Re: [edlug] Security questions

[Dick Middleton <dick@xxx.xxx.xxx>]

michael calwell wrote:

> I'm trying to get my head around some concepts that have eluded me - 
> notably the mechanics of SSL, SSH and encrypting connections.
>
> First off, does anyone know of any good online primers for these 
> subjects? 

These are from the OpenSSh distro...  the answers should be there 
somewhere.

References -

[0] http://www.openssh.com/faq.html
[1] http://www.lothar.com/tech/crypto/
[2] http://www.aet.tu-cottbus.de/personen/jaenicke/postfix_tls/prngd.html
[3] http://www.gzip.org/zlib/
[4] http://www.openssl.org/
[5] http://www.kernel.org/pub/linux/libs/pam/ (PAM is standard on Solaris
    and HP-UX 11)
[6] http://www.openbsd.org/cgi-bin/man.cgi?query=style&sektion=9
[7] http://www.openssh.com/faq.html

---

it's all made pretty easy really (hiding the reality).  When you install 
ssh some keys are created - the private keys you keep private, the 
public keys can be dunked onto remote systems (in 
~/.ssh/authorized_keys2).  If, when you attempt to log into remote 
system, there is a (public) key which pairs with your private key it 
logs you in.  If there isn't matching key for you then you are 
authenticated using the normal login method (usually defined by pam) 
i.e. it asks you for your password.

Your private keys are normally (but don't have to be) passphrase 
protected - so you need to provide a passphrase to allow ssh to get at 
them.  Since providing these passphrases can be a pain there is a 
separate utility called keychain which will manage the access to your 
private keys on a per-session basis.

N.B. the key files are ascii text files - you add/subtract the keys 
using normal ascii text manipulation tools.

Your public key will usually be found on your local system in 
~/.ssh/id-dsa.pub or ~/.ssh/id-rsa.pub.  The private keys are in a file 
named the same except there is no .pub extension.

Dick







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