Sunday, March 4, 2007

Digital IDs for Secure Email

Digital ID
A Brief Overview
Digital IDSM A VeriSign White Paper
CONTENTS
What is a Digital ID? 1
What can I do with a Digital ID? 2
How can I get a Digital ID? 3
What is a Digital ID key pair? 4
Why do I need a Digital ID? 5
How do I use Digital IDs? 6
How safe are Digital IDs? 7
How do I protect my Digital ID? 8
How does encryption work? 9
What is public key infrastructure (PKI)? 10
How does client authentication work? 11
How does a digital signature work? 12
How does secure e-mail work? 13
What applications use Digital IDs? 14
How are the keys for a Digital ID managed? 15
What happens when a key expires? 16
What is a hash algorithm? 17
What is a message digest? 18
Glossary 19
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What is a Digital ID?
A Digital ID, sometimes called a digital certificate, is a file on your computer that identifies
who you are. Some software applications use this file to prove your identity to another
person or computer. Here are two common examples:
• When you bank online, your bank must be sure that you are the correct person to get
account information. Like a driver's license or passport, a Digitial ID confirms your
identity to the online bank.
• When you send important e-mail to someone, your e-mail application can use your
Digital ID to "digitally" sign the e-mail message. A digital signature does two things: it
lets the recipient know the e-mail is from you, and it tells them the e-mail was not
tampered with from the time you sent it to the time they received it.
A Digital ID typically contains the following information:
• Your public key (for more information see What is a Digital ID key pair?)
• Your name and e-mail address
• Expiration date of the public key
• Name of the company (the Certification Authority (CA)) who issued your Digital ID
• Serial number of the Digital ID
•.Digital signature of the CA
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What can I do with a Digital ID?
Software applications, networks, and computers can use your Digital ID in several ways:
• Encryption (or data scrambling) is a way of protecting information before sending it
from one computer to another.Typically e-mail applications use the Digital ID that
belongs to the person receiving the encrypted e-mail message. For you to send
someone encrypted messages, you need their public key. See the section on secure email
for more information.
• Client authentication is the term used to describe how you (the client) prove your
identity to somone else or to a computer. For example, online banks need to make sure
you are the correct customer for a given bank account.To prove your identity at the
bank in person, you usually present your driver's license or passport.When online, your
software application presents your Digital ID. Some Web sites might request that you
present your ID before letting you view Web pages that are hidden from others, such as
pages for people who subscribe to a particular service on the Web site.
• A Digital signature, like a hand-written signature, shows that a person created or
otherwise agreed to the document containing the signature. A digital signature actually
provides a greater degree of security than a handwritten signature because the digital
signature verifies both that the message originated from a specific person and that the
message has not been altered either intentionally or accidentally. Furthermore, if you
sign a document, you cannot later disown it by claiming the signature was forged (this
is called nonrepudiation).
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How can I get a Digital ID?
You can aquire a Digital ID from a company called a Certification Authority (CA). Also,
your company or organization might issue you a Digitial ID through the Digital ID Center
in conjunction with a CA.
When your company issues you a Digital ID, they are providing you with a way to identify
yourself to other people in the company, to your company's business partners, or to
computers in your network.
If you are getting a Digital ID for personal reasons, you should seriously consider who you
want to be your CA.When you need to prove your identity, you want a CA that others will
trust. For example, most people and companies trust the validity of a driver's license or
passport.This is because they trust the way the government issues these documents.
However, a student ID is typically accepted as proof of your identity only to the school that
issues the ID.The same holds true for Digital IDs.You want a Digital ID from a CA that is
trusted by all major companies doing business on the Internet.
VeriSign continues to be the leading Certification Authority on the Internet.
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What is a Digital ID key pair?
When you communicate with another person (or computer), you need a way to exchange
information securely, so no one can intercept and read the information. Currently, the most
advanced way to scramble (encrypt) data is through a system that uses key pairs. A key pair
consists of a public and a private key.The keys are used similarly to keys in a lock, except the
key pair requires one key to secure the lock and another to open the lock.
