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Questions tagged [tls]

SSL (Secure Sockets Layer) and its successor TLS (Transport Layer Security) are protocols which provide communication security (privacy and integrity) for a bidirectional data channel.

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52 views

How to encrypt data when send over https

I know its not practical to encrypt data when you send over https for widespread consumer use. But if i had to, how would i do that?. One way is for the server and client to agree upon an additional ...
2
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1answer
32 views

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 ...
8
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1answer
251 views

Which TLS features are vulnerable to chosen-prefixes collision on SHA-1?

Gaëtan Leurent and Thomas Peyrin's preprint From Collisions to Chosen-Prefix Collisions - Application to Full SHA-1 (in volume 1 of proceedings of the forthcoming Eurocrypt 2019) shows a feasible ...
6
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2answers
2k views

Why is PerfectForwardSecrecy considered OK, when it has same defects as salt-less password hashing?

PFS suites suffer from the same defects as any other salt-less password hashing scheme. Why is everyone promoting Perfect Forward Secrecy (PFS) ciphersuites so fiercely? Namely, when the group/hash ...
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0answers
19 views

Which parts of a TLS connection can I safely reuse for DTLS to the same peer?

Suppose I need both encrypted TCP and UDP, say TCP for reliable control signals from server to client and UDP for low latency data from client to server. If I first establish TLS, for the DTLS ...
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0answers
20 views

Identify uniquely a SSL certificate [migrated]

I want to know how can I find out make for sure that a given file is an SSL certificate and not other thing. Is the file extension is enough to find out that a file is a certificate or not?
3
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1answer
178 views

How will be cipher selected when client is running on version TLS 1.3 and server is running on TLS 1.2?

How will be cipher selected when a client is running on version TLS 1.3 and server is running on TLS 1.2? The cipher list provided by TLS 1.3 client will be different than the version supported on ...
2
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1answer
67 views

What key is used to encrypt the certificate and certificate verify message in TLS1.3?

Which key is used to encrypt certificate and certificate verify message in TLS1.3? I could not figure out which one it is reading section 4.4.2 of RFC 8846 and I only saw a vague mention on page 11.
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1answer
44 views

What SALT value will be used in HKDF_EXTRACT in TLS1.3?

What SALT value will be used in HKDF_EXTRACT while generating the Handshake Secret (when there will not be any PSK)?
1
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1answer
60 views

When do clients use TLS in PSK mode?

The TLS protocol can perform the handshake in different modes. Either fresh handshake where new keys are generated, or using Pre Shared Keys (PSK) or what was know as Session Resumption in previous ...
3
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2answers
136 views

Which hash is used when providing signature algorithm ED25519 or ED448?

From TLS 1.3 there are two signature algorithms using edDSA: /* EdDSA algorithms */ ed25519(0x0807), ed448(0x0808), All the other signature-...
3
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1answer
172 views

Why Static RSA and Diffie-Hellman cipher suites have been removed in TLS 1.3?

Why Static RSA and Diffie-Hellman cipher suites have been removed in TLS 1.3? How keys can be exchanged then? https://tools.ietf.org/html/draft-ietf-tls-tls13-28
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96 views

Which 'info' and 'salt' parameters to use in HKDF for TLS 1.3?

all the following discussion is for HKDF in TLS1.3: Regarding the 'salt' parameter in - HKDF-Extract(salt, IKM) as written in RFC 5869: HKDF without having to protect the secrecy of the salt. In ...
0
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1answer
158 views

Is LibreSSL affected? - Downgrade Attack on TLS 1.3

https://news.ycombinator.com/item?id=19111707 https://www.nccgroup.trust/us/about-us/newsroom-and-events/blog/2019/february/downgrade-attack-on-tls-1.3-and-vulnerabilities-in-major-tls-libraries/ No ...
2
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1answer
173 views

TLS 1.3 Secure Renegotiation not supported [closed]

I get the message "Secure Renegotiation IS NOT supported" if a TLS 1.3 cipher will be chosen at a TLS handshake with openssl s_client. Since TLS 1.3 does not support renegotiation at all I assume that ...
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0answers
45 views

Understanding TLS certificate

I'm newbie in the word of TLS, and need some verification about my picture. I can use TLS with 3 or 2 participants: 3 participants: Client, server, CA (certification authority). The CA is where the ...
0
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1answer
95 views

