Xbase++

Get Public Key from CSR

See more CSR Examples

Demonstrates how to get the public key from a CSR. Xbase++

LOCAL nSuccess
LOCAL oPem
LOCAL cNoPassword
LOCAL cStrBase64
LOCAL oAsn
LOCAL oXml
LOCAL cStrModulusHex
LOCAL oBd
LOCAL cModulus64
LOCAL oXmlPubKey
LOCAL oPubkey
LOCAL nPreferPkcs1

nSuccess := 0

//  This requires the Chilkat API to have been previously unlocked.
//  See Global Unlock Sample for sample code.

oPem := CreateObject("Chilkat.Pem")

//  No password is required.  Pass an empty password string..
cNoPassword := ""
nSuccess := oPem:LoadPemFile("qa_data/csr/csr2.pem", cNoPassword)
IF (nSuccess != 1)
    ? oPem:LastErrorText
    oPem:destroy()
    RETURN
ENDIF

cStrBase64 := oPem:GetEncodedItem("csr", "", "base64", 0)

oAsn := CreateObject("Chilkat.Asn")
nSuccess := oAsn:LoadEncoded(cStrBase64, "base64")
IF (nSuccess != 1)
    ? oAsn:LastErrorText
    oPem:destroy()
    oAsn:destroy()
    RETURN
ENDIF

//  Convert the ASN.1 to XML.
oXml := CreateObject("Chilkat.Xml")
nSuccess := oXml:LoadXml(oAsn:AsnToXml())
? oXml:GetXml()
? "----"

cStrModulusHex := oXml:GetChildContent("bits")
? "strModulusHex = " + cStrModulusHex
? "----"

//  We need the modulus as base64.
oBd := CreateObject("Chilkat.BinData")
oBd:AppendEncoded(cStrModulusHex, "hex")
cModulus64 := oBd:GetEncoded("base64")
? "modulus64 = " + cModulus64
? "----"

//  Build the XML for the public key.
oXmlPubKey := CreateObject("Chilkat.Xml")
oXmlPubKey:Tag := "RSAPublicKey"
oXmlPubKey:UpdateChildContent("Modulus", cModulus64)
//  The RSA exponent will always be decimal 65537 (base64 = AQAB)
oXmlPubKey:UpdateChildContent("Exponent", "AQAB")

? "RSA public key as XML:"
? oXmlPubKey:GetXml()
? "----"

//  Load the XML into a Chilkat public key object.
oPubkey := CreateObject("Chilkat.PublicKey")
nSuccess := oPubkey:LoadFromString(oXmlPubKey:GetXml())
IF (nSuccess != 1)
    ? oPubkey:LastErrorText
    oPem:destroy()
    oAsn:destroy()
    oXml:destroy()
    oBd:destroy()
    oXmlPubKey:destroy()
    oPubkey:destroy()
    RETURN
ENDIF

//  Show the public key as PEM.
nPreferPkcs1 := 1
? oPubkey:GetPem(nPreferPkcs1)

oPem:destroy()
oAsn:destroy()
oXml:destroy()
oBd:destroy()
oXmlPubKey:destroy()
oPubkey:destroy()