As the summary says. $ git config --get user.signingkey EFB4464E! It is respected for 'git commit -S' but 'git rebase -S' tries to use another key (and fails, in my case). dev-vcs/git-2.6.1-r1::gentoo was built with the following: USE="blksha1 curl gpg iconv mediawiki nls pcre perl python subversion threads webdav -cgi -cvs -doc -emacs -gnome-keyring -gtk -highlight -libressl (-ppcsha1) -test -tk -xinetd" ABI_X86="64" PYTHON_TARGETS="python2_7"
This has been fixed upstream at some point.