Blackbox on GitLab CI, unable to load GPG private key

I'm trying to use Blackbox to encrypt sensitive files in a repository I'm working with, but I am unable to make the GitLab CI pipeline load the private GPG key required to decrypt the files. At the , you can see the output from the GitLab CI runner where it is evident that: - My private key, stored as a Secret Variable for the runner, is available. - The secret key is properly written to a file that can be read back. - The GPG key is properly formatted and contains a complete and proper key. - GPG exists and can be properly initiated. However, when I run the command `gpg -v --import /tmp/server.gpg`, I keep getting `gpg: no valid OpenPGP data found.`. This makes no sense. I have followed all posts I could find on this, but they are either about verifying file contents rather than actually importing a proper key, or that the key is actually malformed, which mine evidently is not. I'd appreciate any help I can get on this matter as I am making no progress whatsoever. Thank you! Output from the GitLab CI runner: ``` Running with gitlab-ci-multi-runner 9.1.0 (0118d89) on docker-auto-scale (e11ae361) Using Docker executor with image golang:1.8.1 ... Using docker image sha256:3858bc6d4732445082339c9ccccfe56bf599d1fe7d9e850fb67ceec76807ed8d for predefined container... Pulling docker image golang:1.8.1 ... Using docker image golang:1.8.1 ID=sha256:6d0bfafa0452c6398be979f89614b5e3cb5d10e853ccd4f5791c4971a88065e0 for build container... Running on runner-e11ae361-project-3172553-concurrent-0 via runner-e11ae361-machine-1493644095-36064084-digital-ocean-2gb... Cloning repository... Cloning into '/builds/project/repo'... Checking out 7013b30a as feature/blackbox... Skipping Git submodules setup $ git clone https://github.com/StackExchange/blackbox Cloning into 'blackbox'... $ cd blackbox $ make manual-install Symlinking files from ./bin to /usr/local/bin Done. $ echo $GPG_PRIVATE_KEY > /tmp/server.gpg $ chmod 400 /tmp/server.gpg $ cat /tmp/server.gpg -----BEGIN PGP PRIVATE KEY BLOCK----- Version: GnuPG v2 [redacted] -----END PGP PRIVATE KEY BLOCK----- $ gpg -v --list-keys gpg: directory `/root/.gnupg' created gpg: new configuration file `/root/.gnupg/gpg.conf' created gpg: WARNING: options in `/root/.gnupg/gpg.conf' are not yet active during this run gpg: keyring `/root/.gnupg/pubring.gpg' created gpg: /root/.gnupg/trustdb.gpg: trustdb created gpg: using PGP trust model $ gpg -v --import /tmp/server.gpg gpg: keyring `/root/.gnupg/secring.gpg' created gpg: no valid OpenPGP data found. gpg: Total number processed: 0 ERROR: Job failed: exit code 1 ```