Questions tagged [transport-security]

Transport security about establishing a real time secure channel from a sender to a receiver. Transport security generally requires more protection and a more intricate protocol than securing data at rest. Well known attacks against transport protocols include MitM attacks and CBC padding oracle attacks.

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Nonce-misuse-resistance scheme applied after the fact to AES-GCM for defense in depth?

This is a follow-up to a previous question about encrypting IV/MAC results from AEAD ciphers. I have a system I'm working on that needs to use standard (NIST/FIPS) cryptography, at least for its ...
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Should i hash or encrpt the data first? Why? [duplicate]

Lets say alice is trying to send data to bob , should alice first hash the data and then encrpt or vice versa
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Secure Communication

Focus: I have to design a secure keep alive communication protocol and was wondering if it was necessary to sign the ciphertext after the session key has been generated as an attacker will not know ...
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What is the “single-letter characterization of the secrecy capacity”?

I'm reading a paper [1] in which secrecy capacity are being discussed under the following terms: A single-letter characterization of the secrecy capacity that holds for the general case remains ...
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Security of HOTP over an unencrypted channel for controling an actuator

I have a simple on/off actuator that I want to control remotely. I want to use available hardware: a pair of microcontrollers connected to a pair of wireless transceiver modules. Can HOTP algorithm ...
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Understanding hybrid cryptography's concepts: signing and CA

After learning about symmetric encryption, public-key encryption, one-way hash, digital signature and digital certificate, I was tasked to think of an imaginary hybrid cryptosystem. I was thinking ...
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Generate a per data shared secret vs per session

I have read about SSL that they persist the shared-secret for the entire session. However, someone in stackoverflow suggested a way of generating a shared secret for each data to send and then send ...
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What attacks does future secrecy protect against?

Consider messaging between 2 parties. A sequence of messages are exchanged between the parties using encryption. We consider an attacker that has at a minimum a log of all the (encrypted) messages ...
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why do we asume that in the registration process communication is over the secure channel?

I was reading some research papers and saw that in Registration phase/process it is always assumed that communication is over the secure/private channel, whereas, all of the phases communication is ...
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What is Perfect forward secrecy?

I have read that when a user contacts an entity like a bank, it creates a pre-master key and then selects a master key for subsequent communications. Can the lack of PFS, create a security flaw if ...
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Does it make sense to have long SSH Key with shorter Passphrase?

If we encrypt our data with a longer SSH key which is protected by a shorter passphrase (with a decent entropy), then the limiting factor is entropy of the passphrase. So why do we use a longer key at ...
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Key transport vs key encapsulation?

What exactly is the difference between key transport and key encapsulation? Either they seem to be used interchangeably, either I'm mixing stuff up.
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Secure communication channel recommendations

I'm working on a cryptography-related project, which uses ECC (elliptic curve cryptography). And one of the things that I need is a "secure" communication channel for two entities. I need someone to ...
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Establishing a shared secret over a unsecure channel

Is it possible to establish a shared secret between two devices if the devices have no prior knowledge and no secondary secure channel to exchange information? Assume a Dolev–Yao model for the ...
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TLS: Risks of using a NULL cipher with encryption implemented in application?

We have a browser-launched JNLP/WebStart application that is no longer able to establish client-server CORBA/IIOP communications across TLS 1.0/1.1 due to relying on a cipher suite that uses an ...
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Signal Double Ratchet - How can Alice send 2+ messages in the beginning of the Signal Protocol?

I'm studying about Signal Protocol and I had a doubt in Double Ratchet Algorithm. This section describes how to derive the receiving and sending key messages. Alice is initialized by Bob public ...
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X3DH Protocol - How can the receiver calculate the Shared Key?

I'm reading about Signal Protocol and X3DH Protocol. In the X3DH Protocol, Alice sends a initial message to Bob encrypted with a Shared Key(SK). This SK is calculated using (this section): ...
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1answer
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There is a protocol similar to SRP but where a part of the secret is stored on the client side?

SRP is very useful but if our DB is leaked, an attacker could brute force a user's password with his associated salt/verifier found in the DB. I'm searching a solution to prevent this. My first idea ...
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X3DH protocol - What are One-time prekeys for?

I'm reading about Signal Protocol and this protocol uses the X3DH Protocol to establish a shared secret key between the two parties but I couldn't understand why we use one-time prekeys in the flow. ...
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Is there an escrow-like mechanism that doesn't involve a trusted 3rd party?

We know that escrow mechanisms are easy to implement when it involves a trusted 3rd party. For example if A and B don't trust each other they can simply send their goods to C whom they both trust. ...
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What's a good security schema for many to many communication?

