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.
15
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4answers
5k views
Google is using RC4, but isn't RC4 considered unsafe?
Why is Google using RC4 for their HTTPS/SSL?
$ openssl s_client -connect www.google.com:443 | grep "Cipher is"
New, TLSv1/SSLv3, Cipher is RC4-SHA
Isn't RC4 ...
15
votes
7answers
1k views
How can SSL secure a two-way communication with only one key-pair?
As I understand it, SSL involved the use of a public-private key pair. How does this enable two-way communication?
Suppose I have some server with which I wish to communicate securely. I connect to ...
14
votes
2answers
648 views
Is HTTPS secure if someone snoops the initial handshake?
Let's say I'm on an open wireless network that's being actively sniffed and I connect to an HTTPS site. Even though my subsequent traffic is encrypted, couldn't the sniffer use the data from the ...
9
votes
2answers
252 views
Is RC4 a problem for password-based authentication?
This is a follow-up question to Does TLS use RC4-drop[n]?.
As mentioned in section 6 of RFC4345, there are weak distinguishers for RC4 keystreams available that even work for keystreams that ...
8
votes
2answers
2k views
How can Cipher Block Chaining (CBC) in SSL be attacked?
I am trying to understand how CBC-mode in SSL/TLS can be attacked.
I have been looking around online but all examples and explanations are very hard to understand and follow. Can you give a simple ...
6
votes
5answers
2k views
Why do we need asymmetric algorithms for key exchange?
In SSL protocols, both symmetric and asymmetric algorithms are used. Why is it so? The symmetric algorithms are more secure and easier to implement. Why are asymmetric algorithms usually preferred in ...
6
votes
1answer
381 views
What causes first block of AES decryption to be garbled, even with correct IV?
I am attempting to duplicate wireshark's packet capture decryption for a TLS HTTP session, where I control the private key of the server.
The cipher suite number is 0x00002f, TLS_RSA_AES_128_CBC_SHA
...
5
votes
2answers
208 views
Does a trace of SSL packets provide a proof of data authenticity?
I'm wondering if it would make sense to record a whole HTTPS session,
publish its encryption keys and present it to third parties as a proof
that this particular data was sent by a given server ...
5
votes
1answer
491 views
Why is CAMELLIA suddenly so widely used?
When nowadays I point my browser to https sites, the cipher that is on most occasions used is Camellia. My browsers (Chrome and Firefox) seem to prefer it, even when AES is available.
Is that not ...
5
votes
1answer
201 views
Does TLS use RC4-drop[n]?
According to many sources, the first few (n) bytes of the RC4 keystream are strongly biased, and therefore should be discarded before using the keystream to encrypt anything; this precaution is ...
5
votes
1answer
98 views
Using encryption schemes for identification
I've been researching how to implement a post-quantum SSL-like connection authentication, especially correct identification&authentization of the server/client. Because good post-quantum digital ...
4
votes
2answers
190 views
Is SSL getting faster because it's getting less secure?
There has been some discussion about it being more practical to use SSL due to advances in hardware. From my understanding, stronger public-key encryption means that both encrypting/decrypting and ...
4
votes
2answers
565 views
What is the purpose of four different secrets shared by client and server in SSL/TLS?
I was looking through the working of SSL V3, and found that a connection state is defined by a set of things, including
client write mac secret,
server write mac secret,
server write key,
client ...
4
votes
1answer
98 views
Client and server using same SSL certificate - any issues?
I'm working on software where multiple components will communicate with each other using SSL.
There would be one central component acting as a server, which would also require the clients to present ...
4
votes
1answer
127 views
How common are SEED certificates outside of Korea? When is support required?
I'm looking at the SEED algorithm and would like to know if this is still in common usage.
Can anyone tell me when I would need to implement this standard, either as a client or a server?
3
votes
2answers
7k views
How secure is AES-256?
The cipher AES-256 is used among other places in TSL/SSL across the Internet. It's considered among the top ciphers.
In theory it's not crackable since the combinations of keys are massive.
Although ...
3
votes
3answers
269 views
Does the XML Encryption flaw affect SSL/TLS?
A "practical attack against XML's cipher block chaining (CBC) mode" has been demonstrated:
XML Encryption Flaw Leaves Web Services Vulnerable.
Does this weakness of CBC-mode which is used here also ...
3
votes
2answers
574 views
How key materials are generated in SSL V3 from master secret
The generation of key materials is given by
...
3
votes
2answers
79 views
What are the potential security impacts of using CRAM-MD5 for Emails, when not using an SSL connection?
Background: My current server-provider tells me it's no problem to store the passwords in plain-text in the database, saying he has to do so because they use CRAM-MD5 for email authentication. But ...
3
votes
1answer
110 views
SSL Key Exchange
I read briefly over the TSL/SSL key exchange protocol. I have to wonder about the whole pre-master-key procedure. Wouldn't it be sufficient if the client or server encrypted a generated session key ...
3
votes
1answer
213 views
is this RSA private key valid?
is this RSA private key valid?
First, here's the RSA private key in question:
...
3
votes
1answer
654 views
What is the 'Version Incompatibility" Problem in TLS 1.1/1.2 and 1.0?
It's unclear to me if there are multiple problems, or a single one, (and just what that problem is) with servers incorrectly negotiating down from a client offering 1.1 or 1.2 to something they ...