With key pairs, your software application uses one key to encrypt a document.The person
who receives your encrypted document then must use the matching key to decrypt the
message.The problem with this process is how do you give someone the "key" to decrypt
your message without allowing anyone else to get the key?
The solution is in the way the keys are used.When you request a Digital ID, your Web
browser creates both a private key, that can only be used with the Digital ID you requested,
and a public key, that becomes part of the Digital ID.The Web browser might ask you for a
password to use when accessing the private key. It is very important that you choose a
password that only you will know (not your birthday or other number or phrase someone is
likely to guess).
Once you received and installed a Digital ID, you distribute it to whoever needs it.The
Digital ID that you send contains your public key.When someone needs to send you an
encrypted message, they use your public key. Once the message is encrypted with your
public key, you are the only person who can decrypt the message because only you have the
matching private key.
Likewise, when you want to send someone an encrypted message, you must first get their
public key.You do this either by looking up their Digital ID in a directory or you simply
have them send you a signed e-mail message, which contains their Digital ID and public key.
Then your e-mail application can automatically store the Digital ID until you need to use it.
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Why do I need a Digital ID?
Virtual malls, electronic banking, and other electronic services are becoming more
commonplace. However, your concerns about privacy and security might be preventing you
from taking advantage of this new medium for your personal business. A Digital ID can help.
Or, your employer might have a new network that requires you to have a Digital ID for
applications that you use on the job. Because you will use this technology on the job, you
need to learn to use Digital IDs quickly.
Digital IDs are used by Web sites and network applications to scramble data passed between
two computers. Encryption is a powerful tool, but encryption alone is not enough
protection for your information.
Encryption cannot prove your identity or the identity of someone sending you encrypted
information. For example, an online stock broker might have a site that encrypts data sent to
you through its Web pages.The site might even require you to enter a username and
password. However, these types of usernames and passwords are easily intercepted and cannot
be trusted to prove your identity.Without additional safeguards, someone could impersonate
you online and get access to your accounts or other valuable and private information.
Digital IDs address this problem, providing an electronic means of verifying your identity.
Digital IDs provide a more complete security solution, assuring the identity of all parties
involved in a transaction.
Because of the way Digital IDs work, they provide a function called nonrepudiation, which
essentially prevents people from denying that they sent a message. For example, when you
use a credit card, you have to sign a receipt authorizing payment. Because a signature is
required on the receipt, you can prove someone stole or used your card by comparing your
signature to theirs.With nonrepudiation, your "authorization" happens automatically when
you send your Digital ID.
If someone manages to steal your Digital ID, they cannot use it unless they have the
password and your private key.This is why it is critical that you do not tell anyone your
password.
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How do I use Digital IDs?
Once you receive a Digital ID from the Digital ID Center, you need to install it in the
software applications that you use.Typically you install it in your Web browser or your e-mail
application. (See the How To section on the online help for complete instructions.) Once set
up correctly, the applications do most of the work for you, which makes using Digital IDs
fairly easy.
How you use the Digital ID depends on why you need it:
• If you use Web sites or network applications that require your Digital ID, you need to
enter the password for your private key to confirm that you want the application to
send your Digital ID.The application or Web browser takes care of sending your ID to
the Web site or network application. (Of course, this process varies depending on what
application you are using.)
• When sending encrypted (secure) e-mail, you need to retrieve Digital IDs from the
people you communicate with, and then you can configure your e-mail application to
encrypt your messages to those people. Once configured, all e-mail messages to them
are sent encrypted. Some e-mail applications make you select an option each time you
want to encrypt a message.This functionality varies depending on which e-mail product
you use.
• When digitally signing messages, your e-mail application attaches your own Digital ID
to the e-mail message.).
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How safe are Digital IDs?
Digital IDs are very safe provided you keep your private key and password to yourself.Think
of your password as a key to a safe. If you are the only person with the key, the safe's
contents are secure. However, if you share the key with others, you lessen the security of the
safe contents.
