Xbase++ Requires Chilkat v11.0.0+

About RSA Public/Private Keys

See more RSA Examples

This example provides some additional information for understanding public/private key pairs. In demonstrates how a private key is a superset of the public key. A public key contains the modulus and exponent. The matching private key also contains the modulus and exponent, but also contains the additional private key parts. Xbase++

LOCAL nSuccess
LOCAL oCert
LOCAL oPubKey
LOCAL oPrivKey

nSuccess := 0

oCert := CreateObject("Chilkat.Cert")

//  Load a digital certificate.
nSuccess := oCert:LoadFromFile("digitalCert.cer")
IF (nSuccess == 0)
    ? oCert:LastErrorText
    oCert:destroy()
    RETURN
ENDIF

//  A .cer file does not contain the private key.  It should contain
//  the public key...
oPubKey := CreateObject("Chilkat.PublicKey")
oCert:GetPublicKey(oPubKey)

//  Let's have a look at it (in XML format).
? "Public Key from Certificate:"
? oPubKey:GetXml()

//  An RSA public key consists of a modulus and exponent.

//  An RSA private key includes both the modulus and exponent,
//  as well as other "big" numbers: P, Q, D, etc.

//  Let's load an RSA private key from a DER-encoded file:
oPrivKey := CreateObject("Chilkat.PrivateKey")

nSuccess := oPrivKey:LoadAnyFormatFile("PrivateKey.key", "")
IF (nSuccess != 1)
    ? oPrivKey:LastErrorText
    oCert:destroy()
    oPubKey:destroy()
    oPrivKey:destroy()
    RETURN
ENDIF

//  If this private key is the matching half to the public key from
//  the certificate, then the modulus and exponent should
//  be identical.  (Thus, a "private key" really contains both the public part as well as the private parts...).
? "Private Key from DER:"
? oPrivKey:GetXml()

oCert:destroy()
oPubKey:destroy()
oPrivKey:destroy()