IT Security Stack Exchange
IT Security Stack Exchange

Questions tagged [protocols]

A description and set of rules for the ordered exchange of structured information designed with the goal of protecting the security of the system.

322 questions
575
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3 answers

What's the difference between SSL, TLS, and HTTPS?

I get confused with the terms in this area. What is SSL, TLS, and HTTPS? What are the differences between them?
jrdioko
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6 answers

What would one need to do in order to hijack a satellite?

I realise this borders on sci-fi, but there's been some interesting demonstrations regarding security of various satellites. What would be required to hack a satellite (in general terms, any hack really)? Are they all basically connected in the…
Incognito
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Does it improve security to use obscure port numbers?

I recently started a job at a small company where the CTO prefers to host SSH services at obscure, high numbered ports on our servers rather than the well known port 22. His rationale is that "it prevents 99% of script kiddy attacks." I'm curious…
William Rosenbloom
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97
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4 answers

What is ECDHE-RSA?

What is the difference between ECDHE-RSA and DHE-RSA? I know that DHE-RSA is (in one sentence) Diffie Hellman signed using RSA keys. Where DH is used for forward secrecy and RSA guards against MITM, but where do the elliptic curves in ECDHE-RSA are…
Hubert Kario
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77
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16 answers

Ensure that a file can only be decrypted after a specific date

Are there any cryptographic schemes/protocols that would allow me to encrypt a file, make it publicly available, but ensure that it can only be decrypted after specific date? I assume it would be almost impossible without a trusted authority…
Martin Vegter
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8 answers

What is the difference in security between a VPN- and a SSL-connection?

I would like to design a client-server application where the server is placed on Internet. I assume that I could set up the client-server connection using VPN (is it using IPSec?) or using a SSL connection (possibly https). What are the differences…
Jonas
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47
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3 answers

Is Git crowdsourcing cryptographic attacks?

A strong cryptographic hash makes collisions unlikely. Many cryptographic protocols build on that fact. But Git is using SHA-1 hashes as object identifiers. So there are a lot of already computed hashes out there in the public Git repositories of…
MvG
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38
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What changed between TLS and DTLS

What did the DTLS (TLS over UDP) authors have to change so that it could run without TCP? Bonus points: Do any of the protocol difference affect the way it should be used, both in terms of interface but also best-practices?
tylerl
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38
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2 answers

Which protocols exist for end-to-end encrypted group chat?

I am looking for existing protocols for a group chat with two things: End to end encrypted. Just what you would expect: messages are only decipherable by the chat members and message tampering is detected. It should not encrypt each message for…
Luc
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6 answers

Preventing artificial latency or "Lag Hacking" in multiplayer games

There is an attack that some people have dubbed "lag hacking", and its gaining popularity in multiplayer games. There are at-least two ways of creating artificial latency. One method of introducing artificial latency is using a lag switch, where…
rook
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36
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3 answers

IKEv2 vs OpenVPN

I want to ask you for information about the IKEv2 protocol for a VPN connection. I haven't found so much information on the web. I am interested especially regarding the usage on a mobile phone. Is it as secure as the OpenVPN protocol? If yes, could…
Figitus
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32
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2 answers

Is there a standard for printing a public key as a barcode?

Is there a standard for storing a public key printed on paper? Say, I want to hand out business cards with my public key pre-printed on them at a key signing party to help build the web of trust. My understanding is that the standard for storing a…
David Cary
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28
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10 answers

Why can protocols on higher layers be left unchanged?

In his answer to "How does SSL/TLS work?", Luc gives an explanation of how SSL works: SSL (and its successor, TLS) is a protocol that operates directly on top of TCP (although there are also implementations for datagram based protocols such as…
Talpi
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4 answers

How do the processes for digital certificates, signatures and ssl work?

I have been trying to understand how ssl works. Instead of Alice and Bob, lets consider client and server communication. Server has a digital certificate acquired from a CA. It also has public and private keys. Server wants to send a message to…
John Eipe
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27
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Why did TLS 1.3 drop AES-CBC?

I was watching this video about TLS 1.3: "Deploying TLS 1.3: the great, the good and the bad (33c3)" and was somewhat surprised to see that in their effort to provide "fewer, better choices" they dropped AES-CBC as a supported block cipher…
Joel Gibson
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