Public key on Server Key Exchange Generation vs Public key on Server's Certificate

To understand the distinction between TLS 1.2 and TLS 1.3. I am stuck in the past understanding for TLS and the current reference I am studying: As I know certificate goes with owner's public key, ...
1
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1answer
157 views

Can a TLS certificate using ECC secp384r1 as PK algorithm uses RSA for signature

If a TLS certificate public-key algorithm is ECC secp384r1 or ECC prime256v1, is it possible to have RSA as a signature ...
0
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1answer
142 views

Does RSASSAPSS use RSA signature

I just need to know is it correct to classify the RSASSAPSS scheme and sha[256 | 512 | 1]WithRSAEncryption all under RSA ...
4
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2answers
255 views

GMAC vs HMAC in message forgery and bandwidth

Saarinen in his work GCM, GHASH and Weak Keys says that; The GHASH algorithm belongs to a widely studied class of Wegman-Carter polynomial universal hashes. The security bounds known (this and ...
4
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0answers
63 views

Can “OPAQUE-over-TLS” authentication be optimized?

So while discussing the issues of password-hashing off-loading in our chat I noticed that it's easy to extend OPAQUE (CFRG draft) to essentially be a better standard password based authentication when ...
3
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1answer
355 views

SSL - encrypt with private key and then with public key?

Say there are 2 sides that wish to communicate: side A and side B. Let's say we are looking at side ...
8
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1answer
509 views

The 9 lives of Bleichenbacher's CAT, it puts another scratch again

Bleichenbacher demonstrated a padding oracle attack against RSA implementations that follow the PKCS #1 v1.5. Through the years, there are various mitigation techniques developed as OAEP and limiting ...
0
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1answer
152 views

Does make sense utilize TLS and Noise Protocol in the same application?

Nowadays I work maintaining an web application written in Node.js and we use HTTPS with TLS 1.2. We have to implement a new feature related to security on this application, all HTTP messages must be ...
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1answer
57 views

What can eve see when I go to https//paypal.com

If I go to https://paypal.com/ and login, can Eve find the approximate size of the HTTPS request from my browser? Can she see the approximate size of the responses from the paypal server to me? and ...
11
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1answer
173 views

How does the process of creating a new secure Elliptic Curve look like?

I'm especially curious about the technique djb would have used to come up with his Curve 25519. Say I have already written down my goals, such as - Twist Secure, Speed, Side Channel resistance, etc. ...
2
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1answer
74 views

Why don't the TLS1.3 cipher suites mention the key exchange and digital signature algorithm in names?

Does it mean both RSA and ECDSA certificates can be used with the same cipher suite?
0
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1answer
36 views

When a program using openssl library is using a certificate, does the server check if the issuer(s) are still valid

If I have a program acting as TLS server with a certificate signed by a CA, if one of the issuers in the chain becomes invalidated or the date expires, then how does the program using the certificate ...
2
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0answers
152 views

Sharing RSA private key between SSH and SSL services. How bad is it?

An appliance uses a curious way of obtaining ssh-rsa host keys: There is a single configuration option "management certificate" that sets RSA private keys both for HTTPS and SSH management. ...
3
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1answer
137 views

In a TLS 1.3 connection, how do the client and server choose a mutual cipher suite?

According to KeyCDN, TLSv1.3 connections are established in a single round trip: While TLS 1.2 requires two round-trips to complete the TLS handshake, 1.3 gets the job done in just one trip If ...
26
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2answers
2k views

Why did TLS 1.3 prohibit PGP authentication?

There is a specification, in Informational(!) RFC 6091, for using PGP keys in TLS authentication, although I don’t think it has ever been implemented outside of GnuTLS (it’s certainly not in OpenSSL). ...
2
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1answer
31 views

Are Authenticated Encryption ciphersuites supported in legacy TLS versions older than TLS 1.2?

I have read in a paper that Authenticated Encryption (by this I mean those that support GCM mode or ChaCha20 ciphers) are not supported in versions older than TLS 1.2? I could not confirm this as ...
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2answers
918 views

Why does curl need both root and intermediate certificates in order to securely connect to an HTTP server?

