Certificate chain and Certificate

[Q] How to get the whole certificate chain from a given X509 certificate?
[Q] How to get the CA's certificate from a given DN?
[Q] How to get the CA's certificate from a given public key?

[try]
C#,
X509Chain xChain;
X509Certificate2 cert;
...
xChain.Build(cert);
...
X509ChainElement
...

[ref]
X509Chain,
http://msdn.microsoft.com/en-us/library/system.security.cryptography.x509certificates.x509chain.aspx

online certificate chain check,
http://forums.asp.net/t/1149495.aspx

//===

• certificate chain = certificate path
• DN= Distinguished Name
• CN= Common Name

//=== Digital certificate (or Certificate for short)

Digital certificates are used to authenticate an entity( a person, an organization, a company, ...) 
 by  "a chain of trust" .
 
The chain is formed topdown?,  with a root authority(RA) at the top.
To view any certificate's chain,

• trigger MMC snap-in by double-clicking a certificate,
• then click the Certificate Path tab.

//===
The root authority certificate at the top of a certificate chain is self-issued.

//===  Distinguished Name (DN) uniquely identifies an entity in an X.509 certificate.
Attribute types in  DN:

• CN:  Common Name
•  T :  Title
•  O :  Organization name
•  OU :  Organizational Unit name
•  L : Locality name
•  ST (or SP or S)  : State or Province name
•  C : Country

 //=== Digital certificate (Certificate for short)

A digital certificate contain at least the following information

• The owner's public key
• The owner's Distinguished Name  (Owner's DN)
• The Distinguished Name of the CA that is issuing the certificate (issuer's DN)
• The date from which the certificate is valid (Valid From)
• The expiry date of the certificate (Valid To)
• A version number
• A serial number (SN)

 
[ref]
http://publib.boulder.ibm.com/infocenter/iseries/v5r3/index.jsp?topic=/rzahu/rzahudistname.htm

http://java.sun.com/j2se/1.5.0/docs/guide/security/cert3.html

http://www.iona.com/support/docs/orbix2000/2.0/tls/html/OpenSSL4.html