All Questions
Tagged with transport-security key-exchange
11 questions
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Is ECDH still secure if I embed the server public key?
I'm pretty new to the concept of key exchange.
Diffie-Hellman does not have authentication, so it makes no guarantees on who is the other party of the connection.
Both key pairs (client/server) need ...
- 103
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29
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Signal's X3DH Protocol - what is Alice's ephemeral key? Is the previous ephemeral key used in the next message's run? Are one-time prekeys signed?
In the Signal Protocol and X3DH Protocol:
https://signal.org/docs/specifications/x3dh/
I have a few questions:
1. In section 3.3. "Sending the initial message", it says:
Alice verifies the ...
1
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1
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51
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Security of keys that are as long as the data
If both communicating sides end up with the same secret 3000-bit key, is it enough to XOR each byte of the messages with each byte of the secret key to make it secure?
Wikipedia says it is, but I ...
- 159
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Securely transmit signed token (e.g., JWT) over insecure channel
Apologies if this is already answered somewhere, but I could not find it.
I have a setup where a client has a JWT (RSA- or ECDSA-signed), and needs to prove that fact to the peer which issued the ...
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98
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Interactive ECDHE Authentication With Numeric Code
Trying to simplify my question, keeping only core concepts.
Proposed solution:
Both user devices generates ECDHE key pairs. Send pub keys to each other. Generate shared secret.
Device that requests ...
2
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1
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154
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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 ...
- 123
3
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1
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641
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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 ...
- 133
3
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1
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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):
...
- 159
5
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2
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3k
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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. ...
- 159
2
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0
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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 ...
- 121
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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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