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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Besides Browsers, what other Technologies are Impacted by the Deprecation of SHA-1?

I am aware that from January 2017, browsers will start rejecting, or at least warning, users browsing sites offering SHA-1-signed certificates. Would a service be impacted if the system does not ...
0
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0answers
6 views

Where partially homomorphic encryption schemes like BGN are used?

Schemes like Boneh, Goh, and Nissim are interesting, because of support of polynomially many additions and one multiplication. The algorithms are indeed simple https://eprint.iacr.org/2010/182.pdf ...
0
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1answer
31 views

Firefox refuses to use X509 certificate, complaining “Cound not verify this certificate for unknown reasons”

I stumbled upon this question and answer. I have the same problem as the OP, and am sorry to report that the proposed answer does not resolve it. Certificate in question has been verified by OpenSSL-1....
1
vote
1answer
20 views

does openssh support authentication using public key fingerprints?

Cisco have two ways of enabling public key authentication: using the public key and using the public key hash. ip ssh pubkey-chain username <user> key-string <public key> OR ...
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0answers
40 views

Certificate based Access Control for Pub Sub messaging

I'm extending an existing p2p/master Pub Sub framework to support additional security measures, via over the wire encryption and topic based access control. I'd like to use the x.509 certificates that ...
2
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2answers
43 views

CA Certificate Lifecycle

I'm planning to implement a new PKI with 2 tiers of CAs. I'll have end entity certificates with a lifetime of up to 5 years. This means my Issuing CA should be valid for 10 years, in order to be able ...
1
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1answer
80 views

What's the minimal way of sharing your public PGP key in email signature?

What's the minimal (not the entire public key) and secure enough way of sharing your PGP key in an email signature?
0
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1answer
43 views

How to configure SSH public key per user?

I have an OpenSSH server running and different users can log into it with different privileges. I know you can enable public key authentication and place all the allowed public keys in the ...
6
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1answer
83 views

Is there a way to know if a server is using ssh public key or password?

I am wondering is there a way for an attacker through finger printing to find out whether a server is using public-key versus password authentication method for establishing an SSH connection?
8
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1answer
323 views

How can WhatsApp recover messages sent to a damaged phone?

My mom has an Android phone that fell in the water for a couple of seconds, around 16:30. She managed to disassemble the phone and turn it off. We both share a group that is end-to-end encrypted (all ...
6
votes
1answer
119 views

Manually walking through the signature validation of a certificate

Since I am not too familiar with the Web of Trust and Public Key-Infrastructure I decided to learn about it by following the signing chain of a X.509 certificate issued to CN=*wikipedia.org (Serial ...
9
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2answers
529 views

Why SSL uses a third party (certificate authority) yet SSH does not [duplicate]

SSL operations require the use of a trusted third party -- the certificate authority to verify a public key presented by a server to a client. SSH on the other hand relies on the client having the ...
3
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1answer
46 views

Verifying SSH fingerprint of a public server

I have read somewhere that servers which have SSH access for users in the public can have their public key posted publicly (e.g., on a website), so that people who access such a server using SSH can ...
0
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1answer
33 views

PKCS #11 with the TPM

I try to understand PKCS #11 Standard. I found this link. There is this picture. So this picture is in the case of the Trusted Platform Module(TPM). We have the SRK which encrypts with the Private ...
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0answers
47 views

TOTP: Storing symmetrical secrets

I'm in the process of researching 2fa methods for a cloud connected physical access control system. There is very little margin for error in this space. Is it just me or does TOTP for two factor auth ...
0
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0answers
35 views

Migrate a key with a TPM

I try to understand how TPM devices handle the migration of a key. So I found this link: shazkhan.files.wordpress.com (page 4-5) I think I have understood how the rewrap scheme functions, and now I ...
0
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0answers
20 views

Client blocking based on PKI

I've got following scenario: Own PKI in a private network Some webservers in the private network, accessed by load balancing via proxy from the web Now I'd like to block all clients their ...
1
vote
1answer
43 views

Private key and wildcard certificates

I'm trying to understand the implications of private key leakage (due to Heartbleed) from a website that uses a wildcard certificate. If an organization has a wildcard certificate (valid for *.domain....
3
votes
3answers
84 views

Why does PKI use a hash function?

