A piece of data used in public key cryptography that contains identifying information (i.e. email address or web address), a hash of a public key, and a digital signature that authenticates the data in the certificate.

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2answers
105 views

Why do certificate authorities often require/use multiple intermediates?

I suppose this is related to What is an intermediate certificate authority? but I think my question is a bit different so I'll ask it anyway. Why do most modern certificate authorities (e.g. ...
6
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2answers
2k views

Are certificate authorities required to obey to the signature algorithm (hashing) specified in the CSR?

I was playing a little bit with signature algorithms, trying to determine which CAs among the ones I use are currently issuing SHA2 certificates. I generated a CSR specifying the SHA256 hash (either ...
2
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1answer
558 views

Intercepting HTTPS Android app traffic

I'm trying to intercept Android application traffic from my Android phone....Basically what worked before was that i had simply installed fiddler proxy on my PC, exported the root certificate (and ...
-2
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2answers
167 views

How do certificates stop this man in the middle attack?

Alice and Bob are trying to set up a secure conversation, but unknown to them in the middle is Eve, who can intercept and modify all packets sent between them. The communication goes as follows: ...
3
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1answer
94 views

Why do Certificate Authorites cross-sign each other?

A Certificate Authority (CA) issues digital certificates to certify the ownership of a public key by the named subject of the certificate. What is the rationale for CAs cross-signing each other (i.e. ...
0
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1answer
66 views

Is it possible for a successful domain hijacker to fraudulently use the certificate issued to the real owner of the domain name?

In other words, while visiting https://www.mybank.com, for example, can I always trust the site as long as I click the padlock in the address bar of my browser and find no problem with the ...
1
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2answers
198 views

Are there other roots of trust on my computer aside from these 46 root certificates?

I've heard many people imply that modern browsers and OSes trust a myriad of root certificates. The implication is that it is impossible to ensure the private keys of all of the root certificates ...
2
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1answer
105 views

Is an SSL/TLS HTTPS certificate 'fingerprinting' attack possible?

If you download a friend's site's unique HTTPS root certificate (independent of default browser-shipped ones), or you simply make a 'permanent exception' to an obscure self-signed cert, in Firefox, I ...
3
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2answers
114 views

Can CA issue a certificate without CSR?

My question is if the CA can generate a private/public keypair on behalf of the requestor and sign it with its own private key? Is there any standard way or protocol to distribute such a ...
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4answers
5k views

inquiry about SHA1 with RSA for certificate signature

As you all know, plenty of X.509 Certificates use (PKCS#1 SHA1 with RSA encryption) as the Certificate Signature Algorithm for generating the signature of 2048 Bits long. We know that SHA1 hash ...
102
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6answers
10k views

I can't access websites that use HTTPS, instead getting the message “your connection is not private”!

I found myself suddenly unable to access websites that use HTTPS, so I contacted my service provider, and they asked me to install a certificate in the Trusted Root Certificate Authorities store. But ...
2
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2answers
103 views

Using digital certificates in digital signatures

Please could anybody explain to me how certificates are used with digital signatures? I understand difference between certificates and signatures. It is clear. Digital certificates are used to ...
4
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1answer
39 views

Mail Signing Certificate – What are the impacts when revocated?

Suppose I open a signed mail on 1st January 2000, signature is OK. What about this two cases : 1) If next CRL is to be published one week later, I found it strange that it is “probably” valid until ...
4
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3answers
45 views

Certificate Issuer is Network Company

I simply want to know if is this normal, abnormal, deceptive, illegal, etc... I am at work. When I bring up a certificate for most domains, I get a very standard certificate. When I bring one up for ...
2
votes
3answers
420 views

Forged SSL without installation of root CA, possible?

Consider visiting a secure website like Gmail. Is it possible to forge the website certificate only by having full control over the internet provider? I mean is it practically possible for a provider ...
1
vote
2answers
408 views

Does Renewing SSL certificate change its thumbprint / Fingerprint

I would like to know, if renewing a SSL certificate will change my thumbprint? The certificate has expired. If it can be same then under what conditions can it remain same. Many thanks in advance.
3
votes
3answers
310 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, ...
2
votes
1answer
71 views

Is client cert authentication with a 3rd party PKI cert any safer than using self-signed?

I am working on a small M2M project (a few hundred nodes connected to a single cloud server), and want to use client certificate authentication, with each client getting its own unique cert at ...
0
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2answers
67 views

Current standard of authentification

What is the current standard of authentification? I thought it is server and client authentification. But I typed for e.g. https://www.google.com/ and checked the packages in wireshark. And there ...
1
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1answer
68 views

Digital signatures and weak hash functions

There was this question in last year's exam. The teacher claims that answer b) (in boldface below) is correct. Attacks are constantly being performed on digital signatures which use weak hash ...
0
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1answer
56 views

Obtain X.509 Certificate Fingerprint from Certificate Info

I would like to obtain the SHA1/MD5 fingerprint of an X.509 certificate in order to compare it with the one presented by a server before connecting. However, I currently don't have access to the ...
0
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2answers
210 views

Security of SSL certificates bought via resellers

There are many SSL certificate resellers - some are well known enterprises with good reputation (e.g. domain name registrars) while others are small and unknown companies. It is clear that resellers ...
2
votes
1answer
50 views

Website Implementing https site w/ self signed certs and CA

Q: How best to handle the issue of security warnings for a website using certificates from its own CA (ie, selfsigned)? I am some what torn on how to do this - I have a number of implementaiton ...
4
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3answers
1k views

Is it possible to modify a CA without having to reissue all of the derived certificates?

