B4X

Create a JWS into a StringBuilder

See more JSON Web Signatures (JWS) Examples

Demonstrates Jws.CreateJwsSb, which creates a JWS and writes it into a StringBuilder.

Background. JWS (JSON Web Signature) integrity-protects a payload with a signature or MAC. The header alg names the algorithm; this example uses HMAC-SHA256 (HS256) with a symmetric MAC key.

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Dim success As Boolean = False

Dim jws As ChilkatJws
jws.Initialize

'  Set the protected header for signer 0, specifying the signature algorithm (alg).
Dim header As ChilkatJsonObject
header.Initialize
header.UpdateString("alg", "HS256")
success = jws.SetProtectedHeader(0, header)
If success = False Then
    Log(jws.LastErrorText)
    Return
End If


'  Set the payload to be signed.
Dim bIncludeBom As Boolean = False
success = jws.SetPayload("This is the content to sign.", "utf-8", bIncludeBom)
If success = False Then
    Log(jws.LastErrorText)
    Return
End If


'  Provide the HMAC key (base64) for signer 0.  In production, obtain the key from a secure source
'  rather than hard-coding it.
Dim base64Key As String = "YWJjZGVmZ2hpamtsbW5vcHFyc3R1dnd4eXowMTIzNDU="
success = jws.SetMacKey(0, base64Key, "base64")
If success = False Then
    Log(jws.LastErrorText)
    Return
End If


'  Create the JWS and write it into a StringBuilder.
Dim sbJws As ChilkatStringBuilder
sbJws.Initialize
success = jws.CreateJwsSb(sbJws)
If success = False Then
    Log(jws.LastErrorText)
    Return
End If

Log(sbJws.GetAsString)