PureBasic Requires Chilkat v11.0.0+

JWS Using HMAC SHA-256

See more JSON Web Signatures (JWS) Examples

Creates a JSON Web Signatures (JWS) using HMAC SHA-256. PureBasic

IncludeFile "CkJws.pb"
IncludeFile "CkJsonObject.pb"

Procedure ChilkatExample()

    success.i = 0

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

    ;  First create the JWS Protected Header
    jwsProtHdr.i = CkJsonObject::ckCreate()
    If jwsProtHdr.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkJsonObject::ckAppendString(jwsProtHdr,"typ","JWT")
    CkJsonObject::ckAppendString(jwsProtHdr,"alg","HS256")
    Debug "JWS Protected Header: " + CkJsonObject::ckEmit(jwsProtHdr)

    ;  Output:
    ;  JWS Protected Header: {"typ":"JWT","alg":"HS256"}

    jws.i = CkJws::ckCreate()
    If jws.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Set the HMAC key:
    hmacKey.s = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow"
    signatureIndex.i = 0
    CkJws::ckSetMacKey(jws,signatureIndex,hmacKey,"base64url")

    ;  Set the protected header:
    CkJws::ckSetProtectedHeader(jws,signatureIndex,jwsProtHdr)

    ;  Set the payload.
    bIncludeBom.i = 0
    payloadStr.s = "In our village, folks say God crumbles up the old moon into stars."
    CkJws::ckSetPayload(jws,payloadStr,"utf-8",bIncludeBom)

    ;  Create the JWS
    ;  By default, the compact serialization is used.
    jwsCompact.s = CkJws::ckCreateJws(jws)
    If CkJws::ckLastMethodSuccess(jws) = 0
        Debug CkJws::ckLastErrorText(jws)
        CkJsonObject::ckDispose(jwsProtHdr)
        CkJws::ckDispose(jws)
        ProcedureReturn
    EndIf

    Debug "JWS: " + jwsCompact

    ;  sample output:
    ;  JWS: eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.bsYsi8HJ0N6OqGI1hKQ9QQRNPxxA5qMpcHLtOvXatk8

    ;  Now load the JWS, validate, and recover the original text.
    jws2.i = CkJws::ckCreate()
    If jws2.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ;  Load the JWS.
    success = CkJws::ckLoadJws(jws2,jwsCompact)

    ;  Set the MAC key used for validation.
    signatureIndex = 0
    CkJws::ckSetMacKey(jws2,signatureIndex,hmacKey,"base64url")

    ;  Validate the 1st (and only) signature at index 0..
    v.i = CkJws::ckValidate(jws2,signatureIndex)
    If v < 0
        ;  Perhaps Chilkat was not unlocked or the trial expired..
        Debug "Method call failed for some other reason."
        Debug CkJws::ckLastErrorText(jws2)
        CkJsonObject::ckDispose(jwsProtHdr)
        CkJws::ckDispose(jws)
        CkJws::ckDispose(jws2)
        ProcedureReturn
    EndIf

    If v = 0
        Debug "Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both."
        CkJsonObject::ckDispose(jwsProtHdr)
        CkJws::ckDispose(jws)
        CkJws::ckDispose(jws2)
        ProcedureReturn
    EndIf

    ;  If we get here, the signature was validated..
    Debug "Signature validated."

    ;  Recover the original content:
    Debug CkJws::ckGetPayload(jws2,"utf-8")

    ;  Examine the protected header:

    joseHeader.i = CkJsonObject::ckCreate()
    If joseHeader.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkJws::ckGetProtectedH(jws2,signatureIndex,joseHeader)
    If success = 0
        Debug CkJws::ckLastErrorText(jws2)
        CkJsonObject::ckDispose(jwsProtHdr)
        CkJws::ckDispose(jws)
        CkJws::ckDispose(jws2)
        CkJsonObject::ckDispose(joseHeader)
        ProcedureReturn
    EndIf

    CkJsonObject::setCkEmitCompact(joseHeader, 0)

    Debug "Protected (JOSE) header:"
    Debug CkJsonObject::ckEmit(joseHeader)

    ;  Output:

    ;  	Signature validated.
    ;  	In our village, folks say God crumbles up the old moon into stars.
    ;  	Protected (JOSE) header:
    ;  	{ 
    ;  	  "typ": "JWT",
    ;  	  "alg": "HS256"
    ;  	} 


    CkJsonObject::ckDispose(jwsProtHdr)
    CkJws::ckDispose(jws)
    CkJws::ckDispose(jws2)
    CkJsonObject::ckDispose(joseHeader)


    ProcedureReturn
EndProcedure