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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Why can't someone break email or https encryption by somehow getting access to the encryption key?

To repeat, "Why can't someone break email or https encryption by somehow getting access to the encryption key?" In other words, why can't someone intercept the key, or the algorithm to create the ...
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5answers
295 views

Why are private certificates not trusted?

When we go to websites that have generated certificates themselves you see this red screen that says do not go there!: However when it is trusted by some companies it's all good. So I have a couple ...
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3answers
162 views

Using public/private key without signed certificate

I am working on a java program and I am now working on its network security. I want to use a secure connection since it transfers a lot of sensitive information. On all security guides it is mentioned ...
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1answer
84 views

Public Key Cryptography : Key length

While symm. crypt. has around 256 bits of a key, why does public key crypt have a key that is much longer (1000's) ???
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3answers
713 views

Does checking the fingerprint of a self signed certificate improve security?

I am currently developing a component for an application that does TCP communication with a device inside a local area network. I use TLS to provide data encryption, integration and authorisation. ...
6
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3answers
2k views

Managing and storing lots of SSH keys in the cloud

I have a pool of cloud servers (~50) that need to talk to many other remote cloud servers (~4000) using SSH. Each remote server has its own SSH key, so we need a place to store all of these remote ...
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1answer
97 views

Protecting data on an embedded device

I am to release a system-on-chip device that, during its lifetime, will come to store sensitive data. I want to make that data hard to extract or duplicate. Encrypting is good for dealing with MiTM, ...
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2answers
1k views

Cryptography behind chip based credit cards (smart cards)?

Why are chips safer than magnetic stripes? The answers to the above question explain that the chip based cards can not be cloned as the "secret number" is embedded in the chip and protected by the ...
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3answers
423 views

How are private keys handled in an enterprise?

We would like to start using digital signatures and possibly encryption for e-mails in our company. My knowledge of public-key cryptography is entirely theoretical with no practical experience. In ...
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1answer
843 views

Root certificate key usage (non-self-signed end entity)

This discussion does not include self-signed end entity certificates for hosts like web servers and mail servers. OpenSSL's default configuration for a CA certificate has the following keyUsage: ...
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1answer
423 views

How to process or manage Key-Encryption-Key using HSM?

Let's consider two Encryption keys: 1.Data-Encryption-Key(DEK) 2.Key-Encryption-Key(KEK) KEK will be securely stored in HSM, which will be encrypted using master key. Data Encryption Key will be ...
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1answer
310 views

How can a trusted intranet certificate be issued if they are being phased out?

I've just seen this article regarding the phasing out of intranet names on SSL certificates. However, CAs such as this one claim to still issue them and it will be "Trusted by all popular browsers" ...
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1answer
498 views

Which digest algorithm to use with creating a public/private key pair

I'm generating a Public/Private key pair in PHP with the following: <?php $config = array( "digest_alg" => "sha512", "private_key_bits" => 4096, "private_key_type" => ...
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4answers
168 views

search CA for someone's public key

do CAs offer service wherein an application can request someone's public key? i am trying to do this but i am unsure if it is correct (suggestions of better ways to do it will be most appreciated): ...
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2answers
201 views

Nested encryption for multiple users

I've developed a web application (developed in .NET MVC 4) which have multiple users with personal login credentials. The web application holds a lot of content uploaded by the users. My client would ...
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1answer
118 views

Can we build a key exchange protocol without certificates?

Assume that the server and the client both has some secret key K. Is it possible to have a key exchange protocol with authentication between them such that MITM attack cannot hold and if the key is ...
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1answer
484 views

Who is this strangely named Certificate Authority?

I'm researching certificate authorities, and I just have no idea what to think of the CA named x00Ax00-x00Tx00rx00ux00sx00tx00 x00Gx00ex00sx00.x00 x00fx00xFCx00rx00 ...
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3answers
162 views

Governement like classified information system

I need to implement a classification system for my company, similar to the government's. I'm working for a company working with the government. The classification system in my country isn't public so ...
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1answer
120 views

What do people mean by “top-down manner” in X.509 certificates?

