Tagged Questions
1
vote
1answer
70 views
SSL Communication and Proxy
Let us say that I have a client and a server communicating using SSL.
If a hacker sets up a proxy between the client and the server, will he be able to decrypt the data which is being sent?
4
votes
3answers
99 views
What SSL options should not be used?
What SSL options should be avoided, due to recently discovered weaknesses? This might include symmetric algorithms, or MAC functions.
3
votes
4answers
264 views
Can an attacker reuse stolen SSL private key to recreate that domain on his server
Say my domain (https://example.com) SSL private key has been stolen and was not protected by a passphrase then.
Can the attacker uses that key and certificate to host the same
domain on different ...
0
votes
1answer
118 views
Is TLS secure when full eavesdropping on the network occurs? [duplicate]
Possible Duplicate:
How is it possible that people observing an HTTPS connection being established wouldn’t know how to decrypt it?
Alice connects to Bob's site via a TLS secured connection ...
1
vote
2answers
458 views
KDC(Key Distribution Center) vs Asymmetric Key Exchange
Today I was reading notes about cryptography and I came across a problem that exists in Symmetric Key encryption, which is how to share the secret key across the network.
1st Method :
Make use of ...
5
votes
1answer
182 views
Most efficient key algorithm for a TLS server key?
Let's assume I want to setup a HTTPS service on a modern-but-no-so-speedy x86 server without any form of hardware cryptographic accelerator.
Which key algorithm should I choose for the server key in ...
8
votes
2answers
601 views
Are there really functioning quantum computers?
I saw this video on youtube on quantum computing. It says that a company called dwavesys has already made commercially available quantum computer. I checked on the website and it exists. I thought ...
6
votes
2answers
189 views
Is HTTP compression safe?
The CRIME attack taught us that using compression can endanger confidentiality. In particular, it is dangerous to concatenate attacker-supplied data with sensitive secret data and then compress and ...
3
votes
1answer
61 views
CMC (RFC 5272) compatible CA server
I need a CA server or any tool that supports Certificate Management over CMS (CMC) format, described in RFC 5272 (RFC 2797). I need a possibility to generate different Full PKI requests and responses ...
3
votes
1answer
68 views
SSL Based Denial of Services due to Message Digest
On a very high level, its known that SSL/TLS uses message digests to verify the integrity of the messages sent.
However, the question I have in mind is :
How does SSL ensure a DoS does not happen ...
6
votes
3answers
307 views
How secure is HTTPS with weak ciphersuites?
Today I came across the website https://mtgox.com/, which claimed to be secure because of the Verisign certificate. I checked the certificate out of curiosity (it's the first thing they claim, let's ...
5
votes
3answers
972 views
HTTP Basic auth password storage more secure than Digest auth
If you are using SSL already, it appears Basic auth is the way to go since you can perform bcrypt with the password when you store it in the database, where as Digest auth only allows md5. As we know, ...
1
vote
1answer
602 views
What are the consequences of disabling ssl v2 and weak ciphers?
It is my understanding that IIS has ssl v2 enabled by default. Also, TLS 1.0, if enabled, allows for at least one known major vulnerability titled "beast attack".
If the weak and vulnerable ciphers ...
6
votes
1answer
2k views
What is the actual value of a certificate fingerprint?
In a x509 digital certificate there is a "certificate fingerprint" section. It contains md5, sha1 and sha256. How are these obtained, and during the SSL connection, how are these values checked for?
4
votes
4answers
321 views
Does a CA need to have the same type of key as the certificates it is signing? RSA / Elliptic Curve (EC/ECDH/ECDSA)
I am making a CA that I hope to be able to sign RSA and Elliptic Curve-capable (EC) keys with. I was wondering if the best approach was:
CA with RSA keys capable of signing RSA and EC CSRs
CA with ...
3
votes
3answers
244 views
TLS Renegotiation Indication Extension vulnerability
I am trying to understand the TLS Renegotiation Indication Extension from the RFC.
I can understand that it is related to the fact that the renegotiation is send under the encrypted stream but can not ...
3
votes
1answer
540 views
how do extended validation X.509 certs work?
https://www.forumatic.com/ uses an extended validation cert. wikipedia.org's entry on extended validation certs says that a cert is known to be an extended validation cert if the OID in the ...
