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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13 views

Web of Trust: What is “signatory trust”?

I am learning about the Web of Trust and how to use it. However, I have some issues to fully grasp the concept of Signatory Trust. What is an easily understandable definition of signatory trust? An ...
4
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1answer
122 views

Help - Somebody stole my OpenPGP key ID, what can I do?

I received a key transition statement because somebody found himself in the exact same situation described here. This issue will target more and more OpenPGP users in future, probably even all of ...
2
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1answer
23 views

Is there a way of achieving perfect forward security with one directional messages?

Using for example ECDH and ephimeral keys, it is possible for two parties to establish a shared key with perfect forward security, i.e. even if the long term keys are lost, it will not be possible to ...
3
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1answer
52 views

Installing a CA only for specific domains

For many reasons, it's often convenient for organizations to have their own CA (self-signed or otherwise). As I understand it, adding the CA certificate to a OS or browser will make it trust the ...
3
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1answer
55 views

What encryption and signature systems (don't?) allow for plausible deniability of the OP's key being used?

I need to prevent Mallory from blindly matching encryption and signing keys to messages Hypothetical scenario: A user creates a public key An encrypted or signed payload exists. With only public ...
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0answers
68 views

Distribute S/MIME public keys and CA cert for email security

I have my own CA. I want to distribute S/MIME certificates for 10 different users. I saw S/MIME keyservers from http://wiki.cacert.org/KeyServers, but I don't want to use public servers. What is the ...
2
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1answer
53 views

Smartcard - main differences between .NET and Java smartcard?

My question focuses on the differences regarding PKCS11 implementation between a .Net and a Java smartcard. More generally, do smartcard use a specific "OS" (or firmware) and only differ in the ...
1
vote
1answer
36 views

Banking card certificate

Does anyone have an idea of what kind of public-key technologies are used in the bank perimeter ? Does banking card embedded x509 certificate ? OpenPGP ? Perhaps a standard exists or a de-facto ...
3
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1answer
76 views

PKI - Why Root CA is in intermediate CA section?

I can't understand why, when I accept to "install" a custom self signed Root CA on IE browser, the root certificate ends up in the "intermediate CA" section, rather than in "Root CA" section in the ...
5
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1answer
142 views

Should I install my subordinate Certificate Authority on the domain controller? Why?

I must install a PKI in my organization. I work in a windows environment. I already set an offline CA. I must now install a subordinate CA. I have the choice between installing the subordinate CA on a ...
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3answers
82 views

How to avoid identity theft at key signing parties?

Let me begin by distinguishing two kinds of identity theft: Conventional identity theft (e.g. using credentials from ID documents, bank accounts, etc, to commit fraud or other mischief). ...
48
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1answer
3k views

Why does Windows Ship with Expired SSL Certificates?

I am cleaning up the certificate stores on my Windows machines, and considering which certificates I should keep, and which ones I should delete. Why does a fresh install of Windows Server 2012 R2 ...
11
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1answer
198 views

Is TLS in Tor useless?

I am trying to optimize the Orchid Tor client library for my needs and noticed that every connection with every node uses TLS with turned off certificate verification. Actually there are no TLS ...
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0answers
31 views

Use of RSA in Yaksha Security System

So I'm reading over the Yaksha Security System and see it is based on the RSA cryptosystem and a centralized server, easy enough. What I'm slightly confused on is the math behind the related keys. It ...
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2answers
77 views

SHA1 - S/MIME and CRL validity after deprecation?

In an internal PKI using SHA1 for hashing, will S/MIME signature and CRL/ARL signature be considered invalid in the next few years (SHA1 Deprecation) ? End certificates can be revoked, CA ...
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0answers
55 views

How should I organize my keys?

Suppose I have a set of computers with variegate level of trust (for example): I fully trust my own desktop pc at home I trust a bit also my smartphone, but I know it could be stolen I trust a bit ...
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0answers
46 views

Is ADCS overkill just to replace self-signed certs?

Several of our internal applications are either not using SSL certificates, or are using self-signed certificates. I wanted to utilize ADCS to create a trusted, internal-only root CA that our browsers ...
13
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2answers
1k views

Does it matter which key is considered private and which public?

Mathematically, is there a difference which set of characters is private_key and which one is public_key? @Edit At the moment of asking I was thinking on RSA, not asymmetric crypto in general.
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2answers
53 views

Certificates - What about signing again Intermediate CA certificates?

I an thinking about this issue and it is hard to estimate technical impacts. For any relevant reasons, one want to modify one the x509 field of an intermediate CA. This intermediate CA was signed by ...
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2answers
62 views

Subordinate Certification Authorities and managed certificates

How many different certificates can a subordinate certification authority manage? Please, supply me also some reference. Thanks
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2answers
202 views

Encrypt files on FTP server

I have a practical situation here, my company is a FTP server provider for some clients. The clients are sharing their files on our FTP server and have had no problem with access management and ...
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1answer
89 views

PKI - Security concerns when changing a certificate hash algorithm

Suppose I want to change the hash algorithm used for a certificate signature (ex: SHA1 to SHA2). Is it better to revoke the previous certificate and issue a new one with expected hash algorithm ? Or ...
2
votes
1answer
101 views

Why can't I upload a new ECC key to key servers, which is supported by GnuPG 2.1?

My OpenPGP key is soon to expire so I wanted to create a new one. GPG 2.1 came out a month ago including ECC support and I wanted to try the new key types. So I have generated a brand new ed25519 ...
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3answers
168 views

Corporate PKI - SHA1 deprecation

Here is the context. Suppose you have a corporate PKI with : AC_Root (offline in safe store - SHA1 signature) SubRootA and SubrootB (offline in safe store - SHA1 signature) SubSubRootC, SubSubRootD, ...
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1answer
42 views

Definitions of PKCS#11 abbreviations

Is there a complete definition list for all CKx abbreviations in PKCS#11? I believe I gathered most of them: CK = Cryptoki CKA = ... Attribute CKC = ... Certificate type CKD = ... Key derivation ...
2
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3answers
84 views

Email Encryption

I'm hoping someone can point me in the right direction. If I wanted to implement email encryption within an organisation what would be the best way? I've been searching the web tonight but all my ...
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0answers
92 views

Why is the public key extracted from the CSR different than the one extracted from the associated certificate?

I am playing around with pyopenssl. I am trying to extract the public key from a CSR and to check if it is the same than the one I find in the associated certificate. There is a small difference ...
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2answers
48 views

Get the Signature algorithm from a public key? [closed]

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,
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1answer
190 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
55 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
89 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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2answers
1k 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 ...
0
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1answer
238 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
100 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
573 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. ...
6
votes
1answer
3k 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
175 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
vote
1answer
76 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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votes
2answers
221 views

Is “HTTPS” ~100% secure? [duplicate]

Assuming that we have a "green bar connection" to a website, e.g.: Is an attacker still able to sniff our traffic? How secure is a user from man-in-the-middle attacks when he has established a ...
0
votes
0answers
53 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
vote
1answer
84 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
153 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?
0
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5answers
192 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 ...
4
votes
3answers
248 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
312 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
175 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
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1answer
184 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
121 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
147 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 ...
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2answers
185 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 ...