If anyone gets your Digital ID, they cannot use it unless they have the matching private key
and the password to the private key. Before your Web browser sends your Digital ID, the
browser prompts you for your password.You must enter the password before your Digital ID
is used.
Digital IDs also come in various strengths.The lowest strength is called "40-bit," which
refers to the size of the key for the ID.The highest strength is called "128-bit." If a 40-bit
key can be deciphered in 4 hours, it would take longer than the age of the universe to crack
a 128-bit key.
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How do I protect my Digital ID?
There are several things you can do to protect your Digital ID:
• Remember your passwords and do not share them with others.
• Protect your computer from unauthorized access by keeping it physically secure. For
example, lock it in an office.When you leave your desk, use a screen saver with a
password or shut down your computer.
• Use access control products or operating system protection features (such as a system
password or password-enabled screen saver).
• Take measures to protect your computer from viruses, because a virus may be able to
attack a private key.
Your private key is protected in two ways:
• When you enroll for a Digital ID, your Web browser creates a private key that is then
stored on your computer's hard drive so you can control access to it.When you
generate your private key, the software you use (such as your browser) will probably ask
you for a password.This password protects access to your private key. For Microsoft
Internet Explorer users, your private key is protected by your Windows password.
• A third party can access your private key only by having access to the file your key is
stored in and by knowing your private-key password. Some software lets you choose to
not have a password to protect your private key. If you use this option, then you are
trusting that no one, presently or in the future, will have unauthorized access to your
computer.
In general, it is far easier to use a password then to completely safeguard your computer
physically. Not using a password is like pre-signing all of the checks in your checkbook and
then leaving it open on your desk.
It is your responsibility to protect your private key.Anyone who obtains your private key can
forge your digital signature and take actions in your name!
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How does encryption work?
Encryption is the process of scrambling data.There are many different (and complicated)
ways to scramble and unscramble information.This section provides a brief description of
encryption without going into too much technical detail.
On the Internet, there are two main uses for encryption. One occurs when you visit a
"secure" Web site, such as an online store or shopping mall.This is called server-side
encryption because it uses the Digital ID given to the server (computer) that runs the Web
site.The other use occurs when you send or receive encrypted e-mail. In both cases, the
encryption process involves exchanging public keys.
When encrypting information, the encryption process is done with either a public or a
private key and then decrypted with the matching public or private key.Think of it as a lock
that requires one key to close the lock and another key to open the lock. For example, when
you visit a secure Web site, your computers receives the Web site's public key.When your
computer sends information to the Web site, your computer encrypts it using the Web site's
public key.The only way to decrypt the information you are sending is with the Web site's
private key.
The same process is needed for secure e-mail. Before you can send someone an encrypted
message, you need their Digital ID, which contains their public key.Your e-mail application
uses their public key to encrypt the message. From that point on, only the recipient's private
key can decrypt the message. So, you can distribute your Digital ID (and its public key) to as
many people as you would like without harming the integrity of your Digital ID. However,
you must guard your private key, since it is used to decrypt any messages sent to you.
There is one more topic of interest: trust. Many different companies (CAs) can create Digital
IDs.Your applications are configured to trust Digital IDs that come from a few highly
reputable companies. So, if someone sends you their Digital ID (either via e-mail or from a
Web site you visit) and it is from a CA that your application does not trust, you will get an
alert message asking if you want to trust the new CA.
For more information on trust, see What is public key infrastructure (PKI)? and What
applications use Digital IDs?.
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What is public key infrastructure (PKI)?
PKI describes a system that uses public keys and Digital IDs to ensure security of the system
and to confirm the identity of its users. For example, a company might use PKI to control
who accesses the company's computer network. In the future, companies might use PKI to
control access to everything from entrance into buildings to procurement of goods.
PKI lets people and companies conduct business in private. Employees can securely send email
over the Internet, without worrying that a competitor could intercept the e-mail.
Companies can build private Web sites, sending information only to known customers.
PKI is based on a system of trust, where two parties (these can be people or computers)
mutually trust a CA to check and confirm the identity of both parties. For example, most
people and companies trust the validity of a driver's license or passport.This is because they
trust the way the government issues these documents. However, a student ID is typically
accepted as proof of your identity only to the school that issues the ID.The same holds true
for Digital IDs.
