Encryption is transforming information through a cipher to protect it.

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89
votes
1answer
23k views

Create a public SSH key from the private key?

Let's suppose I have a SSH key, but I've deleted the public key part. I have the private key part. Is there some way I can regenerate the public key part?
30
votes
7answers
17k views

What is a good solution to encrypt some files in unix?

I am looking for a utility to encrypt certain directories in Linux. I am not looking for any full disk encryption services, but simply to encrypt a few directories for the purposes of storing files in ...
29
votes
13answers
47k views

How to create an SHA-512 hashed password for shadow?

The previous SF questions I've seen have lead to answers that produce MD5 hashed password. Does anyone have a suggestion on to produce an SHA-512 hashed password? I'd prefer a one liner instead of a ...
22
votes
2answers
13k views

I have a keypair. How do I determine the key length?

Using OpenSSL from the command line in Linux, is there some way to examine a key (either public or private) to determine the key size?
21
votes
4answers
6k views

Is data always encrypted in IPv6 communications?

I can't seem to get a straight answer to this quesion. Wikipedia says "IPsec is an integral part of the base protocol suite in IPv6," but does that mean that ALL communications are always encrypted, ...
20
votes
4answers
1k views

Are encrypted backups a good idea?

I'm in charge of a small set of laptops and wanted to get some sort of automated remote (over WAN) backups going; the backups would be going to a RAID drive. Because we don't really have a secure ...
19
votes
8answers
21k views

What impact does full hard drive encryption have on performance?

We have HP notebooks here at work, and it is policy to have HP's hard drive encryption turned on to protect client databases and IP in the case of loss/theft. I was wondering if there was any ...
16
votes
7answers
4k views

Easiest way to send encrypted email?

To comply with Massachusetts's new personal information protection law, my company needs to (among other things) ensure that anytime personal information is sent via email, it's encrypted. What is the ...
15
votes
3answers
2k views

Tape encryption management & best practices

I want to enable encryption on all of my backup tapes. I more-or-less know how to do this technically, but the procedural and human elements of implementing this are tricky. I use HP LTO4 drives ...
13
votes
2answers
613 views

Why do my two ssh public keys have the same beginning?

I was updating the authorized_keys file on my server with the public key for the new laptop I got and I was surprised to discover that the two public keys began the same: # key 1 ssh-rsa ...
13
votes
5answers
984 views

Encrypted offsite backups - where to store the encryption key?

In addition to regular onsite backups (kept in a fire resistant safe), we also send tapes offsite once a month, encrypted with AES. So if our site is one day vaporised by an alien heat ray, we should ...
13
votes
3answers
6k views

How to disable swap files in ESXi?

We are running a few Solaris / Linux VMs on ESXi that contain very sensitive encrypted data that eventually get decrypted as required in memory. Everything is fine, except for the ESXi swap files ...
12
votes
6answers
19k views

How can I disable encryption on openssh?

I'm having performance problems using openshh(server) and putty(client) combination to use a remote webproxy. I'd like to disable encryption and test the results to see if it makes a difference. How ...
11
votes
2answers
4k views

GPG - why am I encrypting with subkey instead of primary key?

When encrypting a file to send to a collaborator, I see this message: gpg: using subkey XXXX instead of primary key YYYY Why would that be? I've noticed that when they send me an encrypted file, ...
11
votes
2answers
6k views

How secure is the encryption used by Microsoft Office 2007?

I've read various articles about Microsoft's Office 2007 encryption and from what I gather 2007 is secure using all default options due to it using AES, and 2000 and 2003 can be configured secure by ...
11
votes
2answers
844 views

Encryption over gigabit carrier ethernet

I would like to encrypt traffic between two data centres. Communication between the sites is provided as a standard provider bridge (s-vlan/802.1ad), so that our local vlan tags (c-vlan/802.1q) are ...
10
votes
4answers
32k views

How can I see what version of SSL a web server is currently using?

I believe I have disabled SSL 2.0 on my web server (Windows Server 2003). To make sure that it is now using SSL 3.0, how can I check this? What is the correct way to disable 2.0 and enable 3.0 on a ...
10
votes
1answer
9k views

Is POST data encrypted over an SSL connection?

