B4X

Export a Public Key as a JWK

Demonstrates the Chilkat PublicKey.GetJwk method, which returns the public key as a compact JWK (JSON Web Key). It takes no arguments; binary values use Base64url without padding and the member order is stable across calls.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: JWK is the JSON key format used across modern web security — JWT, OAuth, OpenID Connect. Exporting a public key to JWK is exactly what you do to publish it in a JWK Set (a jwks_uri endpoint) so others can verify your signatures. The stable member order matters because it makes the output reproducible, which is important when the JWK feeds into a thumbprint.

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Dim success As Boolean = False

'  Load a public key to export.  LoadFromFile inspects the content, so it accepts DER, PEM, XML,
'  JWK, and other supported representations.
Dim pubKey As ChilkatPublicKey
pubKey.Initialize
success = pubKey.LoadFromFile("qa_data/public.pem")
If success = False Then
    Log(pubKey.LastErrorText)
    Return
End If


'  Export the public key as a compact JWK (JSON Web Key).  Binary values use Base64url without
'  padding, and the member order is stable across calls.
Dim jwk As String = pubKey.GetJwk
If pubKey.LastMethodSuccess = False Then
    Log(pubKey.LastErrorText)
    Return
End If

Log(jwk)