With PKI, both parties in a transaction (be it an online bank and its customers or an
employer and its employees) agree to trust a CA who issues their Digital IDs.Typically, the
software application that uses your Digital ID has some mechanism for trusting CAs. For
example, a Web browser contains a list of CAs that it trusts.When the Web browser is
presented a Digital ID (say from an online mall doing secure commerce), the browser looks
up the CA who issued the Digital ID. If the CA is in the list of trusted CAs, the browser
accepts the identity of the Web site and displays the web page for you. However, if the CA is
not in the list of trusted CAs, the browser displays a warning message that asks you if you
want to trust the new CA. Usually your browser gives you options for permanantly or
temporarily trusting the CA or not trusting it at all. As a user, you have control over which
CAs you want to trust, but the trust management is done by the software application (in this
example, it is by the Web browser).
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How does client authentication work?
Client authentication describes the process of a computer confirming your identity.The
following example illustrates how a Web site might use client authentication. Client
authentication is not limited to Web sites. Other applications, such as network applications,
can use client authentication, but the process is generally the same.
When you access a Web site that requires a Digital ID, your Web browser presents your
Digital ID to the Web site.The Web site then views information in your ID to determine
what you have permission to do. (Digital IDs used for client authentication are sometimes
called client certificates by Web browsers.)
Depending on your Web browser, you might have to confirm that you want to present your
Digital ID to the Web site. Usually, you will see a dialog box asking for the certificate
password (this is the password for your private key). After you enter the correct password, the
Web browser sends your Digital ID to the Web site.This is why it is important to guard your
password. If someone knows the password for your Digital ID and has access to your
computer, they could easily access your private information or impersonate you online.
Once a Web site views your Digital ID, the site checks the validity of your ID. For example,
the site checks to make sure the ID has not expired.The site might also consider who issued
the Digital ID. If the Web site does not trust the CA who issued you the ID, then you might
be denied access to the site.This is why it is important to use a reputable CA.
The Web site can use any information in the Digital ID when determining what permissions
you have.Your Digital ID might contain some or all of the following information about you:
• Your public key (see What is a Digital ID key?)
• Your name
• Expiration date of the public key
• Name of the company (the CA) who issued your Digital ID
• Serial number of the Digital ID
• Digital signature of the CA
• Various information required by the CA
Once the Web site confirms your identity, it gives you access to the site.
Some Web sites or network applications use the information in your Digital ID to customize
the information you see.This customization is sometimes called access control, but do not
confuse access control for client authenitcation. Client authentication is simply proving your
identity.
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How does a digital signature work?
When you use an application to digitally sign a message, you are basically attaching the
public part of your Digital ID to the message along with other information that ensures the
integrity of your e-mail message.
Before the e-mail message and Digital ID are sent, the message goes through an encoding
process, called a hash algorithm, whereby the message you are sending is used to
mathematically generate a set of characters (letters and numbers) that could only be created
by your exact message.This set of characters is called a message digest.
It is important to know that the hash algorithm works quickly in one direction and is very
difficult to work in reverse.That is, your e-mail application can take your e-mail message,
run it through the hash algorithm, and quickly create a unique message digest. However, if
given just the message digest, it would take years to decipher the e-mail message.
Once the e-mail application creates the message digest, it uses your private key to encrypt
the message digest.This is critical. If you were to send the e-mail and the message digest,
someone could easily change your message text, recreate the message digest, and then send
that along as if it came from you.
Your e-mail application sends the e-mail with the Digital ID and encrypted message digest
as attachments. Note that none of the e-mail message text is sent encrypted. So if someone
wanted to, they could still read the contents of your message.
When someone receives your e-mail message, their application uses your Digital ID (the
public key) to decrypt the message digest.Then the application runs your e-mail text
through the same hash algorithm that your application used. It then compares the results (the
message digests). If the message digests that it created matches the one attached to your email,
then the message text was not tampered with during the transfer from your computer
to theirs.