I've set up my web server to use SSL (I'm using WAMP for my staging scenario before I move it on up to public servers). The purpose of the site at hand has succeeded and I am able to use the site from ...
10
votes
3answers
6k views

SSL Certificate Class 2 vs Class 3 vs Class 4

I just got a "Premium EV SSL Certificate" form GoDaddy.com. Apparently as of 8 months ago GoDaddy doesn't provide Class 3 Certificates. ...
10
votes
3answers
2k views

Mysql Encryption and Key managment

I am developing a local intranet system in PHP/MySQL to manage our client data. It seems that the best practice would be to encrypt the sensitive data on the MYSQL server as it is being entered. I ...
9
votes
3answers
504 views

Why does a web server's public key certificate have to be signed by a certificate authority?

In other words, what would be the security risk of not signing public key certificates by certificate authorites (from a user perspective)? I mean, the data is still encrypted... What could a man in ...
9
votes
3answers
1k views

RSA or DSA: What's the definitive answer when generating SSH key pairs? [duplicate]

Possible Duplicate: SSH keypair generation: RSA or DSA? Some say use RSA, some say use DSA, some say it doesn't matter. Some say one is more secure than the other, some say the reverse. ...
9
votes
2answers
2k views

Encrypt git repository on server (safe against theft of physical hardware)

I have a production server (Ubuntu, running 24/7) with a git repository and some client computers each with a working copy of this repository. In the client computers, simply using home folder ...
8
votes
9answers
6k views

How secure are passwords with under 20 characters length?

I recently received a recommandation for setting my password to above 20 characters. The algorithm used for encryption is AES with a 256 bit primary key. How secure is a, let's say, 8 char password ...
8
votes
3answers
2k views

ZFS RAID and LUKS encryption in Linux

I'm planning to setup a set of 3x 2TB 7200rpm drives as a LUKS-encrypted Z-RAID pool in Linux (for a NAS solution). My understanding of the problem at hand is that the only way to achieve this is to ...
8
votes
4answers
1k views

Encrypt temporary password using public ssh key

I manage a virtual office and our staff uses both SSH keys and passwords for authentication. If one of our staff forgets his password, is there a way to encrypt a temporary password using his public ...
8
votes
5answers
5k views

OSX - Full Disk Encryption [closed]

What options are available for OSX full disk encryption? Which of them is the best?
8
votes
1answer
5k views

How does the ssh-keygen .pub format work with .pem files?

The ssh-keygen command generates .pub files which it describes as "public key files", but they are a totally different format to most "public key files" I've usually seen, which are in PEM format. ...
8
votes
3answers
3k views

How to create a randomly keyed, encrypted swap partition, referring to it “by-uuid”, on Debian?

It is sensible that if you have any sort of block device encryption implemented on your GNU/Linux system, to encrypt your swap partition too, as any decrypted data may be written in cleartext at any ...
7
votes
3answers
6k views

Is STARTTLS more safe than TLS/SSL?

In Thunderbird (and I assume in many other clients, too) I have the option to choose between "SSL/TLS" and "STARTTLS". As far as I understand it, "STARTTLS" means in simple words "encrypt if both ...
7
votes
3answers
13k views

Can I create my own S/MIME certificate for email encryption?

I'm having a bit of an issue here. Bear with me as this may be a case of "not asking the right question". Background: Using Apple Mail. Want to encrypt/decrypt email but GPGMail (and apparently ...
7
votes
6answers
3k views

Truecrypt: File vs Device hosted encryption

TrueCrypt allows the user to create an encryption volume on a file or a device hosted encryption on a drive or partition.What is advantage or disadvantage of one over the other?
7
votes
6answers
20k views

How should someone create an encrypted password for /etc/shadow?

I am setting up a new account on a Linux box for Subversion repository access, and can send the password to the new user. However, I think there was a command line utility for this new user to encrypt ...
7
votes
3answers
9k views

How secure are password-protected WinRAR archives?

