Xbase++ Requires Chilkat v11.0.0+

Create a JWS Using ECDSA P-256 SHA-256

See more JSON Web Signatures (JWS) Examples

Creates and validates a JSON Web Signature (JWS) that uses ECDSA P-256 SHA-256 Xbase++

LOCAL nSuccess
LOCAL oSbJwk
LOCAL oEccKey
LOCAL oJwsProtHdr
LOCAL oJws
LOCAL nSignatureIndex
LOCAL nBIncludeBom
LOCAL cPayloadStr
LOCAL cJwsCompact
LOCAL oJws2
LOCAL oEccPubKey
LOCAL v
LOCAL oJoseHeader

nSuccess := 0

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

//  Use the following ECC key loaded from JWK format.
oSbJwk := CreateObject("Chilkat.StringBuilder")
oSbJwk:Append('{"kty":"EC",')
oSbJwk:Append('"crv":"P-256",')
oSbJwk:Append('"x":"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU",')
oSbJwk:Append('"y":"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0",')
oSbJwk:Append('"d":"jpsQnnGQmL-YBIffH1136cspYG6-0iY7X1fCE9-E9LI"')
oSbJwk:Append("}")

oEccKey := CreateObject("Chilkat.PrivateKey")
//  Note: This example loads the ECDSA key from JWK format.  Any format can be loaded
//  into the private key object. (See the online reference documentation..)
nSuccess := oEccKey:LoadJwk(oSbJwk:GetAsString())
IF (nSuccess == 0)
    ? oEccKey:LastErrorText
    oSbJwk:destroy()
    oEccKey:destroy()
    RETURN
ENDIF

//  Create the JWS Protected Header
oJwsProtHdr := CreateObject("Chilkat.JsonObject")
oJwsProtHdr:AppendString("alg", "ES256")

oJws := CreateObject("Chilkat.Jws")

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

//  Set the ECC key:
oJws:SetPrivateKey(nSignatureIndex, oEccKey)

//  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
    oSbJwk:destroy()
    oEccKey:destroy()
    oJwsProtHdr:destroy()
    oJws:destroy()
    RETURN
ENDIF

? "JWS: " + cJwsCompact

//  Note: ECC signatures use random values, so the output will be different each time a signature is produced.
//  sample output:
//  JWS: eyJhbGciOiJFUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.J6EGTNkeuEjehHHBu0SOKzifm8r35wbx49A5964pxzB7gannyZZPMkK7vmlaPJ-K8Xmm8cZsQySAPC12Xd8avw

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

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

oEccPubKey := CreateObject("Chilkat.PublicKey")
oEccKey:ToPublicKey(oEccPubKey)

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

//  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
    oSbJwk:destroy()
    oEccKey:destroy()
    oJwsProtHdr:destroy()
    oJws:destroy()
    oJws2:destroy()
    oEccPubKey:destroy()
    RETURN
ENDIF

IF (v == 0)
    ? "Invalid signature.  The ECC key was incorrect, the JWS was invalid, or both."
    oSbJwk:destroy()
    oEccKey:destroy()
    oJwsProtHdr:destroy()
    oJws:destroy()
    oJws2:destroy()
    oEccPubKey: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")
oJws2:GetProtectedH(nSignatureIndex, oJoseHeader)
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": "ES256"
//  }

oSbJwk:destroy()
oEccKey:destroy()
oJwsProtHdr:destroy()
oJws:destroy()
oJws2:destroy()
oEccPubKey:destroy()
oJoseHeader:destroy()