Xbase++ Requires Chilkat v11.0.0+

Validate a JWS Using ECDSA P-256 SHA-256

See more JSON Web Signatures (JWS) Examples

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

LOCAL nSuccess
LOCAL oSbPubKey
LOCAL oPubKey
LOCAL oJws
LOCAL nSignatureIndex
LOCAL oSbJws
LOCAL v
LOCAL oJoseHeader

nSuccess := 0

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

//  This example takes a JSON signature in compact serialization format,
//  and uses an ECDSA public key to validate and recover the protected header and payload.

//  We only need a public key for signature validation.  This is the ECDSA public key
//  that is used:

//       {"kty":"EC", 
//        "crv":"P-256", 
//        "x":"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU", 
//        "y":"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0" 
//       } 

oSbPubKey := CreateObject("Chilkat.StringBuilder")
oSbPubKey:Append('{"kty":"EC",')
oSbPubKey:Append('"crv":"P-256",')
oSbPubKey:Append('"x":"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU",')
oSbPubKey:Append('"y":"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0"')
oSbPubKey:Append("}")

oPubKey := CreateObject("Chilkat.PublicKey")
nSuccess := oPubKey:LoadFromString(oSbPubKey:GetAsString())
IF (nSuccess == 0)
    ? oPubKey:LastErrorText
    oSbPubKey:destroy()
    oPubKey:destroy()
    RETURN
ENDIF

oJws := CreateObject("Chilkat.Jws")

//  Set the ECC public key:
nSignatureIndex := 0
oJws:SetPublicKey(nSignatureIndex, oPubKey)

//  Load the JWS.
oSbJws := CreateObject("Chilkat.StringBuilder")
oSbJws:Append("eyJhbGciOiJFUzI1NiJ9")
oSbJws:Append(".")
oSbJws:Append("eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFt")
oSbJws:Append("cGxlLmNvbS9pc19yb290Ijp0cnVlfQ")
oSbJws:Append(".")
oSbJws:Append("DtEhU3ljbEg8L38VWAfUAqOyKAM6-Xx-F4GawxaepmXFCgfTjDxw5djxLa8ISlSA")
oSbJws:Append("pmWQxfKTUJqPP3-Kg6NU1Q")

nSuccess := oJws:LoadJwsSb(oSbJws)
IF (nSuccess == 0)
    ? oJws:LastErrorText
    oSbPubKey:destroy()
    oPubKey:destroy()
    oJws:destroy()
    oSbJws:destroy()
    RETURN
ENDIF

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

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

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

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

//  Examine the protected header:

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

oJoseHeader:EmitCompact := 0

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

//  Output:

//  	Signature validated.
//  	--
//  	Recovered content:
//  	{"iss":"joe",
//  	 "exp":1300819380,
//  	 "http://example.com/is_root":true}
//  	--
//  	Protected (JOSE) header:
//  	{ 
//  	  "alg": "ES256"
//  	}

oSbPubKey:destroy()
oPubKey:destroy()
oJws:destroy()
oSbJws:destroy()
oJoseHeader:destroy()