their key's "fingerprint" to them.

tiresome (ASCII-armored) key to them over the phone, you can just read

and verify their key over the telephone.  Rather than reading their whole

know this person and would recognize them on the phone, is to call them

the one you received the key through.  One convenient way to tell, if you

uncertified key is to verify it over some independent channel other than

trust, how can you tell if it's really their key?  The best way to verify an

If you get a public key from someone that is not certified by anyone you



to get the key trust network started for your circle of friends.

sign each other's keys with confidence.  This is a safe and convenient way

her end.  You can both verify each other's keys this way, and then you can

phone, while she checks it against her own, using the same  command at

key components.  Read this 16-byte fingerprint to the key's owner on the

This command will display the key with the 16-byte digest of the public



• Fingerprint key...



certificate.

extract your public key together with the attached revocation

public keyring.   Then use the "extract" command (see above) to

"revocation certificate" will be  attached to your public key in your

This command is also used to revoke your own key. In this case a

completely lost (in which case it should be removed) but "on hold".

keyfile.  This is useful to indicate that the trust of the key is not

This command can be used to temporarily enable or disable keys in a



• Disable/enable key...



accordingly.

trustworthy so that PGP will update trust values for affected keys

You can use this to indicate that a signature is no longer considered

Use this command to remove the signatures associated with a given key.



• Remove signatures...



other user IDs intact.

to remove only the user ID you specified, while leaving the key and its

If more than one user ID exists for this key, you will be asked if you want



file name.

you want to remove a secret key.  You may specify a different key ring

"pubring.pgp".  It can be omitted, or you can specify "secring.pgp" if

for a match.  The optional keyring file name is assumed to be literally

it finds a match.  Remember that any fragment of the user ID will suffice

PGP searches for the specified user ID in your key ring, and removes it if

Use this command to remove a key or a user ID from your public key ring.



• Remove Key...



allows people to better choose who they can trust for key management."

reflects the natural way humans interact on a personal social level, and

emphasize this organic decentralized non-institutional approach.  It better

probably work better than a centralized key server.  PGP tends to

allowing all users to act as a trusted introducers for their friends would

"For more decentralized grassroots 'guerrilla style' environments,



from Tampering" in the Special Topics volume:

own scheme.  Phil Zimmerman writes under "How to Protect Public Keys

authorities and hierarchies" but PGP simply lets the user choose their

Complex systems and structures have been proposed for "certifying

to a "spoofing" attack whereby the intermediary supplies a false key.

If you received the key for a person via a third party, you are susceptible

the trust parameters are a method of judging the authenticity of the keys.

Valid?" in the Essential Topics volume of the PGP User's Guide.  In short,

mean, see the section "How Does PGP Keep Track of Which Keys are

your public key ring.  For a discussion on what these trust parameters

Sometimes you need to alter the trust parameters for a public key on



up your key on the key ring.

more than one user ID to your key, any one of which may be used to look

more than one name or E-mail address or job title.  PGP lets you attach

add a second or third user ID to your key, because you may be known by

name, or maybe you changed your E-mail address.  Or maybe you want to

need to change your user ID, because you got married and changed your

someone looked over your shoulder while you typed it in.  Or you may

Sometimes you may need to change your pass phrase, perhaps because



the pass phrase for your secret key.

someone else's key, to edit your userid on your public key, or to change

Use this command to change the trust parameters associated with



• Edit Key...



the Essential Topics volume.

Tampering" and "How Does PGP Keep Track of Which Keys are Valid?" in

For further details, see the sections "How to Protect Public Keys from



trusting the key's owner.

wouldn't trust that key's owner.  Trusting a key is not the same as

belonging to him because you signed it (assuming they trust you), but they

that the key really belonged to him.  Other people would accept that key as

by signing the public key of a sociopath, if you were completely confident

ownership) of that person's public key.  You aren't risking your credibility

for the integrity of that person, but only vouches for the integrity (the

Bear in mind that your signature on a public key certificate does not vouch



the Phone" in the Special Topics volume for further details.

"Fingerprint key" command and the section "Verifying a Public Key Over

her key-and make sure you really are talking to the right person.  See the

the key file to her to get her to confirm that the key you have really is

that key.  Perhaps you could call the key's owner on the phone and read

should require your own independent firsthand knowledge of who owns

from trusted introducers should suffice.  But to sign a key yourself, you

To be convinced of a key's validity enough to use it, certifying signatures

ownership than if you merely want to use that key to encrypt a message.

In order to sign a public key, you must be far more certain of that key's



from her.

belongs to her.  Preferably, you should sign it only if you got it directly

public key unless you have independent firsthand knowledge that it really

your signature.  It may be ill-advised to rely on hearsay-- don't sign her

Other people who trust you will accept her public key because it bears

certificate is a promise by you that this public key really belongs to her.

public key certificate.  This is because your signature on her public key

certain that it really belongs to that person named in the user ID of that

If you are asked to sign someone else's public key certificate, make



'introducer' for that key to others by passing them the certificate.

you to attest its authenticity.  You serve as the intermediate trusted

genuine.  A file 'certificate' is created holding their public key signed by

Use this command to certify someone else's key in your keyring as



• Certify Key



Options menu.

suitable for email purposes, use the "ASCII Output" flag under the

If you want the extracted key represented in printable ASCII characters



they are copied off along with the key.