What do people mean by saying that X.509 certificates work in "top-down manner"? Do they say that because CAs can do cross certifications?
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1answer
124 views

Learning recommendation for Enterprise PKI design and management?

I'd like to learn the top-shelf methods for designing and managing a generic X509 certificate infrastructure. There's some books here and there, but I figured I'd ask if anyone here has any favorites. ...
2
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1answer
2k views

Why is a CA certificate required for EAP-TLS clients?

When setting up clients with WPA2 EAP-TLS, most clients (ie: my phone, my computer) require both a client public/private keypair (for obvious reasons) and a certificate authority certificate. It's ...
3
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2answers
2k views

How does Authy's 2FA work, if it doesn't connect to the server?

I thought I knew how two-factor authentication works: I enter the password. Server generates a random number (token) and sends it to me via SMS. I enter this token. Server checks that the token I ...
2
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5answers
499 views

Is asymmetric encryption vulnerable to man-in-the-middle attacks?

I'm looking for ways to send private messages over a public channel, and in doing this I stumbled in asymmetric encryption, which is just perfect for what I was looking for at first - A and B ...
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7answers
480 views

Authencity of information displayed on an untrusted device

Suppose I have a (bluetooth/usb) device which needs to displays information on an external pc/phone. Is there a simple and effective method to garantuee that the information displayed hasn't been ...
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1answer
373 views

Is is typical to create both x509 and OpenPGP key pairs?

I'm looking into increasing my use of signed and encrypted "things" - LibreOffice Documents, Off-the-record chat, PDFs, emails, etc. I'm finding that some things only support x509 format-certificates, ...
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1answer
244 views

How is an Authenticode timestamp verified?

For an Authenticode signed file to be verifiable by Windows after the original signing certificate has expired (typically 1-3 years after issue), the file also needs to have a cryptographically signed ...
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3answers
263 views

Certificate Transparency

From what I read here, if the intermediate CA has been compromised, a fake cert can be issued and the privacy of the end-users could be compromised as well. In order to remediate this situation, ...
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1answer
968 views

Self-signed CA and combining wildcard and SAN certificates

I have created my own Certificate Authority and installed the certificate on a few computers. Now I have generated a server certificate with common name *.mydomain.com and Subject Alternative Name ...
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4answers
307 views

Evil certificate authority in public-key-infrastructure

Alice goes to the certificate authority (CA) and registers her public key for signature verification. She gets a certificate for this from the CA. Bob requests Alice' public signature verification key ...
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1answer
256 views

Suggestions on easy distribution/installation of self signed certificates & roots to mobile devices

Suggestions on easy distribution/installation of self signed certificates & roots to mobile devices I am a developer at a government agency in a developing country that has a web application with ...
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2answers
740 views

Client Authentication by certificates in Google APP Engine java

I am writing an application in Google APP Engine java which authenticate the user by its certificate. I have created a self signed certificate using keytool at client side. I also enable the HTTPS ...
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3answers
849 views

In what ways does increasing SSH host key length increase security

I have read on a few guides on "how to secure SSH servers" that it is a good thing to increase ServerKeyBits from the default of 768 to 2048. Most of these guides seem to be for the entry ...
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0answers
49 views

Possibilities for “Service digital identity” field for a service of type http://uri.etsi.org/TrstSvc/Svctype/RA

In ETSI TS 102 231 sec. 5.5.3 Service digital identity, says about "Service digital identity": ... When using public-key technology (i.e. PKI), this field MUST be a representation of the public ...
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4answers
182 views

Changing private keys [closed]

My question is a bit of weird one and doesn't apply to me so much as I'm just curious. My question is: If a large company (say, Google, Facebook, or a bank) were to have its private key stolen, how ...
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3answers
609 views

What stops a hacker from installing it's own CA certificate?

