Tagged Questions

A public-key infrastructure (PKI) is a set of hardware, software, people, policies, and procedures needed to create, manage, distribute, use, store, and revoke digital certificates. In cryptography, a PKI is an arrangement that binds public keys with respective user identities by means of a ...

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2answers
33 views

Get the Signature algorithm from a public key? [on hold]

When I do PublicKey.getAlgorithm(), it only returns me RSA. Am looking for something to return Sha1RSA. Basically to identify if it is a sha1 or sha2 algorithm. Any help is appreciated. Thanks,
1
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1answer
69 views

Authenticated Diffie Hellman Key Exchange

It appears that the textbook version of Diffie-Hellman is susceptible to man in the middle attack and the use of digital signatures could prevent this attack from occurring. Digital signatures could ...
1
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1answer
29 views

How to understand socat certificate check limitation?

I have set up a certificate-based connection with socat using this tutorial: http://www.dest-unreach.org/socat/doc/socat-openssltunnel.html My socat connection works as following (only the relevant ...
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1answer
56 views

How is PKI used to encrypt an e-mail for multiple recipients?

My understanding is that when an e-mail is encrypted and sent to a recipient, the recipient's public key is used to encrypt the e-mail, and then only the recipient can decrypt it with their private ...
1
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1answer
187 views

SSL interception with Burp Suite using Firefox - Strange behavior when intercepting twitter

I am learning Burp Suite(Free Edition v1.6). I have set it up with the default settings. The proxy listener is listening to 127.0.0.1 on port 8080 and Certificate option is set to 'Generate CA-signed ...
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1answer
232 views

How can the private key be obtained in PKI without alerting a third party? [closed]

For example, I sent a message to Ardi and encrypted it with Ardi's public key. Ardi must decrypt the message with his private key. How can Ardi's private key be obtained in PKI without anyone else ...
2
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2answers
64 views

Distributing public keys; with or without a sub-key?

Most of the public keys I am getting from friends have a sub key in addition to the pub key. For educational purposes I retrieved some public keys and came across this Linus Torvalds' key that does ...
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1answer
49 views

Shall I set “RSAAuthentication yes” in sshd_config if I use only ECDSA key?

In a context of proprietary client boxes and servers, I want to limit authentication to ECDSA keys. Historically, "RSAAuthentication yes" was used to enable authentication with RSA and maybe DSA keys. ...
3
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1answer
138 views

Reset Windows trusted certificates store to its default

Over the time I have installed several additional trusted CA certificates to Windows trust store, sometimes because an app pushed me to do so, some other times for development and testing. Is there ...
1
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2answers
54 views

What's the benefit of hybrid cryptosystem vs asymmetric for small data blocks?

It's a common belief hybrid cryptosystems are better than asymmetric only. Is that allways like that? What's the benefit of using symmetric and asymmetric encryption for small data blocks (< 100 ...
1
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1answer
69 views

How long can a pkcs#8 passphrase be?

A program is using a private key to read messages. To improve security, besides randomness, I'm trying to create the longest passphrase that makes sense. How long should it be? After which amount of ...
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2answers
161 views

Is “HTTPS” ~100% secure? [duplicate]

Before I login to a trusted website, I always check that the address bar has a green padlock and the URL has no typos. E.g: After I've seen the green padlock and checked the domain ...
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0answers
32 views

Attack Vector for Wildcard Cert

So I am looking to the security risks of WildCard Certs, in a previous post most of the questions were answered however I have one follow up question for that. In my instance I use DigiCert, so ...
1
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1answer
63 views

Problem with common factor in RSA [duplicate]

In the RSA key generation steps, what if two entities select a common factor to generate n (i.e. p*q1=n1 and p*q2=n2) resulting in gcd(n1,n2) <> 1 ? This will lead to a problem that everyone ...
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2answers
143 views

With RSA, can one ensure that two entities will not have the same private key?

With the RSA encryption algorithm, is there any guarantee that two different entities will not be given the same private keys?
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5answers
145 views

Are most MiTM attacks done to impersonate web sites, or simply decrypt traffic?