I'll preface my question with my understanding of PKI in case I have any misconception. Owner of domain D generates a public-private key pair (d,e), and constructs a certificate c consisting of (d, ...
0
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1answer
168 views

Is this company's claim to have solved MITM attacks true?

The Daily Mail reported in Dec 2014 about a company that claimed to have solved the MITM attack. Can someone explain how this is possible or what the difference is from TLS?
1
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1answer
295 views

How to make sure that the public key has not been tampered with during transit?

I understand how public key infrastructure works. There is a private and public key, and someone may use the public key to encrypt data that can only be decrypted with the private key. However ...
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0answers
32 views

Use MDC to provide origin authentication for public key encryption?

Why can't we use an manipultation detection code (MDC) to provide origin authentication when using public-key encryption?
2
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1answer
48 views

AuthorizedKeysCommand of sshd_config getting called twice

AuthorizedKeysCommand paramter present in the file /etc/ssh/sshd_config. The bash script which i called using this command is getting called twice. The config file is as follows #RSAAuthentication ...
0
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1answer
48 views

X509 / SSL certificates in practise

After learning the theory behind cryptography I'm having quite some problems understanding how SSL or X509 certificates works in practise and I simply cannot find useful information in the internet. ...
0
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1answer
32 views

Does password protected git public key protect my repository?

When generating my public key for GIT access, I decided to set up a password for it. My push procedure looks like this now: Enter passphrase for key '/c/Users/USERNAME/.ssh/id_rsa': Counting objects: ...
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1answer
34 views

Multi-User-Server Public-Key-Based Authentication

So, lets say we have Alice, John, Peter and Bob. Alice, John and Bob all know Peter's public key and trust Peter. Alice wants to connect to Bob's server, so she presents her public key, which was ...
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2answers
36 views

Why there is time period of key pairs in public key cryptography?

In Public Key Infrastructure, every key pair is associated with its life time. I don't understand why we have a life time when we have functionality such as certificate revocation list(crl) which ...
0
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1answer
49 views

Whatsapp encryption: are the public keys requested from the server every new message or only at session setup?

I was reading trough Whatsapp white paper (and all related questions here) and couldn´f find an answer to this question: are the public keys for the recipient requested by the sender from Whatsapp ...
2
votes
1answer
115 views

What is the difference between a digital signature and whole message encryption?

I am newbie in information security I am trying to understand the difference between a digital signature and encryption of a message. Lets consider simple example of email message. I understand how ...
1
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1answer
32 views

Is there a secure method of distributing keys to network-booted diskless nodes?

I have a bit of an 'initial trust' issue. We are using CoreOS to run Kubernetes, and secure both the etcd API and the Kubernetes API servers using client certificates. We are using iPXE to boot ...
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1answer
53 views

Same certificate but different private keys on different servers. Does this work?

We have a SAN cert that is used on multiple servers. Is it possible to have the cert re-keyed and only use the new private key on a particular server while keeping all of our other servers using the ...
2
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1answer
48 views

What does it mean to sign a public key and what's wrong with signing someone else's key?

I just stumbled upon this comic and I'm not sure if I understand what's going on. I googled and I figured that somehow people can sign other people's public keys and then they that person is genuine. ...
0
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1answer
37 views

How secure is it to bundle unencrypted private key and a CSR into PKCS12 certificate?

I want to create a self-signed certificate to digitally sign my documents. I want to do so using my existing key pair, but to accomplish this I'd have to export my private key unencrypted into a file, ...
0
votes
1answer
45 views

Are there any risks in wrapping asymmetric encryption in symmetric?

The web app I am developing should be end-to-end-encrypted, but for slightly better user experience, I do not want the user to enter private keys into the client. Instead I am planning to store the ...
3
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0answers
61 views

Will WinVerifyTrust return true for a file signed by a revoked certificate, before it was revoked?

