Key exchange protocols

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1answer
697 views

How do I share my S/MIME public key?

I have setup S/MIME encryption for my email address, and I'd like to allow people to download the public key from my website, rather than having to first receive an email from me. I want the public ...
2
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2answers
188 views

Key distribution and key exchange for simple secure FTP implementation

I'm developing a simple secure file transfer protocol for a University project using openssl. I have a Client (let be C) and a Server (let be S). C will send to S messages like get, put, cd, … and S ...
2
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3answers
65 views

Is it a good practice to include a download URL of my GPG public key in my email signature?

I was wondering if I can put a download URL for my recipients to get my GPG public key easily in my email signature. Is this a good practice? If not, what's a good alternative?
2
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1answer
98 views

Picking exponents for Diffie-Hellman

I'm taking a class on Cryptography and the professor mentioned that given mod N and base g with a certain order, you should pick powers m and n such that they create a certain property with the order ...
2
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0answers
363 views

How to secure API (private key) for mobile apps

I am building a web service that has to be only accessible for iOS apps. In the future I want to expand to a mobile website to make my service also available for other mobile operating systems. Now, ...
2
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0answers
58 views

Main difference between Yahalom and Needham-Schroeder key exchange protocols

I am just wondering what is the main difference between the Yahalom and Needham-Schroeder key exchange protocols? Which protocol uses less computational power?
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3answers
158 views

Cryptography key gathering tool

I am wondering if there exist a tools which can return the value of the one of the private key if the following are known: 1) Encryption Algorithm 2) Public key 3) Plain text 4) Cipher text Or may be ...
1
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1answer
128 views

Is there a known vetted alternative to this key-exchange protocol?

I have three participants: A client A in possession of the public key Kpub A login server S in possession of the private key Kpriv Game servers B (B1, B2 etc) S and all B may share a finite number ...
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2answers
72 views

SSL/TLS : Authentication mechanism

I have these doubts regarding authentication in SSL/TLS : Will there be an authentication involved for all SSL connections ? For eg. when I browse the internet, using the most up-to-date browser, ...
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1answer
492 views

ECC Brainpool Standard Curves and Curve Generation with Bouncy Castle which seed to use?

I want to implement a ECC Key Agreement with a Brainpool curve brainpoolP512r1 or brainpoolP512t1. I'm not clear about whichseed value to use (and how). In this document ...
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1answer
61 views

GSM A5/1 encryption: Key management

I'm currently studying the A5/1 algorithm used for GSM encryption. I understood how thanks to the symmetric private Key and a public counter frame one can encrypt the communication between A and B. ...
1
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1answer
267 views

Can manual hash verification defend against a DH MITM attack?

I understand how DH key exchange is vulnerable to a MITM attack. When Alice sends Bob g, p and her public key, if she also sent a value H that was a hashing of the values g,p, and public key all ...
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2answers
101 views

How to treat/hash ECDH shared secret to use as keys for AES?

I'm doing some studies/development for a security system that would use ECDH with ephemeral keys. In my code I'm currently using a 256-bit EC, so when the two parts compute the shared secret, I get a ...
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0answers
60 views

Does Diffie-Hellmann (DH) key exchange protocol lower Off-The-Record protocol (OTR) security level?

Off-the-Record protocol employes Diffie-Hellman key exchange protocol (DH). DH protocol does not provide authentication of the communicating parties and, according to many sources, is vulnerable to ...
1
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0answers
47 views

Any Suggestion Exchanging shared key between process via port in untrusted machine (infected my malware)?

I am trying to get shared key between Firefox extension and a java program running in same machine. I am communicating both application via socket. My assumption is that malware is running in ...
1
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1answer
2k views

The request was aborted: Could not create SSL/TLS secure channel Exception

Let me explain my situation. I created a self-signed certificate and installed it in the Trusted Root Certification Authorities section in MMC. I then created two certificates using the self-signed ...
1
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1answer
163 views

Secure Encrypted Chat Protocol [duplicate]

Possible Duplicate: Is there a way to negotiate a secret between 2 parties with no prior knowledge? Imagine two clients who want to establish a secure connection over a server. Both clients ...
1
vote
1answer
74 views

Is a Diffie Hellman Ephemeral key good material for being used as a symmetric cipher algorithm key?

