Imports github.com/unidoc/unipdf/v3/annotator github.com/unidoc/unipdf/v3/core github.com/unidoc/unipdf/v3/model github.com/unidoc/unipdf/v3/model/sighandler Standard library imports crypto/rand crypto/rsa crypto/x509 crypto/x509/pkix fmt log math/big os time