1
vote
3answers
3k views
What does these warnings mean on an SSL connection by firefox (only)
I am connecting to a secure site and firefox mentions about identity:
Owner: This website does not supply ownership information
Verified by: Not specified
Technical Details:
Connection ...
2
votes
1answer
193 views
Is SSL session based only? Is there a (formal) definition of an SSL connection?
In various docs on SSL there is a mention of connection.
But from the context I am not sure if this means the underlying TCP connection or the SSL connection.
I am thinking that there is no SSL ...
2
votes
1answer
117 views
Browsers and export regs. Is SGC still valid?
I was reading a rather "dated" book on SSL/TLS, which mentions about International Step Up certificates and Microsoft's Server Gated Certificates which were the way arround the US export rules for ...
1
vote
4answers
5k views
how safe is the 256 bit encryption used in bank transactions
Most of the banks use a 128 bit or 256 bit encryption. What does this mean? Does it mean that the keys used in ssl are 128 bit long or what?
If they are the ssl key lengths then 128 bit rsa keys are ...
1
vote
1answer
85 views
valid intermediate certs not in browser
Say an X.509 cert is signed by an intermediate cert that's not in your browser. Maybe the root certificate is but not the intermediate cert. At that point it seems like a valid certification path ...
2
votes
1answer
85 views
self-signed certs that aren't the final certificates in the path
The X.509 spec makes frequent statements like this:
(b) If certificate i is self-issued and it is not the final
certificate in the path, skip this step for certificate i.
How can you have ...
7
votes
2answers
281 views
X.509 certificate policies question
I asked another question about certificate policy mappings. This is a different issue. This is about Certificate Policies.
To quote from the X.509 RFC:
In an end entity certificate, these ...
1
vote
1answer
207 views
X.509 certificate policy mapping question
So I'm a little confused how X.509 certificate policy mappings work. So let's say the following depicts my cert chain:
root CA ---> intermediary CA ---> client cert
Would the root CA have a ...
0
votes
1answer
630 views
Explanation of SSL handshake with certificate
I've read a lot of articles.
The client uses the information sent by the server to authenticate the
server. If the server cannot be authenticated, the user is warned of
the problem that an ...
3
votes
2answers
1k views
Confusing about Ephemeral Diffie-Hellman
1 Does Ephemeral Diffie-Hellman support authentication?
Quote from www.rsa.com/products/bsafe/documentation/mesuite21html/dev_guide/group_EPH_DH.html
Ephemeral Diffie-Hellman does NOT provide ...
0
votes
1answer
202 views
id-ce-cRLDistributionPoints ASN.1 / DER encoding question
I have a file - test.pem - with the following contents:
-----BEGIN CERTIFICATE-----
MBIwEKAOoAwwCqMIMAZhBEFCQ0Q=
-----END CERTIFICATE-----
openssl asn1parse -inform PEM -in test.pem -i returns the ...
0
votes
1answer
238 views
question about implicitly tags in ASN.1
From the X.509 RFC, in the "Implicitly Tagged Module" section:
CRLDistributionPoints ::= SEQUENCE SIZE (1..MAX) OF DistributionPoint
DistributionPoint ::= SEQUENCE {
distributionPoint [0] ...
3
votes
1answer
1k views
Recommended Cipher Suites for TLS 1.0, 1.1 and 1.2
There are a lot of cipher suites defined in the in the specifications itself of TLS 1.0, 1.1 and 1.2. And furthermore, there exist RFCs which add even more cipher suites to a specific version (e.g. ...
4
votes
1answer
416 views
X.509 algorithm identifier parameters vs. extension values
From the X.509 specs:
AlgorithmIdentifier ::= SEQUENCE {
algorithm OBJECT IDENTIFIER,
parameters ANY DEFINED BY algorithm OPTIONAL }
...
2
votes
1answer
418 views
Why doesn't asn1parse parse all DER encoding strings?
I have a file - crl.txt - that contains the following:
MDYwNKAyoDCGLmh0dHA6Ly93d3cyLnB1YmxpYy10cnVzdC5jb20vY3JsL2N0L2N0cm9vdC5jcmw=
It's from one of the extensions in a particular X.509 cert. Why ...
3
votes
1answer
448 views
parsing the id-ce-keyUsage extension in X.509 certs
I'm trying to decode an X.509 certificate and have a question regarding the decoding of the extensions. In particular, the octet string corresponding to id-ce-keyUsage (OID 2.5.29.15) is as follows:
...