I've seen mentions online that drivers that were signed by certificates that were later revoked are still trusted by Windows' driver integrity. Apparently if the file was signed before the revocation ...
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0answers
26 views

key hierarchy management and master key

Now, I have this equation, {{K_ab}K_bs}K_as. K_ab is encrypted by K_bs then whole packet is encrypted by K_as I think the key structure is K_as is the master key, K_bs is under K_as and K_ab is the ...
6
votes
1answer
264 views

Are RSA Key Pairs unique?

I generate RSA key pairs mostly using the following command: ssh-keygen -t rsa -b 4096 -C "someemail@hostname.com" which produces a public-private RSA key pair. If I run this command again and ...
0
votes
1answer
51 views

Review of a protocol

I am wondering if anyone could give a second opinion whether the following is secure or not. I have a system which consist of a mobile device, FTP server and a PC. The mobile device is to upload ...
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0answers
59 views

Key Hierarchy and key Encryption

If i have two 56-bit DES keys, and I use these two key to encrypt a 256-bit AES key. Like this: K_AT encrypts K_BT and K_BT encrypts K What is the effective security of key K? Is it 2 X 56 Bits?
4
votes
1answer
140 views

Safely store passwords in specific scenario

I have a specific network environment. Its a DTN(Delay Tolerant Network) network without continous connectivity, situated on the sea, where nodes are ships. There is also a server that is a part of ...
3
votes
1answer
44 views

What security impact is caused by a TLS server continuing the handshake when presented with an invalid SNI?

RFC 6066 defines Server Name Indication as an extension, whereby virtualised web servers may be given an SNI extension in order to know which certificate should be presented. It has the following to ...
3
votes
3answers
55 views

Is it possible to prove that a TLS server key has changed?

I know of a site that is currently using SSLv2 and I'm refusing to connect to them until they Disable SSLv2 Re-key their servers I'm insisting on #2 because due to DROWN, servers running SSLv2 ...
1
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2answers
103 views

Can I move my private-key to a better token?

I recently purchased a personal signing certificate from GlobalSign - it wasn't cheap either. It arrived yesterday. GlobalSign gave me a "blank" USB security token device - a SafeNet eToken 5100. ...
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0answers
49 views

find owner of private key

On one of the old dev servers I manage there is an RSA public and private key pair ~/.ssh/id_rsa.pub and ~/.ssh/id_rsa in a staging user account (used for automation and testing prior to production)...
4
votes
1answer
96 views

Should 'openssl verify' recognise an exceeded 'Path Length' constraint on a root/intermediate CA?

Background Following the guides here and here I am setting up a multi-level PKI. I have increased the pathlen config to 3, such that I can generate one root certificate that I can use to sign the ...
15
votes
1answer
501 views

How would one verify that the public key from WhatsApp's servers belongs to the person I expect it to?

WhatsApp had recently announced end-to-end encryption on all communications. While that's an impressive move, I still have a big open question mark. The articles and this white paper suggest that the ...
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0answers
150 views

WhatsApp end-to-end encryption for all devices [closed]

The news is out, WhatsApp switched on encryption for a billion people. It supports all devices and encrypts texts, photos, videos and calls. There are so many questions that just came to my mind ...
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1answer
26 views

Impose certificate extensions through the certificate authority instead of the client

As I understand the creation of a x509 certificate is a simple 3 step process: The client generates a private and a public key. The clients generates a certificate signing request for the pair and ...
5
votes
2answers
148 views

Public key for SSH over the internet differs from a key for SSH over the LAN

I have a Raspberry Pi and can access it via SSH (authentication via user password) when my laptop is in the same network. Now I want to access it over the internet. I already set my router to forward ...
0
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2answers
42 views

Does PKI signature verification require secure distribution of public keys?

I'm looking at a software project where the GPG public keys of the maintainers are found on a website using HTTP. According to the GNU Privacy Handbook, "The signature is verified using the ...