If the key has any certifying signatures attached to it on your key ring,



approach used to give a copy of your public key to someone else.

your public or secret key ring to the specified key file.  This is the

ring.  This non-destructively copies the key specified by the user ID from

Use this command to extract (copy) a key from your public or secret key



• Extract Key...



the Essential Topics volume.

Tampering" and "How Does PGP Keep Track of Which Keys are Valid?" in

For further details, see the sections "How to Protect Public Keys from



write-protected media.

automatically compare your public key against a backup copy on

your own ultimately-trusted public key, PGP can be set up to

important key to protect from tampering.  To detect any tampering of

or indirectly certify all the other keys on your key ring, it is the most

Since your own trusted public key is used as a final authority to directly



key ring.

maintenance periodically to make sure nothing is wrong with your public

write-protected floppy disk.  It may be a good idea to do this hygienic

checking your own ultimately-trusted key against a backup copy on a

checking the trust parameters, updating all the validity scores, and

analysis of your public key ring, checking all the certifying signatures,

you may want to explicitly force PGP to perform a comprehensive

material is added to or deleted from your public key ring.  But perhaps

In theory, it keeps all the key validity status information up to date as

public key ring and updates all the trust parameters and validity scores.

Normally, PGP automatically checks any new keys or signatures on your



parameters and validity scores associated with keys are derived.

signatures of introducers attesting to authenticity, from which trust

key ring check command.  Associated with the keys in a keyring are

To have MacPGP perform a full analysis of your public key ring, use the



• Check signatures...



"verbose" flag under the Options menu.

To see all the certifying signatures attached to each key, use the



want to specify a different key ring file name, you can.

you can specify "secring.pgp" if you want to list secret keys.  If you

keyring file name is assumed to be "pubring.pgp".  It can be omitted, or

omit the user ID, all of the keys in the key ring are listed.  The optional

any keys in the key ring that match the specified user ID substring.  If you

Use this command to view the contents of your public key ring.  This lists



• View keyring...



already have on your key ring.

merges in any new certifying signatures for that key that you don't

added with the key.  If the key is already on your key ring, PGP just

key being added has attached signatures certifying it, the signatures are

keys in the keyfile are added to the keyring, except for duplicates.  If the

If the key is already on your key ring, PGP will not add it again.  All of the



"Options" menu.

secret key.  You may specify a different key ring file name under the

"secring.pgp", depending on whether the keyfile contains a public or a

The optional keyring file name defaults to "pubring.pgp" or



key file may contain multiple keys.

public or secret key ring (note that [brackets] denote an optional field).  A

Use this command to add a public or secret key file's contents to your



• Add keys...



from the existence of a secure "revocation certificates".

in that people are being asked to make key modifications on faith and not

Also, whenever this happens, it weakens the security of the 'trust web'

pair, who have to communicate with you and replace it with your new one.

will cause inconvenience to everyone who holds that public key half of the

storage media or carelessness-make backups!  If you lose your key you

Make sure you don't lose your unique public and private key pair to faulty



your own personal computer.

exposing it by storing it on a remote timesharing computer.  Keep it on

pair.  Always keep physical control of your secret key, and don't risk

make key pairs for your friends.  Everyone should make their own key

Never give your secret key to anyone else.  For the same reason, don't



protected with its own pass phrase.

your secret key ring.  Each secret key on a key ring is individually

you keep your secret key file to yourself, and you should include it on

be sent to your friends for inclusion in their public key rings.  Naturally,

key file suitable for distribution to your friends.  The public key file can

new public key from your public key ring and place it in a separate public

You can later use the "Extract" command option to extract (copy) your

The generated key pair will be placed on your public and secret key rings.



lengthy process.

keystrokes with a fast timer.  Note that RSA key generation is a VERY

random numbers generated from measuring the intervals between your

The public/secret key pair is derived from the RSA process and large



prompt.

phrase (You fool!), just press return (or enter) at the pass phrase

see it, and don't store it on your computer.  If you don't want a pass

screen.  Don't leave it written down anywhere where someone else can

and should not be too short or easy to guess.  It is never displayed on the

every time you use your secret key.  The pass phrase is case-sensitive,

to recover it if you do lose it.  This pass phrase will be needed later

anything else you want in it.  Don't lose this pass phrase-there's no way

be a whole phrase or sentence with many words, spaces, punctuation, or

this pass phrase.  The pass phrase is like a password, except that it can

falls into the wrong hands.  Nobody can use your secret key file without

PGP also asks for a "pass phrase" to protect your secret key in case it



unique information that would help ensure that your user ID is unique.

If you don't have an E-mail address, use your phone number or some other



    Robert M. Smith <rms@xyzcorp.com>



your E-mail address in <angle brackets> after your name, like so:

Spaces and punctuation are allowed in the user ID.  It would help if you put

other people using the wrong public key to encrypt messages to you.

use your full name as your user ID, because then there is less risk of

PGP also asks for a user ID, which means your name.  It's a good idea to



the more security you get, but you pay a price in speed.

what size key you want, up to around a thousand bits.  The bigger the key,

(casual grade, commercial grade, or military grade) and prompts you for

specified size.  MacPGP shows you a menu of recommended key sizes

Use this command to generate your own unique public/secret key pair of a



• Generate key...



features.

of PGP and this Macintosh adaptation is its sophisticated key management

hardest part of cryptography.  One of the principal distinguishing features

Since the time of Julius Caesar, key management has always been the




åThe Key Menu