For more information, see the section on public and private keys.
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How does secure e-mail work?
You can use secure e-mail to do the following:
• Digitally sign a message so that the recipient can verify the message came from you and
not an impostor. Signing a message also ensures the integrity of the message.That is, it
ensures that no one tampered with the message.
• Encrypt a message so that no one can read it while it travels from your computer to
another.
You can set up most e-mail applications to automatically sign or encrypt your messages or
you can manually choose to do it on a case-by-case basis.
For more information, see the Tasks section of the online help.
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What applications use Digital IDs?
Digital IDs are supported by Netscape Navigator 3.0 and higher (on Win 95, NT, Sun
Solaris 2.5x, 2.6, SGI Irix 6.x and HP-UX 10.20) and by Microsoft Internet Explorer 3.02
with authenticode 2.0 update and higher (on Win95 and Win NT 3.5.x or later on x86
platform.)
For signing and encrypting e-mail, Digital IDs are supported by Netscape Messenger,
Microsoft Outlook and Outlook Express, and by any other S/MIME (Secure Multipurpose
Internet Mail Extensions) enabled e-mail application such as Deming, Frontier, Pre-mail,
Opensoft, Connectsoft, and Eudora.
The latest Web browser packages (specifically Netscape Communicator and Microsoft
Internet Explorer), have e-mail applications included (Netscape Messenger and Microsoft
Outlook Express), so Digital IDs obtained through these packages can be used for both email
and the Web. If you are using an e-mail application other than Netscape Messenger or
Microsoft Outlook Express, you should obtain your Digital ID through the e-mail vendor.
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How are the keys for a Digital ID managed?
Users must be able to securely obtain your Digital ID so they can send you encrypted email.
Likewise, you need a way to look up their Digital IDs.You can send a digitally signed
e-mail message to the people you want to send you encrypted messages. And you can have
them send you signed messages so you can get their Digital IDs.You can also look up Digital
IDs in various directories.
The Digital ID Center contains a search feature that lets you find Digital IDs that belong to
you and to other people in your organization.
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What happens when a key expires?
In order to guard against a brute-force attack, every key must have an expiration date after
which it is no longer valid.
The expiration date is stored in the public key of a Digital ID. Every Web browser or e-mail
application checks the validity of a Digital ID by making sure the date you receive the
Digital ID (and the information it is protecting) is within the valid dates.This means that
when your own key expires, everything you signed with it will no longer be valid.
After expiration, the you need to renew your Digital ID using the Digital ID Center.
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What is a hash algorithm?
A hash function is a math equation that uses text (such as an e-mail message) to create a
code called a message digest. Examples of well-known hash functions are MD4, MD5, and
SHS.
A hash function used for digital authentication must have certain properties that make it
secure enough for cryptographic use. Specifically, it must be infeasible to find:
• Text that hashes to a given value.That is, if you know the message digest, you should
not be able to figure out the message.
• Two distinct messages that hash to the same value
The ability to find a message that hashes to a given value would enable an attacker to
substitute a fake message for a real message that was signed. It would also enable someone to
falsely disown a message by claiming that he or she actually signed a different message
hashing to the same value, thus violating the non-repudiation property of digital signatures.
The ability to find two distinct messages that hash to the same value could enable an attack
whereby someone is tricked into signing a message that hashes to the same value as another
message with a quite different meaning.
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What is a message digest?
A message digest is the results you get when you run text (such as an e-mail message)
through a hash algorithm. A message digest concisely represents a longer message or
document.You can think of a message digest as the "digital fingerprint" of a larger
document. A message digest is used to create a digital signature that's unique to a particular
document.
A message digest does not reveal the contents of a document.That is, if you can view the
message digest, you cannot figure out what the original message was.
MD2, MD4 and MD5 (MD stands for Message Digest) are widely used hash functions
designed specifically for cryptographic use.They produce 128-bit digests and there is no
known attack faster than exhaustive search.
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Glossary
CERT.DB FILE
This file contains your Digital ID for Netscape Navigator or Communicator.