2
votes
3answers
200 views
Help with SSL teaching material
I am taking a course on security next month. As the concepts of SSL/TSL are bit hard. I am looking for a nice way of presenting it to my students. They are Compsci undergrads.
It would be nice to ...
5
votes
2answers
203 views
System for Mutual authenticaion and confidentiality
I am looking for a protocol where there needs to be mutual authentication between client and server. For example server should connect to a particular client only. That is client should authenticate ...
12
votes
2answers
3k views
Which SSL/TLS ciphers can be considered secure?
The OpenSSL website provides a long list of different ciphers available for SSL and TLS.
My question is, which of those ciphers can be considered secure nowadays. I am especially interested in HTTPS, ...
8
votes
3answers
2k views
What are the risks of self signing a certificate for SSL
Let's say I sign a SSL certificate for myself, and I'm not using a certified CA. What are the risks and/or threats of doing it?
7
votes
2answers
258 views
Good resources for learning cryptography and OpenSSL?
I'm a programmer and I'm working on a Single Sign-on project using SAML. I want to do all I can to make this as secure as possible. Since making a secure Single Sign-on/SAML solution requires signing ...
2
votes
2answers
467 views
What should I know before configuring Perfect Forward Secrecy?
PFS has gained attention in our audit department because of its' innate ability to limit our exposure if someone steals our private key.
What pitfalls or common mistakes should I be aware of before ...
2
votes
1answer
255 views
Inspecting a TLS Certificate to determine RSA Key Usage restrictions
With regard to this answer, I have a question about Key Usage in an SSL certificate.
Most SSL server certificates have a RSA key which is not restricted
through a Key Usage extension, so you can ...
11
votes
4answers
6k views
What ciphers should I use in my web server after I configure my SSL certificate?
There are many great questions that ask what is the best certificate to use for a website; but once the certificate is purchased, there is also the possibility to choose or edit the Cipher list.
...
4
votes
2answers
405 views
Which is the easiest secure file transport protocol to implement (SFTP, FTPS, HTTPS, FTP over SSH, FTP over IPsec)
I have to select a secure file transfer protocol, to be implemented in a pre-boot system. I have access to libraries with the basic network functionalities (IP, TCP, UDP, etc...). I might also have ...
1
vote
5answers
2k views
How to properly encrypt a communication channel between a client and a server (without SSL)?
I have a poor knowledge in the world of cryptography, I'm just starting to learn it so I'm a newbie :)
As a project for getting into the field of cryptography I want to write a client\server program ...
4
votes
1answer
169 views
Random number for HTTPS Message Authentication Code (MAC)
Recently I found that Netscape used quite simple algorithm to generate random number for Message Authentication Code to establish an HTTPS connection (Netscape used time, process identification ...
4
votes
3answers
439 views
US export control on open source libraries
I want to ask, is the US export control applicable only to US citizens?
E.g. I think Bouncy Castle are Australians.
Do use of their library fall into export control regulations?
I do not understand ...
21
votes
3answers
2k views
How does Convergence (CA replacement) prevent its notaries from being MITM'd as well?
I have been looking into Convergence and how it works, but I cant figure out how it is effective against a MITM attack that happens near the target system. My understanding is that Convergence works ...
8
votes
3answers
483 views
Does the SSL encryption strength of a website really matter?
When looking to get an SSL certificate one is presented with a lot of options. For example lets take Network Solutions since they have a nice comparison chart.
Immediately there seems to be 4 major ...
130
votes
9answers
8k views
How is it possible that people observing an HTTPS connection being established wouldn't know how to decrypt it?
I've often heard it said that if you're logging in to a website - a bank, GMail, whatever - via HTTPS, that the information you transmit is safe from snooping by 3rd parties. I've always been a little ...
14
votes
3answers
3k views
Convergence - an SSL replacement?
Today, Moxie Marlinspike, a security researcher famous for his research on Android and SSL and related protocols (author of sslstrip/sslsniff), released "Convergence" which says is "an agile ...
4
votes
1answer
319 views
Slow client key exchange in TLS?
I've been benchmarking my TLS performance, and I noticed that during the "write client key exchange" phase, there's significant overhead compared to all other actions. I'm wondering if there's ...
