Xbase++ Requires Chilkat v11.5.0+

Create JWS Using Private Key on a Smart Card

See more JSON Web Signatures (JWS) Examples

Creates and validates a JSON Web Signature (JWS) using the private key associated with a certificate on a smart card. Xbase++

LOCAL nSuccess
LOCAL oCert
LOCAL oJwsProtHdr
LOCAL oJws
LOCAL nSignatureIndex
LOCAL nBIncludeBom
LOCAL cPayloadStr
LOCAL cJwsCompact
LOCAL oJws2
LOCAL oPubKey
LOCAL v
LOCAL oJoseHeader

nSuccess := 0

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

//  Load the certificate from a smart card.
oCert := CreateObject("Chilkat.Cert")

//  Set the smarcard PIN prior to loading
oCert:SmartCardPin := "123456"

//  Detect the connected smartcard or USB security token and load the default certificate.
nSuccess := oCert:LoadFromSmartcard("")
IF (nSuccess == 0)
    ? oCert:LastErrorText
    oCert:destroy()
    RETURN
ENDIF

//  Note: Chilkat provides many different ways to load a certificate from a smartcard or USB token,
//  such as selecting a certificate if the card contains multiple certificates with private keys,
//  or working with lower-level PKCS11 or ScMinidriver API's (both of which Chilkat provides).

//  Create the JWS Protected Header
oJwsProtHdr := CreateObject("Chilkat.JsonObject")

IF (oCert:IsEcdsa() == 1)
    oJwsProtHdr:AppendString("alg", "ES256")
ELSE
    oJwsProtHdr:AppendString("alg", "RS256")
ENDIF

oJws := CreateObject("Chilkat.Jws")

//  Set the protected header:
nSignatureIndex := 0
oJws:SetProtectedHeader(nSignatureIndex, oJwsProtHdr)

//  Provide the private key via the certificate.
//  This requires Chilkat v11.5.0 or greater.
oJws:SetSigningCert(nSignatureIndex, oCert)

//  Set the payload.
nBIncludeBom := 0
cPayloadStr := "In our village, folks say God crumbles up the old moon into stars."
oJws:SetPayload(cPayloadStr, "utf-8", nBIncludeBom)

//  Create the JWS
//  By default, the compact serialization is used.
cJwsCompact := oJws:CreateJws()
IF (oJws:LastMethodSuccess == 0)
    ? oJws:LastErrorText
    oCert:destroy()
    oJwsProtHdr:destroy()
    oJws:destroy()
    RETURN
ENDIF

? "JWS: " + cJwsCompact

//  sample output:
//  JWS: eyJhbGciOiJQUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.TRWhwRo5dMv9-8OzrInfJTwmUGYgjLfHk8lqF072ND-FmLWEBnUTOpY8oJXp8FdWw2SalbdOeNlrtlJjwk4XK8Ql2iJ_2qMCtxsvLPhKBOqFoAF4aBvTOEDVJDxf0DaBSiydEEtfTVV2iwBcjWabu5J2XieR5y7QZQtuHsn7T3qKBvCcCejN3Y2oqAT3qMHvu1fTms1r_91wBn_K7Wjd9UkZ1n02qQcUHJznR_OF2BgN7_KWIDAF9ZS9keoju2NPpPelO4yxa2XUPnehY3G7dHKoCxUEQR4d2Xc5voqDASTVCDqQS4PVOZdvT3Ein6-SanAlCwbWBbkvT8g6-5PImQ

//  Now load the JWS, validate, and recover the original text.
oJws2 := CreateObject("Chilkat.Jws")

//  Load the JWS.
nSuccess := oJws2:LoadJws(cJwsCompact)

oPubKey := CreateObject("Chilkat.PublicKey")
oCert:GetPublicKey(oPubKey)

//  Set the public key used for validation.
nSignatureIndex := 0
oJws2:SetPublicKey(nSignatureIndex, oPubKey)

//  Validate the 1st (and only) signature at index 0..
v := oJws2:Validate(nSignatureIndex)
IF (v < 0)
    //  Perhaps Chilkat was not unlocked or the trial expired..
    ? "Method call failed for some other reason."
    ? oJws2:LastErrorText
    oCert:destroy()
    oJwsProtHdr:destroy()
    oJws:destroy()
    oJws2:destroy()
    oPubKey:destroy()
    RETURN
ENDIF

IF (v == 0)
    ? "Invalid signature.  The key was incorrect, the JWS was invalid, or both."
    oCert:destroy()
    oJwsProtHdr:destroy()
    oJws:destroy()
    oJws2:destroy()
    oPubKey:destroy()
    RETURN
ENDIF

//  If we get here, the signature was validated..
? "Signature validated."

//  Recover the original content:
? oJws2:GetPayload("utf-8")

//  Examine the protected header:

oJoseHeader := CreateObject("Chilkat.JsonObject")
nSuccess := oJws2:GetProtectedH(nSignatureIndex, oJoseHeader)
IF (nSuccess == 0)
    ? oJws2:LastErrorText
    oCert:destroy()
    oJwsProtHdr:destroy()
    oJws:destroy()
    oJws2:destroy()
    oPubKey:destroy()
    oJoseHeader:destroy()
    RETURN
ENDIF

oJoseHeader:EmitCompact := 0

? "Protected (JOSE) header:"
? oJoseHeader:Emit()

//  Output:

//  	Signature validated.
//  	In our village, folks say God crumbles up the old moon into stars.
//  	Protected (JOSE) header:
//  	{ 
//  	  "alg": "RS256"
//  	}

oCert:destroy()
oJwsProtHdr:destroy()
oJws:destroy()
oJws2:destroy()
oPubKey:destroy()
oJoseHeader:destroy()