Taking a look at this (now rather old) article about the generated rogue DigiNotar certificates, it states the following: ...Such is the case with that small company in the Netherlands, ...
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1answer
101 views

In theory, can x509 certificates use Accumulator-based revocation schemes? How do these schemes work?

On page 3 of this U-Prove document regarding toke revocation, the author says the benefit of Accumulator-based revocation schemes is A cryptographic accumulator allows the aggregation of a large ...
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1answer
489 views

Additional security for WebRTC/DTLS-SRTP with PGP?

I am having a thought experiment. Can you help me? Two clients who both use PGP. They initiate a WebRTC call using DTLS-SRTP via a 3rd party server. Is there any benefit of encrypting, via their ...
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1answer
219 views

SSL (TLS v1.2) - Can i offer fallback CAs when upgrading Certificates? (Java)

I am currently developing a product that involves two network situations. At the client side, multiple computers form a P2P network (multiple locations, multiple p2p networks), and a subset of nodes ...
3
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2answers
307 views

Totally secure public key distrubition

Public-key cryptography secures communications provided that you use pre-shared public-keys. The problem is how to share these public-keys while maintaining authenticity? How can we be sure that ...
3
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2answers
1k views

Extracting the PGP keyid from the Public key file?

is there a way via an CLI tool or some kind of API to extract the PGP KEY ID from the PGP PUBLIC KEY BLOCK ? I did find the hexa value of the key in the binary file, however I guess the position is ...
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3answers
397 views

accepted naming convention for public keys/certificates

Is there an accepted naming convention for referring to PKI artifacts? There seems to be a lot of confusion with naming of artifacts. For example, it seems that some people refer to: public keys ...
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4answers
300 views

Biometric non revocable major flaw

The major problem with biometric methods of identification is that they are impossible to revoke. Once my fingerprint, under whichever form, is stolen, I can't put it on a worldwide revocation list, ...
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5answers
2k views

Are self-signed certificates actually more secure than CA signed certificates now?

Are self-signed certificates actually more secure than CA signed certificates now? I ask this because recent leaks about the NSA spy programs and the secret FISA courts mean that the US government ...
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4answers
437 views

How can we trust PKI, for example, Verisign?

We want to send an encrypted message to Alice. We can ask her a public key over the network, encrypt with it a message and send that message back. It is bad, because someone can pretend to be Alice ...
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5answers
3k views

Why is Bruce Schneier recommending symmetric crypto over public key crypto

I just read the article written by Bruce Schneier, the crypto guru. In the article, he says : Prefer symmetric cryptography over public-key cryptography. But, he doesn't shed any light as to ...
3
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2answers
208 views

Requirements for qualified certificates in DIRECTIVE 1999/93/EC

DIRECTIVE 1999/93/EC at ANNEX I Requirements for qualified certificates states that one requirement for qualified certificates is (a) an indication that the certificate is issued as a qualified ...
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1answer
86 views

What is the meaning of http://uri.etsi.org/TrstSvc/eSigDir-1999-93-EC-TrustedList/SvcInfoExt/RootCA-QC from ETSI TS 102 231 V3.1.2

From Technical Spec http://uri.etsi.org/TrstSvc/eSigDir-1999-93-EC-TrustedList/SvcInfoExt/RootCA-QC a Root Certification Authority from which a certification path can be established down to ...
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2answers
526 views

Possible to use a YubiKey in HSM mode to secure a Windows CA infrastructure?

I'm looking for a low-cost Hardware Security module, and discovered that YubiKey has a HSM mode. I'm not entirely clear if this HSM mode is what I'm thinking, but I'd like to use it as the offline ...
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1answer
1k views

How do I share my S/MIME public key?

I have setup S/MIME encryption for my email address, and I'd like to allow people to download the public key from my website, rather than having to first receive an email from me. I want the public ...
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1answer
426 views

What are the alternative to PKI certificates in mesh networks?

My particular problem has to do with secure communications over a mesh network (http://en.wikipedia.org/wiki/Mesh_network), in particular man-in-the-middle (MITM) attacks. The difficulty is that mesh ...