Background: I have my own authoritative certificate that I generated myself for signing certificates for services my friends and I use, including web server, ircd, etc. It's convenient because I ...
2
votes
1answer
484 views

CSR from IIS 8 and Keeping my Private Key a Secret

I've been trying to understand something. When you generate a CSR from IIS, how is the private key kept as a secret, or is it? Do CA's email you a certificate that includes your private key? Because ...
5
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1answer
56 views

Protecting information in TLS client certificates

If I understood correctly, when using TLS with client authentication, the client certificate is transmitted to the server in plain text. The client certificate might include personal information, ...
3
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2answers
2k views

How To Recover EFS Cert From Backup?

I made a backup of the old Win 7 Pro then did a clean install. But I forgot to export my EFS encryption certificate, so when after I restored the encrypted files from backup I could no longer access ...
2
votes
2answers
177 views

Does Ephemeral Diffie-Hellman require a certificate?

In Ephemeral Diffie-Hellman, the key pair is generated every time. In practice, does this mean I never need a certificate? Or that means I need a new cert every single time?
4
votes
2answers
124 views

Why not generate a client SSL with expiration date in very distant future?

In case of server SSL certificate it is issued by a CA which can then recall it until it expired and also the CA typically collects a fee for each certificate so it is interested in certificates ...
4
votes
1answer
92 views

Wildcard SSL and EV SSL

Is it possible to mix a Wildcard SSL for subdomains and an EV SSL for the www and non-www domain? I know that an EV SSL can't have a wildcard. Example: hello.test.com -> wildcard ssl ...
1
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2answers
222 views

In detail, how does SSL offloading/acceleration/termination work?

What is the in-depth working mechanism of SSL offloading/termination? I could not find literature that would dive deep enough into the subject. Assume the following example, where a intends to ...
2
votes
1answer
210 views

Openssl adding a telephone number or cell number to the distinguished_name

In the openssl.cnf file, I see fields like countryName, stateOrProvinceName etc which are typically present in the distinguished_name. Where can I get a list of fields which can be added to the ...
-1
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1answer
27 views

What if I have an address-based certificate and a domain based certificate loading HTTPs resources in the background

What if I have an address-based certificate and a domain based certificate loading HTTPs resources in the background, will this change the Lock-Logo in the Browser Address bar? Does an address based ...
3
votes
1answer
78 views

Email, Certificates and DANE [closed]

Does DANE offer the ability to provide certificates for services? Or is it just hosts? How does one specify a mail server with DANE? If my email is jd@foo.com but mail.bar.com is the email server, ...
0
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1answer
121 views

What does this mismatching SSL certificate hint at?

I'm currently visiting China, and I use a well known VPN service for both my laptop and my phone. Every now and then, I get certificate errors when using my phone when I'm connected to a VPN, but ...
1
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1answer
73 views

Multi-Function SSL Digital Certificate

Is there a problem with using a single SSL certificate for both SSL/TLS/HTTPS communication as well as to sign (external) digital timestamp certificates? Other than the obvious: if one key is ...
1
vote
2answers
2k views

My certificate seems fine but my TLS fails (Cert not validated)

I set up my certificate for my mail server at https://mail.xxxx.com/ I exported my certificate as described in my mail servers documentation and pointed to it in the server settings. The certificate ...
2
votes
2answers
186 views

Why gpg-signed files differ every time

I signed the same file producing a separate file for the signatures, and I noticed that every file is signed with a different signature. I don't get it. Shouldn't it always be signed with the same ...
2
votes
1answer
103 views

How does firefox know when to display a green bar?

Recently I've been working on creating a self signed CA and had some success. Now I have a working CA with valid CRL server. The root CA has been deployed to all of my devices and had no problem. ...
3
votes
1answer
60 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 ...
0
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0answers
58 views

Self-signed certificates, CA and stacking

I have a server running a number of virtual hosts. I have setup as a "self-CA" and then created and signed certs for each of the virtual hosts. In running the SSL labs testing, it always complains ...
0
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2answers
81 views

How do certificates work in protecting against a man-in-the-middle attack? [duplicate]

As I understand it, if Alice and Bob wants to communicate securely, they must first agree on the protocols that will be used. Then they must confirm that they are indeed communicating with each other. ...
0
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0answers
24 views

Difference between SSL versions and TLS versions? [duplicate]

Can anyone tell me the different versions of SSL and TLS? Someone says that SSL 1.0 was never released or never exist and other says that SSL 3.0 = TLS 1.0? Can anyone please clarify? Actually I am ...
1
vote
2answers
153 views

Should every SAML identity provider provide a unique public certificate to the service provider?

When accepting public keys from someone setting up an identity provider for access to resources protected by a service provider using SAML 2.0, do you absolutely need to have a unique certificate? Is ...
0
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2answers
153 views

Typical mistakes when implementing digital signatures?

I am looking for a list of typical mistakes someone can make when implementing digital signatures for a software. And of course why they are mistakes and how an attacker could take advantage of them. ...
1
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0answers
100 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 ...
1
vote
1answer
65 views

SSL with client certificate authentication

can somebody explain to me if for example i use Server certificate, with 2048bit keys and client certificate with only 512bit strength, does this use in any way affect the security of the established ...
8
votes
3answers
789 views

Does the SSL encryption strength or validation level 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 ...
1
vote
1answer
266 views

How can I convert a Windows certificate into a PEM format, that includes the chain + root?

I need to import a certificate into a Cisco Ironport for Web SSL inspection. The only input format supported is PEM. Based on my research the PEM format does support all certificates in the chain, ...
2
votes
2answers
72 views

Is it possible to use an open collection of default SSL certificates for my browser?

Browsers and OSes come with a set of default SSL certificates for well known organizations, such as root certificates from CAs. I understand that the trust model is as follows: I pick (actually my ...