, TLS 1.1 and TLS 1.2

After TLS 1.0, there have been a number of RFCs e.g RFC 5932, RFC 6430 etc. Is there any place where one can get an exhaustive list of ciphers for each of the versions. Or at least an exhaustive list ...
4
votes
1answer
4k views

Is using RC4-MD5/RC4-SHA as SSL ciphers enough for most purpose?

In the AWS ELB, I have uploaded a cert and only selected "RC4-MD5" + "RC4-SHA" as the ciphers and scored A in the ssltest [1] If I using the default ELB setting, I can only score a C Since I am not ...