CERTIFICATE (PUBLIC KEY CERTIFICATE)
Certificate is another word for Digital ID. Some software applications and Web browsers
use this term.
CHALLENGE PHRASE
A set of numbers and/or letters chosen by a Digital ID applicant, and used to
authenticate the subscriber for various actions such as the Digital ID revocation,
replacement, and renewal.
CRYPTOGRAPHY (Cf.,PUBLIC KEY CRYPTOGRAPHY)
The mathematical science used to secure the confidentiality and authentication of data
by transforming data in order to hide its information content, prevent undetected
modification, and/or prevent unauthorized use.
DIGITAL ID EXPIRATION
A time and date specified in the Digital ID when the operational period ends.
DIGITAL ID HIERARCHY
A structure of Digital IDs which allows individuals to verify the validity of a Digital
ID's issuer. Digital IDs are issued and signed by Digital IDs which reside higher in the
Digital ID hierarchy.The validity of a given Digital ID is determined by the
corresponding validity of the Digital ID which signed it.
DIGITAL ID SERIAL NUMBER
A value that unambiguously identifies a Digital ID issued by a Certification Authority.
DIGITAL SIGNATURE
A method to validate that a specific message was not altered during transmission.This
process involves creating a message, encrypting it, and sending both the original message
and the encrypted message together. Once received, the recipient compares the contents
of the original message against the contents of the encrypted message to make sure the
information has not been changed.
DISTINGUISHED NAME
The set of data used to identify an individual Digital ID holder.Within a Class 1 Digital
ID this would be information such as your Name and your e-mail address, and the
issuer of the Digital ID (VeriSign, Inc.).
DOMESTIC RELEASE BROWSER
Available to US and Canadian browser customers only.This browser supports "strong"
encryption at the 128-bit level.You can only download this type of browser if you live
in the United States or Canada.
ENCRYPTION
The process of scrambling information so that only the intended recipient can
unscramble and read the information.
ENROLLMENT
The process of applying for a Digital ID.
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EXPORT
The process of backing up a Digital ID to avoid loss. Digital IDs contain information
you cannot recover in the event of a hard drive crash or browser re-installation, so you
should make a copy and store it in a secure place.
GENERATE A KEY PAIR
The process of creating a private key during Digital ID application whose
corresponding public key is submitted to VeriSign for validation. (See also PUBLIC
KEY CRYPTOGRAPHY; PUBLIC KEY and PRIVATE KEY)
INTERNATIONAL RELEASE BROWSER
Available worldwide, supporting maximum key sizes of 512 bits and 40 bit session keys.
Higher encryption available to US and Canadian citizens by filing a eligibility
declaration on the browser vendor's web site and downloading the application.
KEY GENERATION
The process of creating a private key during Digital ID enrollment whose
corresponding public key is submitted to the Digital ID Center for validation.
KEY PAIR
A key pair consists of a private key and a corresponding public key.The private key,
typically protected by a password and stored on your computer, is known only to you
and is not sent to anyone.The public key is shared with other people and computers or
web sites.
LIGHTWIEIGHT DIRECTORY ACCESS PROTOCOL (LDAP)
The Lightweight Directory Access Protocol (LDAP) is a protocol for accessing online
directory services that might contain other user's Digital IDs.
OPERATIONAL PERIOD
The period starting with the date and time a Digital ID is issued and ending with the
date and time on which the Digital ID expires or is earlier suspended or revoked.
PASSWORD
Confidential authentication information, usually composed of a string of characters used
to provide access to the private key of your Digital ID.
PIN NUMBER
The PIN number is used only once--during Digital ID retrieval. It consists of 32
characters using the letters A-F and the numbers 0-9.There are no spaces before, after
or in the PIN number.
PKCS #12
A standard that specifies a portable format for storing or transporting a user's private
keys and Digital IDs.
PRIVATE KEY
A mathematical key (kept secret by the holder) used to create digital signatures and,
depending upon the algorithm, to decrypt messages or files encrypted (for
confidentiality) with the corresponding public key.