Assuming you have a "typical" group chat-room, with n participants connected together by a server (the server handles message routing). Would be a good security schema which would allow for encrypted ...
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TLS Finished message: is it MAC or HMAC

In several academic literature, the term Finished MACs is used frequently. I wonder, is it really a MAC or HMAC? I am looking at literature in TLS 1.2 vs. TLS 1.2 specs. The specs of TLS 1.2 Finished ...
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TLS1.3 encrypted handshake

I read that TLS 1.3 supports encrypted handshake. Is it achieved using encrypted_extensions? Does it mean that the records which contains handshake messages are encrypted/protected from the point of ...
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1answer
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What's dh-composite test on badssl.com?

The site badssl.com provides examples of bad (red icon) and good (green icon) uses of TLS for the purpose of testing TLS implementations. I'm a bit confused by the test called dh-composite. This ...
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Best choice out of these six TLS cipher suites

I have a small embedded platform that supports 6 TLS ciphers. Is there a good/better/best one to chose? I was looking around on the web for some kind of rating system or list of ciphers that have ...
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1answer
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Any case that can require to encrypt a certificate revocation list before distribution

As far as we know certificate revocation lists (CRLs) include public information so they do not have to be encrypted before distribution. Is there a case that can require to encrypt it before ...
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DIY message level security?

This might be in danger of being too elementary a question for this community but I'm hoping for expert help: Assuming that TLS is not enough to protect messages transmitted between a client and a ...
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1answer
118 views

Insecure third party connection

My organization processes some PII data and shares it with an outbound connection (outflow only) that is a third party. The data transfer transactions occur without human intervention. That outbound ...
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DTLS 1.2 Finished message

I am implementing DTLS 1.2 and using ECDHE_RSA_AES_128_GCM_SHA256 cipher suit. Below is my client finished message Can anyone explain this message? How many bytes for verify data? Is there ...
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Which encryption is recommended for own messenger [closed]

I wrote my own messaging-app and now I would like to encrypt the data transfer between my client (app) and my server. What kind of encryption is easy to implement and can be recommended? I am very ...
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What is the current encryption method used on GSM currently?

I am currently doing a mini project which sniffs GSM packets using gr-gsm and wireshark. I was wondering if anyone knows what is the name of the current encryption algorithm method used on GSM?
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Are there any practical ways to transfer random data securely?

The owner of the random.org service recommends that you do not use randomly generated numbers from their website in cryptographic keys. This makes sense, but it got me wondering. Is it possible to ...
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What is the most secure ECC Curve?

I have for a while used Koblitz curve (sect571k1), in ECDH and ECDSA. But I have started wonder if it is the most secure. I prefer security over efficiency. So the curve doesn't have to be the most ...
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Why is SSL/TLS so complicated? [closed]

I'm new to SSL/TLS and I'm staring as a new security researcher. It appears to me that SSL/TLS protocol is needlessly complex for arriving at a shared secret. The complexity results in so many bugs (e....
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What communications security protocols exist that aren't based on PKC?

Lets say that you have two devices that need to communicate in a secure manner. These devices can share secrets before communication takes place (This sharing of secrets occurs over another secure ...
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Initializing PGP keys by one side

I am using a PGP method to encrypt and decrypt messages shared between users A and B. Upon the start of a message exchange is the initialization of the public and secret keys by both Users. Lets say ...
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Do ECDH and ECDSA combined solution provide an authenticated protocol exchange solution in MCU environment?

I'm working on a project in MCU (micro controller) environment with GPRS connection to exchange data securely with the cloud. The encryption algorithm has been selected to use AES. I did some search ...
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Secure Channel - Encryption and Decryption Keys For A Message

I'm currently reading Cryptography Engineering and in Chapter 7, the topic of secure channel is discussed. The channel described is using CTR for encryption. Below I include images with pseudo-code ...
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Shamir's secret sharing scheme - type of channels

For information theoretic security in Shamir's [m,m] secret sharing scheme, do i need both authentic and confidential channels? Another related query is ;is it true that if the channels are only ...
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1answer
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Secure Broadcast Channel

I've read a paper that says that one of the "assumptions" that it makes is secure broadcast. Why is this an assumption? Can't a broadcast channel be built with simple primitives--i.e. encrypt and sign ...
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Creating a secure key

Imagine that your lecturer and the undergraduate office have conducted a key exchange protocol after which both of them hold the string $X$. Yet, it is possible that a curious student sitting next to ...
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What is the “shared secret” used for in IPSec VPN?

Can somebody explain what the "shared secret" and "password" do when opening/creating a VPN tunnel? In this specific case I setup a VPN to my Fritz!Box and I had to provide a shared secret (which was ...
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Security of CFB on a public channel

Given a server that broadcasts all received data to all connected peers (except the sender), two participants can have an encrypted conversation using a self-synchronizing method like CFB and some ...
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Secure communication between multiple peers on a public channel

I am wondering how can I secure communications between multiple peers over a public channel, like an IRC channel. With two peers it is easy - they exchange their encryption keys and decrypt the ...