The web seems to be flooded by password removers. I'm however on the other side. I'm interested in security of my files. If I have a WinRAR archive (> 1 Mbyte) and use a password (> 6 characters ...
7
votes
2answers
10k views

Is MySQL port 3306 encrypted, and if no, how can I encrypt it?

I am working through a security audit for a system at my work and one of the requirements is to encrypt all traffic through public/unprotected networks. Since we are accessing the MySQL database (over ...
7
votes
3answers
5k views

Encrypted Remote Backups via Rsync?

I run a small modest CentOS server at my house for misc backups, etc. My friend on the other side of town also runs a small modest server at his house for similar purposes. We have been toying with ...
7
votes
2answers
1k views

Approaches for Linux server disk encryption

What are the approaches available for fully encrypting a disk on a remote server (say, colocated in a datacenter)? On Windows, we can just turn on Bitlocker with a TPM. Then the server can reboot, and ...
7
votes
2answers
3k views

What's the best practice for taking MySQL dump, encrypting it and then pushing to s3?

This current project requires that the DB be dumped, encrypted and pushed to s3. I'm wondering what might be some "best practices" for such a task. As of now I'm using a pretty straight ahead method ...
7
votes
3answers
5k views

IPSec for LAN traffic: Basic considerations?

This is a follow-up to my Encrypting absolutely everything... question. Important: This is not about the more usual IPSec setup, where you want to encrypt traffic between two LANs. My basic goal is ...
7
votes
1answer
408 views

State of hardware-assisted disk encryption in Linux

I use dm-crypt to encrypt partitions. I am building a small office server from consumer (or pro-sumer) category hardware. It made me wonder, hardware-assisted encryption is a notion in the air for ...
6
votes
4answers
377 views

How secure are wireless networks?

If I'm on an open wireless network, can a 3rd party capture packets and see all the internet traffic to and from my computer? What if WPA encryption is used, but someone has the key already? If I use ...
6
votes
2answers
1k views

Is it possible to have a 100% secure virtual private server?

I am curious if it is possible to have a VPS that has data on it that is not readable by the hosting provider, but is still usable on the VPS. Obviously there are some things that you could do to ...
6
votes
2answers
3k views

Are there huge drawbacks to using an excel 2010 document for password management?

At my old job, we used an open-source, (IMO) secure method for managing network infrastructure, and other important hosts' passwords [with Keepass]. At my new job however, it seems like they're using ...
6
votes
3answers
3k views

Is it possible to hardware accelerate LUKS encryption?

My Linux server spends a lot of time computing LUKS encryption. Is there any way to hardware accelerate it (with a PCI express card for example)?
6
votes
3answers
245 views

Sending HIPAA compliant e-mails

At a small office, my clients' HR department needs to communicate with some vendors regarding HIPAA-covered material. How do most companies deal with securely sending e-mails regarding HIPAA. I ...
6
votes
2answers
4k views

Certificates in SQL Server 2008

I need to implement SSL for transmissions between my application and Sql Server 2008. I am using Windows 7, Sql Server 2008, Sql Server Management Studio, and my application is written in c#. I was ...
6
votes
3answers
215 views

General GnuPG tips

Prompted by the recent vulnerability in SHA-1 and admonitions to begin the process of moving away from that hash function, I'm playing around with GnuPG again. I was just wondering how other folks ...
5
votes
5answers
11k views

Are 128 and 256bit AES encryption considered weak?

Are 128 and 256bit AES encryption considered weak? I wanted to archive files and i figure i can write an app to automatically do it with winrar or 7z. Winrar uses AES-128 and 7z uses AES-256. I was ...
5
votes
5answers
1k views

Ubuntu 10.4 Full Disk Encryption

Is it possible to setup full disk encryption for Ubuntu 10.4 server? Either natively or with Truecrypt? Additionally, is this something that has to be done at the time of installing the OS, or can it ...
5
votes
5answers
653 views

Sharing public key with ssh

Is it possible to somehow setup an ssh server that doesn't require a username,password or cert to login? If that's not possible, if I were to give all customers the same public key, would each ...