The more I read about impersonating web sites the more I get confused. Does an attacker need the private key of the server in order to impersonate a website or does having the private key simply give ...
3
votes
3answers
134 views

Anonymiszing sensitive data in MySQL DB while retaining searchability [closed]

I have a MySQL database that stores sensitive (personal) data about individuals; and have been tasked with ensuring that this data is encrypted in some way to protect the individuals and their data if ...
1
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1answer
76 views

Recommended Key Usage for a client certificate

My program has the following flow: a client sends a CSR to server, the server sends back a client certificate and after that the client communicate with the server to a path that requires a ...
1
vote
1answer
116 views

Chat encryption system avoiding protocol sniffing and then key+decryption replay?

I'm working on a chat system and I want to add it some kind of security (not just HTTPS with SSL since I've read it can be sniffed and decrypted with a few tools). Now, my knowledge in cryptography is ...
0
votes
1answer
106 views

Why are CA's now signing root certs with SHA2?

I see that CA's are now giving the option of having the root CA cert signed with SHA2. I have been told that the hashing function in a root has no security value, and is irrelevant as far as a ...
2
votes
2answers
65 views

The reason to insert Subject Alternative Names into CA certificate

I am trying to understand meaning of the Subject Alternative Name extension. The reason of usage it in SSL X.509 certificates or other end-entities certificates is mostly clear for me. However, I ...
2
votes
2answers
103 views

Does adding multiple recipients to an encrypted message decrease security?

Let's say you want to send the same GPG/OpenPGP encrypted message to 50+ recipients. Assuming everyone you send to is trusted, and there is no risk of any recipient leaking their secret key, is ...
0
votes
2answers
88 views

Can Subject Alternative Name(SAN) Certificate install on different Web Server or OS?

Let say: application.house.com apache tomcat : physical server email.house.com apache tomcat : virtual finance.house.com Oracle Wallet Manager : physical server ...
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2answers
79 views

Does a smart card do encryption or does it just provide a private certificate?

I don't really understand how smart cards work. Do they sign or encrypt themselves (where the computer provides data to it to sign) or do they provide a computer with the private certificate when I ...
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2answers
188 views

What does 2^77.1 calls presented in a SHA1 attack mean?

Regarding the SHA 1 deprecation, I found this information here: http://blogs.technet.com/b/srd/archive/2013/11/12/security-advisory-2880823-recommendation-to-discontinue-use-of-sha-1.aspx I know ...
2
votes
1answer
67 views

Which PGP settings have been found to be vulnerable?

Digging through articles, one often finds recommendations such as "Use the default key type/size X", whereas an article written a few years later will write "Key type/size X has been found to be ...
3
votes
1answer
143 views

How will SHA1 deprecation affect internal CA's?

I am hearing that the SHA1 Deprecation notices from MS/CHROME only apply to certs that are a part of a public trusted root program. This makes one believe that IE will have new logic built in to allow ...
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1answer
40 views

What happens if my signing subkeys are compromised?

Let's say my subkeys are compromised, but my master keypair is safe and secure, so I revoke the old subkeys and issue new ones. With encryption keys, the results are pretty clear: I can still decrypt ...
4
votes
1answer
58 views

How long do keys stay on keyservers?

Do GPG/PGP keyservers "garbage collect" old keys which have expired, been revoked, or simply haven't been updated in a decade? Or does the server (theoretically) keep every key it has ever seen from ...
3
votes
1answer
156 views

Encrypting/decrypting our license key

We need to provide a license key to customers for our application. The actual license is XML but we need to encrypt it and then in our program decrypt it. I think it is the following, but am asking to ...
3
votes
3answers
84 views

Best practices for GPG user ids

What is the best practice for choosing GPG user id(s)? I've read various bits of advice, which sometimes even contradict each other. For instance, I've read that one should not use comments, because ...
1
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0answers
44 views

Protecting data on a remote device

Background I have am developing a service which consists in a small headless client device (e.g. OLinuXino) which will contain sensitive data. The device will be plugged to a remote network (maybe ...
2
votes
1answer
45 views

Is distinguished subject name at normal SSL Certificate issuance must same as generated Certificate Signing Request (CSR)?

