Tcl

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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Tcl


load ./chilkat.dll

set success 0

#  Load a public key to export.  LoadFromFile inspects the content, so it accepts DER, PEM, XML,
#  JWK, and other supported representations.
set pubKey [new_CkPublicKey]

set success [CkPublicKey_LoadFromFile $pubKey "qa_data/public.pem"]
if {$success == 0} then {
    puts [CkPublicKey_lastErrorText $pubKey]
    delete_CkPublicKey $pubKey
    exit
}

#  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.
set jwk [CkPublicKey_getJwk $pubKey]
if {[CkPublicKey_get_LastMethodSuccess $pubKey] == 0} then {
    puts [CkPublicKey_lastErrorText $pubKey]
    delete_CkPublicKey $pubKey
    exit
}

puts "$jwk"

delete_CkPublicKey $pubKey