hybris repo init error

[HABUILD_SDK] $ repo init -u git://github.com/mer-hybris/android.git -b hybris-15.1
Get https://gerrit.googlesource.com/git-repo/clone.bundle
Get https://gerrit.googlesource.com/git-repo

object 13f323b2c221db4e69e3f5a671455954b65f1fb3
type commit
tag v1.13.2
tagger Mike Frysinger <vapier@google.com> 1547577412 -0500

repo 1.13.2

gpg: Signature made Tue Jan 15 18:36:52 2019 UTC
gpg:                using DSA key 16530D5E920F5C65
gpg: Can't check signature: public key not found


fatal: cloning the git-repo repository failed, will remove '.repo/repo'