3
votes
1answer
148 views
Is there a field guide to ECC for the IT Security layman?
I'm trying to understand ECC from an IT layman's perspective and am trying to separate the theory from the standards, and understand why certain features are implemented or not implemented in the ...
3
votes
0answers
216 views
Why do new versions of TLS use an explicit IV for CBC suites?
SSL 3.0 and TLS 1.0 used an insecure scheme to generate implicit IVs when encrypting records in CBC mode: They used the last part of the previous record, a value that can be predicted by the attacker. ...
2
votes
2answers
146 views
Protocol to generate Client Certificates at the start of a SSL session automatically?
A more secure form of 'cookie' could be created for SSL communications through the following method.
The client generates and requests the server to sign a certificate.
Then the client authenticates ...
2
votes
2answers
126 views
The security of data traffic over both SSTP & SSL
Suppose you're connected to a VPN server via an SSTP VPN, and then you're trying to sign in to your webmail account that is already secured with an SSL certificate, e.g. hushmail.com.
However, it ...
2
votes
2answers
415 views
Are there standards for transport layer security using only symmetric keys?
I have an embedded system with AES-128 implemented in hardware. There is very little flash/RAM and the (8-bit) CPU runs relatively slowly. Public key crypto isn't a viable option. This system is ...
2
votes
1answer
287 views
Poor man's SSL - is this method as safe as SSL/TLS?
I need to send data between two applications. I've got requirement that says that data should be transmitted using secure protocol such as SSL/TLS. Data is sent using TCP sockets and I don't have ...
2
votes
1answer
366 views
What does SSL use? RSA? El-Gamal? Elliptic curves?
I'm not sure what SSL uses to share the symmetric key to both end users, i.e. at the beginning of the communication. Is it RSA? Or El-Gamal? Or something else?
Thanks!
2
votes
2answers
804 views
How to distribute session keys in public key cryptography?
In public key cryptography we can also use session keys which are symmetric. How do the sender (say a server) provides this session key information to its clients?
If the sender (here server) ...
2
votes
2answers
111 views
Generating IV in TLS 1.2
I'm writing a TLS 1.2 implementation (in C#) using a custom protocol.
My question is how to generate the IV attached to each message, I don't want to use RandonNumberGenerator because I've heard it ...
2
votes
1answer
57 views
Separate Read and Write Keys in TLS Key Material
Why does the TLS protocol use different symmetric keys for receiving and sending data?
Isn't it enough to have a single key used for both reading and writing?
2
votes
3answers
1k views
Which one of the Block Cipher modes is the best?
I have two questions regarding the Block Cipher Modes:
First: Which one of the modes is considered the best?
I know CBC has a problem of IV since the next block of the plain text is XORed with the ...
2
votes
1answer
92 views
is it possible to spoof an identity cert modulus
I was looking at foaf+ssl http://www.w3.org/wiki/Foaf+ssl and wondering if its possible to spoof the modulus of the browser cert so that the foaf and browser cert modulus match
2
votes
1answer
306 views
Is there a standard for OpenSSL-interoperable AES encryption?
Many AES-encrypted things (files, strings, database entries, etc.) start with "Salted__" ("U2FsdGVkX1" in base64).
I hear it's some sort of OpenSSL interoperability thing a b c.
Is there some ...
2
votes
1answer
78 views
Educational videos for security topics [closed]
Is there anything like the famous "sorting out sorting" video in cryptography/security.
I am looking for some nice videos that explaines SSL, SET, IPSec, PGP, S/MIME ....
1
vote
3answers
222 views
Would this simple encrypted chat program be feasible using One Time Pads?
Lets say I want to build a simple chat program that has encryption that is impossible to crack for anyone, even a theoretical government with a massive super computer. Ok here's my idea. You'll need ...
1
vote
2answers
214 views
Is Common Name encoded in the certificate?
When I make a certificate like so
cd /etc/openvpn/easy-rsa/2.0/
source ./vars
. /etc/openvpn/easy-rsa/2.0/build-key client1
Then ...
0
votes
1answer
236 views
SSTP MSCHAP-V2 Authentication before SSL or after SSL Session
So with the recent news that there's a lovely new tool to crack MSChapV2 packets.
So the question I have is on a SSTP Connection is the MSChapv2 handshake encrypted pre SSL setup or post. Obviously ...
0
votes
1answer
157 views
How does a client verify a server certificate?
As far as I know,
when I request a certificate from Verisign (for example), and after they approved that me is me, they create a certificate (for me) which contains the digital signature and public ...
0
votes
0answers
27 views
Decrypting TLS in Wireshark when using DHE_RSA ciphersuites [migrated]
How can I decrypt TLS messages when an ephemeral Diffie-Hellman ciphersuite is used? I am able to expose the premaster secret and master secret from the SSL Client. Using that, how to decrypt the ...
0
votes
0answers
154 views
Cryptographic Protocol using NaCL
Why?
I wanted to add some security and privacy to a chat-type server for playing various games (with a few things that are done on the server to limit cheating). Going by the "Don't implement ...
-2
votes
0answers
33 views
Decrypting the Encrypted hex applcation data with encryption keys [closed]
I am having all the keys,
...