I am designing a secure protocol (for academic/learning purposes) and I am at the point where I need to (re)design the key exchange step. In my previous implementation, I used to rely on RSA to ...
0
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3answers
847 views

Are there flaws in this simple key exchange?

I'm reviewing for a computer security exam. Here is a simple scenario: Suppose that someone suggests the following way to confirm that the two of you are both in possession of the same secret key. ...
0
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2answers
633 views

Diffie-Hellman key-exchange: securing prime and base

As we know DH algorithm based upon 2 large prime numbers, which are used to be called as prime and base I am writing app which implements DH key exchange algorithm. From security point of view should ...
0
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2answers
70 views

does a public key work with all encrypted programs

let us say, I use program "x" for my e-mail security. through them I have a public key and a private key. My friend uses program "y" for their e-mail security and consequentially have a public key ...
0
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1answer
63 views

Purpose of key confirmation

Among the requirements for a secure key exchange is the key confirmation. I wonder why is this step required. Even if the other party hasn't computed a correct value for the shared secret, it doesn't ...
0
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1answer
29 views

Evaluation of cryptosystem for authentication and keyexchange

I'm a masters student in computer science who works part time with my own company as a consultant. My lastest project is based on my bachelor thesis which handles everything except the security. The ...
0
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1answer
83 views

Which is better in “DH-group14-sha1 with hmac-sha2-256” and “DH-group-exchange-sha256 with hmac-sha2-256” from performance and security perspective?

In our product (embedded system), so far we were using diffie-hellman-group1-sha1 with hmac-sha1. But due to security concern we are planning to use diffie-hellman-group14 for key exchange and ...
0
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1answer
54 views

Key-Exchange Algorithms VS Local Key Generation?

I was wondering the difference in term of Security, Computational cost and Network overhead between the use of : A Key-Exchange Algorithm (e.g. Diffie–Hellman) to set up a symmetric key. The ...
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1answer
68 views

Key Exchange algorithm to be used for REST framework

I was required to create key exchange module for custom Rest framework which supports document level security in REST requests. Framework has its own security module which allows to encrypt parameter ...
0
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3answers
133 views

What are the MitM implications of a stolen client-side private key?

Many VoIP handsets support client-side SSL authentication for auto-provisioning. Unfortunately, some devices must be programmed with their client-side keys. (Keys generated on low-entropy devices are ...
0
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1answer
563 views

Why Qualys SSL Server Test is giving me 80 and not 100 in Key Exchange?

My openssl ciphers -v 'CIPHER' output is the following: ECDHE-ECDSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=ECDSA Enc=AESGCM(256) Mac=AEAD ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=RSA ...
0
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2answers
138 views

How do key servers resolve conflicts?

According to the PGP network FAQ While a number of key servers exist, it is only necessary to send your key to one of them. The key server will take care of the job of sending your key to all ...
0
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1answer
30 views

Is the Station-to-Station protocol secure?

After I've read a lot about key exchange many sources state that the Station-to-Station is secure, since it also verifies the entity on the other side. Well how is that true, if an active Man in the ...
-1
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1answer
553 views

GPG advantages / disadvantages, is it useful or secure? [closed]

I thinking about GPG, is very widely used, but is secure? Why and where we using GPG? I found an article from 2002, but is very old.
-1
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1answer
159 views

Theorical question on encryption methods [duplicate]

Possible Duplicate: Encryption strategies for multi users access in production systems I would like to develop a service on wich clients would connect and retrieve informations. These ...
-2
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2answers
120 views

Understanding a key establishment protocol

I'm studying a one-pass key establishment protocol. Let be A client and B the Server. A sends to B: E_w(t,b,k) where t is a timestamp requested for freshness, k is the ephemeral key that will be ...