VerifyChecksum checks that the hash contained in checksumFileName correspond to the hash calculated for filename using hasher.Sum().

VerifyPGPSignature verifies the GPG signature of a file.

VerifySHA512Hash checks that a sidecar file containing a sha512 checksum exists and that the checksum in the sidecar file matches the checksum of the file.

VerifySHA512HashWithCleanup calls VerifySHA512Hash and, in case of a *ChecksumMismatchError, performs a cleanup by deleting both the filename and filename.sha512 files.

ChecksumMismatchError indicates the expected checksum for a file does not match the computed checksum.

InvalidSignatureError indicates the file's GPG signature is invalid.

Downloader is an interface allowing download of an artifact.

Reloader is an interface allowing to reload artifact config.

Verifier is an interface verifying the SHA512 checksum and PGP signature and of a downloaded artifact.