似乎 16.04 之前的安全密钥安全性已不再足够。我不确定该怎么做才能解决这个问题。或者这是谷歌需要解决的问题？
moorepants@parvati:~$ sudo aptitude update
Hit http://mirror.math.ucdavis.edu/ubuntu xenial InRelease
Hit http://mirror.math.ucdavis.edu/ubuntu xenial-updates InRelease
Hit http://mirror.math.ucdavis.edu/ubuntu xenial-backports InRelease
Hit http://mirror.math.ucdavis.edu/ubuntu xenial-security InRelease
Ign http://dl.google.com/linux/chrome/deb stable InRelease
Ign http://dl.google.com/linux/musicmanager/deb stable InRelease
Hit http://dl.google.com/linux/chrome/deb stable Release
Get: 1 http://dl.google.com/linux/musicmanager/deb stable Release [1,345 B]
Hit http://archive.canonical.com/ubuntu wily InRelease
Hit http://ppa.launchpad.net/system76-dev/stable/ubuntu xenial InRelease
Get: 2 http://dl.google.com/linux/musicmanager/deb stable Release.gpg [198 B]
Fetched 1,543 B in 0s (2,637 B/s)
W: http://dl.google.com/linux/chrome/deb/dists/stable/Release.gpg: Signature by key <KEY> uses weak digest algorithm (SHA1)
W: http://dl.google.com/linux/musicmanager/deb/dists/stable/Release.gpg: Signature by key <KEY> uses weak digest algorithm (SHA1)
W: Failed to fetch http://dl.google.com/linux/musicmanager/deb/dists/stable/Release: No Hash entry in Release file /var/lib/apt/lists/partial/dl.google.com_linux_musicmanager_deb_dists_stable_Release which is considered strong enough for security purposes
E: Some index files failed to download. They have been ignored, or old ones used instead.