in pkg/internal/pop/authnscheme.go [136:150]
func createPoPAccessToken(h header, p payload, popKey PoPKey) (*popAccessToken, error) {
token := &popAccessToken{
Header: h,
Payload: p,
}
h256 := sha256.Sum256([]byte(h.ToBase64() + "." + p.ToBase64()))
sig, err := popKey.Sign(h256[:])
if err != nil {
return nil, err
}
token.Signature = signature{
sig: sig,
}
return token, nil
}