I have created a root certificate, an intermediate certificate, and a server certificate: ...
10
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1answer
343 views

Why does TLS 1.3 support two CCM variants?

One of the important improvements introduced in TLS 1.3 is the pruning of the many previously available cipher suites to only five secure options (for symmetric ciphers), that are each supposed to ...
6
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1answer
269 views

Cipher suites: same name, different IDs, why?

Sorry if I missed with a community to ask. Recently I stumbled on a fact that the same cipher suite can be designated by two different IDs, and this is not a typo nor single occasion. For instance: ...
2
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2answers
526 views

The attacker model of the Lucky13 attack in TLS

Lucky13 is a timing attack against the MAC in the CBC MAC-then-encrypt ciphersuites. In the attack's page: The attacks involve detecting small differences in the time at which TLS error messages ...
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4answers
61 views

TLS ciphersuite without mode of operation

Will there be any security concern if there is no mode of operation specified in the ciphersuite name? For instance, there is no mode of operation in ...
3
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4answers
346 views

JWT Login Security

I am new to security and I am wondering if JWT is secure enough. From what I have read online the flow goes like this: Clients log in by sending their credentials to the identity provider. The ...
1
vote
1answer
329 views

CBC related TLS cipher suites to be disabled in the server side

I understand the TLS cipher suites using CBC mode are susceptible to timing attacks. From that understanding it seems that the cipher suites using GCM (CTR-based) are safe to use considering they don'...
2
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2answers
99 views

Does the Server Key Exchange sign a hash or text

In TLS 1.2 when using ECDHE_RSA, the ServerKeyExchange message contains a signature over the server's ECDHE public parameters. My question is: Is the signature over ...
1
vote
1answer
126 views

How Elliptic-Curve affects the Server Key Exchange parameters

In Finite Field DHE, the server sends the following parameters in the server key exchange message: $p$: prime $g$: group $g^b$: the server's public DH key In DHE_RSA (non anonymous DHE), the server ...
0
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1answer
57 views

When using Client Certificates, is it usual to generate your own?

We're building a webservice for a third party customer who wants us to use "two-way SSL". By which I understand them to mean they want us to host the site using https, and to require that include a ...
3
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3answers
994 views

What is different below two Ciphersuites?

I have two questions; I need an explanation for the differences of below two cipher suites. How do they work with SSL/TLS protocol? (my main concern first one doesn't have '...
1
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2answers
312 views

signature with Bleichenbacher’s attack

I understood Bleichenbacher & ROBOTO attack, however I have some trouble understanding Section 3.5 of ROBOT attack which discusses retrieving private keys. https://www.usenix.org/system/files/...
1
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1answer
226 views

Cipher Block Chaining (CBC) encryption in SSL

Is cipher block chaining (CBC) mode used in SSL encryption? If block reordering is already protected by SSL and TCP sequence numbers, what added advantage does CBC provide?
0
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1answer
78 views

How is the TLS 1.2 sequence number generated?

In the other ciphers supported by TLS 1.2, namely stream cipher and CBC block cipher mode, the sequence number is implicitly in the MAC (RFC5246, 6.2.3.1): ...
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1answer
187 views

Tls protocols: is the simple diffie hellman key exchange still used these days?

Or did it mostly get replaced by ecdh for key exchange and rsa for authentication ?
2
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1answer
68 views

Does DROWN attack break 2048-bit key itself or just the plaintext encrypted with the RSA key

Does the DROWN attack enable breaking strong RSA keys (e.g. the 2048-bit key itself) or enable breaking the plaintext (i.e. pre-master key) that is encrypted with a 2048-bit (or any strong) RSA, if ...
2
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0answers
41 views

Is my way safe to remove SSL CA Cert by DHT and PoW NodeID for a decentralized system?

To implement a decentralized system, I wrote a TLS like P2P net stack. The main idea is removing CA Cert from the whole system by using a DHT for Naming and Key Exchange. I am not a crypto expert, so ...
0
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1answer
189 views

How does OpenVPN work?

I'm confused with the technologies that OpenVPN uses. The official site mentions it uses SSL/TLS in-place of IKEv1/IKEv2, and uses IPSec ESP to secure the data, and yet that it isn't compatible with ...