certificateSha1Thumbprint
The "x5t" (X.509 certificate SHA-1 thumbprint) Header Parameter is a base64url-encoded SHA-1 thumbprint (a.k.a. digest) of the DER encoding of the X.509 certificate (RFC5280) corresponding to the key used to digitally sign the JWS. Note that certificate thumbprints are also sometimes known as certificate fingerprints. Use of this Header Parameter is OPTIONAL.