SHA2 checksum for Sierra's InstallESD.dmg?
A comprehensive list of sha1 checksums of the InstallESD.dmg (or similar files) in various OS X/macOS installer apps is available here: Mac OSX Installers SHA1 Checksums.

The sha2 checksum of the InstallESD.dmg of macOS Sierra 10.12.0 is indeed: 78a2701bb63a0dcb30862314d1a4598522cfe6a2dd2b096a4e30f256909a4446