For example: from Issued SSL Certificate: CN = abc.com.my, OU = Room, O = House, c= MY from generated CSR: CN = abc.com.my, OU = Room , O = House, L = KL, ST = KL , C = MY Questions: 1. Is it ...
2
votes
1answer
81 views

OpenVPN: Storage location and creation of keys/certificates?

I am re-setting up some OpenVPN infrastructure to be more secure than the original and wanted some guidance. It's noted that the best security policy is to keep the Certificate Authority (CA) offline ...
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2answers
99 views

Does public key encryption/decryption speed actually matter?

There have been wars fought over RSA, DSA, and I'm sure other public key encryption algorithms, and usually the arguments are "Algorithm A is faster to encode, but algorithm B is faster to decode". ...
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1answer
84 views

Generate public key from private key [closed]

Can we generate a public key from a private key?
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1answer
94 views

Are SSH keys and PGP keys the same thing?

I have a 3072 bit RSA key that I generated for use with SSH. Can this key-pair be used with PGP/GPG, or do I need to generate a new pair of keys separately for use in email encryption? Are the two ...
15
votes
4answers
2k views

Why should I sign data that's already encrypted? [duplicate]

My question is about the difference between signing and encrypting. Why would you still sign something if you are already going to PKI encrypt it? Doesn't the PKI encryption inherently provide ...
0
votes
1answer
41 views

Forward Secrecy not supported with referenced browsers?

I am running a scan against one of our servers from the Qualys SSL tester site and it says that my server "does not support forward secrecy with the referenced browsers". What exactly does that mean? ...
0
votes
1answer
353 views

How are TLSv1.0 ciphers negotiated as TLSv1.2?

I'm a little confused about something I am reading in Bulletproof SSL. "TLS 1.2 is the only protocol that allows suites to define their PRFs. This means that for the suites defined before TLS 1.2 ...
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2answers
110 views

ECDSA ciphers and forward secrecy question about key exchange

I have heard that with forward secrecy that the ECDSA ciphers generate different keys for "each session" because they are not dependent on the private key of the server. My question is how is "each ...
0
votes
1answer
120 views

What would cause a server to only send over 1 SSL certificate to a client? [closed]

We have a secure server that seems to only be sending over the identity certificate. Running the hostname through Qualys says that only 1 cert was provided. The intermediate had to be downloaded on ...
0
votes
0answers
92 views

Do SSH private keys always contain enough information to derive a public key?

I am working on a persistence model for SSH Private keys. The technology used is Java. Since the persistence structure of the public and private keys is pretty similar and using some of the Java APIs ...
1
vote
1answer
78 views

ECDSA/RSA certifcates and cipher selection

In this image can someone tell me if a standard RSA certificate can support the EC*_RSA ciphers listed? If so do you create the typical RSA keys when you are creating the CSR? Also I am fairly ...
0
votes
1answer
74 views

Smart Token Security Test [closed]

I have a question. One of my colleague gave me a Smart Token which consists of public/private key inside and asked me if I can test its security. I said it should be tested in a equipped lab for ...
0
votes
1answer
454 views

What is the deal with Valicert SSL root certificates?

Does anyone know what the status of the "Valicert Class 2 Validation Authority" root certificate is or what's going on with Valicert in general? I've heard that that cert has been deprecated, no ...
1
vote
2answers
99 views

Does where I put my PKI certificates matter?

I have an intermediate and a root PKI certificate that I see were already imported into a computers (windows server 2003) certificate store. However both the intermediate and root certificates were ...
1
vote
0answers
28 views

Key management for hosting applications

We're looking to host a number of client applications in our environment. Some of those will use crypto, e.g. for ssl or database encryption and obviously we'll need to manage keys for that. I am ...
2
votes
4answers
835 views

SSL root certificate optional?

I may have been under the wrong impression on how servers should be setup and what certificates actually get sent over during the server hello certificate message. I came across this today from ...
3
votes
1answer
7k views

Can a CSR be created in OpenSSL with SHA2?

Can a CSR be created in OpenSSL with SHA2? If so, what would the command be and what does this tell the CA, if anything? If you could create a CSR using SHA2 would it "tell" the signing CA to use it ...