RC4 (Rivest Cipher 4) is a type of stream cipher.

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Why are weak Cipher Suites still in use by clients, particularly mobile apps?

I am examining the collection of cipher suites that some mobile apps use (Client Hello) and I noticed that the majority of them include the TLS_RC4_128_MD5 and TLS_RC4_128_SHA. According to the OWASP ...
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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 ...
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1answer
109 views

How much of an impact will the RC4 cut off make?

Quick disclaimer - Student, cryptography is a weak point. So, can someone explain exactly how this will work? The way I see is is that if a user is attempting to connect to a server using RC4 only ...
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Prevent BEAST attack without RC4 cipher suites

It is common practice to prevent the BEAST attack using the following ciphers in Apache SSL configuration: SSLCipherSuite RC4-SHA:HIGH:!ADH Unfortunately, RC4 has been found to be flawed and it is ...
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xls RC4 encryption password from key

I asked this question on stackoverflow, but thought it may be more appropriate here. I have a key from a RC4 encrypted excel sheet (xls), along with the salt, and hash, etc. and I have decrypted the ...
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Use of RC4 on real time application

I need to use a stream cipher in my application. I know using the same key for many messages is not a good practice for stream ciphers (RC4). But I also dont want to make a new key all the time so I ...
3
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RC4 encrypt many messages with same password

I would like to ask if it's insecure to encrypt many different messages sent over the Internet encrypted by RC4 with the same password. If it is insecure, then if I encrypt the first message with the ...
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1answer
280 views

How could a publicly available stream cipher (RC4) be kept secret so long?

I'm reading about the cryptographic function called RC4. Apparently, its method was kept secret from 1987 until 1994 despite being available to the public for licensing and use. How did it stay ...
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Can someone explain a little better what exactly is accomplished by generation of DH parameters?

I'm setting up a node.js server: https.createServer({ ... ciphers: 'ECDHE-RSA-AES128-SHA256:AES128-GCM-SHA256:RC4:HIGH:!MD5:!aNULL:!EDH', honorCipherOrder: true }, app).listen(443); ...
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1answer
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What to do when Google disables SSLv3 and RC4?

I've read this article from Google's Online Security Blog, and it says that Google will disable support for SSLv3 and RC4. Here's the reason: SSLv3 has been obsolete for over 16 years and is so ...
3
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1answer
220 views

Writing your own John the Ripper module

I have a script in C, which is able to determine the password of certain data. It uses HMAC and RC4 algorithms to encrypt the given password and then compares that later to the given data. If they ...
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Should Mozilla SSL3/RC4 whitelisted sites be blacklisted by admins/users? [closed]

As of Firefox 39, Mozilla has dropped support for SSL3 and RC4... and whitelisted 519 (!) non-compliant sites: ...
3
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1answer
190 views

RC4 encryption of torrents safely

Torrent clients offer encryption of traffic using RC4, and people consider this very safe to hide traffic information from ISP. Now since I have a website with SSL encryption, I know that RC4 has a ...
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1answer
195 views

CryptoAPI to CommonCrypto with RC4

I have cryptographic code used in the Windows platform, which uses the Crypto API functions and need to convert this to using Common Crypto on OS X. Essentially the original code is this, with error ...
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1answer
503 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?
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Disadvantages of disabling RC4 in SSL/TLS [closed]

Other than requiring more server resources, are there any disadvantages of disabling RC4 from being using by an Apache webserver? My primary concern is preventing access from older browsers.
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What is the impact of removing TLS_RSA_WITH_RC4_128_SHA from my server's cipher suite?

I run a website that supports many clients via webservices. I'm setting up some new certificates and load balancers and when doing ssllabs's server test, it's flagging all my ciphers as OK except ...
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1answer
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Are there any known vulnerabilities in PPTP VPNs when configured properly?

PPTP is the only VPN protocol supported by some devices (for example, the Asus RT-AC66U WiFi router). If PPTP is configured to only use the most secure options, does its use present any security ...
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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 ...
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2answers
262 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 ...
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For use with RC4 how do I combine a reused key and an initialization vector

I am an a-level student writing an encryption program using an rc4 implementation I have written myself. I have the basic algorithm coded correctly (and I have checked that some ciphertext for a given ...
27
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1answer
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How to describe RC4 'bias' to non-tech people

I'm looking for the 'plain English' version of 'bias' as used in the context of the RC4 weakness. I know that RC4 generates a string of psuedorandom bits over, for instance, http(s) traffic. If you ...
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1answer
720 views

How strong is PDF security/encryption?

I want to securely convey a PDF document containing sensitive information from my system to another system. The latter is operated by a different person, whom I trust. However, this person does not ...
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1answer
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SSL Mixed Scripting Vulnerabilities and XOR Attacks

Given that RC4 is a stream cipher (I'm pretty sure the details of its inner workings don't matter for the sake of this argument) and the existence of Mixed Scripting / Mixed Display (web applications ...
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657 views

Why do the banks all use weaker TLS suites? [closed]

I've been checking out various TLS certificates lately and noticed that most of the banks seem to have the following two issues: 1) They do not offer perfect forward secrecy 2) They are still using ...
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1answer
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PFS on nginx: only RC4 gets used (TLS_ECDHE_RSA_WITH_RC4_128_SHA)

I'm trying to configure my webserver for perfect forward secrecy. I'm using ssl_ciphers ...
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716 views

Google's usage of RC4

I was reading about Google's usage of RC4 and an answer on stackexchange website stated the following: I know Google uses RC4 for most of its services, and this is the reason one shouldn't keep ...
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3answers
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Does it make sense to keep RC4?

I know that the RC4 cipher when used with SSL is vulnerable to certain attacks, which in the worst case scenario could result in authentication tokens being stolen. But RC4 is also recommended as a ...
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1answer
328 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 ...
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4answers
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Remove RC4 from SSL/TLS ciphers in Chromium

Recently I started to live without RC4 within my Firefox session. Discussion about it can be found here. While it is quite easy in Firefox (Enter about:config and then rc4), I found no possibility to ...
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TLS: RC4 or not RC4?

I was reading another interesting article by Matthew Green today, saying that if you're using RC4 as your primary ciphersuite in SSL/TLS, now would be a great time to stop As far as I'm aware ...
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Clients breaking after avoiding RC4-MD5

As per http://projects.webappsec.org/w/page/13246945/Insufficient%20Transport%20Layer%20Protection , we have been recommended to stop using RC4-MD5. The clients supported by our Application are IE ...
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How does DHE-RSA-AES256-SHA compare to RC4 as the Cipher for SSL?

I read a lot of issue [1] currently stating that RC4 is broken and is at risk. I just checked my web server (nginx) and it is using the default settings, which is DHE-RSA-AES256-SHA How does this ...
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RC4 bias protection with padding in TLS

On the answer to my previous question about RC4 vulnerabilities in TLS, Thomas Pornin gave a great answer, in which he said: One way to "fix" RC4, which has been suggested many times, is to drop ...
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Implications of having a service account in AD use RC4 rather than AES for Kerberos?

Bear with me, I know this is sloppy, but here is the back story: We have a partner that uses Jira and is using spnego with a custom auth back-end that expects certain group membership in the token. ...