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PUBLIC KEY
A mathematical key that can be shared safely so that others can send you encrypted
information that only your private key can unscramble.The public key can also verify
signatures created with its corresponding private key. Depending on the algorithm,
public keys are also used to encrypt messages or files that can then be decrypted with
the corresponding private key.
PUBLIC KEY CRYPTOGRAPHY
A type of cryptography that uses a key pair of mathematically related cryptographic
keys.The public key can be made available to anyone who wishes to use it and can
encrypt information or verify a digital signature; the private key is kept secret by its
holder and can decrypt information or generate a digital signature.
.P12 FILE
The file extension assigned to all Digital IDs exported from Netscape Communicator
using the PKCS #12 standard.
.PFX FILE
The file extension assigned to all Digital IDs exported from Microsoft Internet
Explorer using the PKCS #12 standard.
RECIPIENT (of a DIGITAL SIGNATURE)
A person who receives a digital signature and who is in a position to rely on it, whether
or not such reliance occurs.
RELYING PARTY
A recipient who accepts a Digital ID and digital signature, such as an online bank or ecommerce
company.
RENEW A DIGITAL ID
The process of obtaining a new Digital ID once an existing Digital ID has expired.
REPLACE A DIGITAL ID
The process of obtaining a replacement Digital ID once an existing Digital ID has been
revoked.
RETRIEVE A DIGITAL ID
The process of picking up a pending Digital ID after the enrollment form is completed.
When the Digital ID is picked up, it is considered issued.
REVOKE A DIGITAL ID
The process of permanently ending the valid period of a Digital ID. Someone must use
the Digital ID Center to determine if a Digital ID has been revoked.
RSA
A public key cryptographic system invented by Rivest, Shamir & Adelman. For more
information visit their Web site: www.rsa.com
SECURE CHANNEL
This refers to information sent encrypted over the network. For example, you purchase
items from a web site using a secure (encrypted) channel.
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SESSION KEY
The key size assigned for a secured communication between a client and server using
SSL (Secure Sockets Layer). Depending on the use of International or Domestic
browsing software the session will be assigned an 40 or 128 bit encryption session.
SIGNER
A person who creates a digital signature for a message or a signature for a document.
S/MIME
A specification for secure e-mail that uses a cryptographic message syntax in an Internet
MIME (multipurpose internet message exchange) environment.
SUBSCRIBER
A person who has been issued a Digital ID and is capable of using the private key that
corresponds to the public key listed in the Digital ID.
SUBSCRIBER AGREEMENT
The agreement executed between a subscriber and VeriSign for the provision of
designated public certification services in accordance with the CPS.
SUBSCRIBER INFORMATION
Information supplied to a certification authority as part of a Digital ID application.
TRUSTED THIRD PARTY
In general, an independent, unbiased third party that contributes to the ultimate
security and trustworthiness of computer-based information transfers, such as VeriSign.
UNIFORM RESOURCE LOCATOR (URL)
A standardized device for identifying and locating certain records and other resources
located on the World Wide Web. Most URLs appear in the familiar form of Web site
addresses such as .
VALIDATE A DIGITAL ID
The process performed by a recipient or relying party to confirm that an end-user
Digital ID is valid and was operational at the date and time a pertinent digital signature
was created.
VERIFY (A DIGITAL SIGNATURE)
The process of determining accurately that a digital signature was created during the
operational period of a valid Digital ID and the associated message was not altered since
the digital signature was created.
WORLD WIDE WEB (WWW)
A hypertext-based, distributed information system in which users may create, edit, or
browse hypertext documents. A graphical document publishing and retrieval medium; a
collection of linked documents that reside on the Internet.
X.509
The ITU-T (International Telecommunications Union-T) standard for Digital IDs.
X.509 v3 refers to Digital IDs containing or capable of containing extensions.
©2004 VeriSign, Inc. All rights reserved.
VeriSign, the VeriSign logo, NetSure, and other trademarks, service marks, and logos are registered or unregistered trademarks of VeriSign and its subsidiaries in the United States and other
countries. All other trademarks belong to their respective owners. 1/04

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