为什么Git需要签名推送？

在发行说明的Git 2.2.0,它描述了一个新的选择git push,--signed:

"git push" learned "--signed" push, that allows a push (i.e.
request to update the refs on the other side to point at a new
history, together with the transmission of necessary objects) to be
signed, so that it can be verified and audited, using the GPG
signature of the person who pushed, that the tips of branches at a
public repository really point the commits the pusher wanted to,
without having to "trust" the server.

因此,这听起来像是在推送期间发送到服务器的数据被签名,以便服务器可以验证并记录谁进行了推送.在man页面中,您可以确认:

--signed
   GPG-sign the push request to update refs on the receiving side, 
   to allow it to be checked by the hooks and/or be logged. See 
   git-receive-pack[1] for the details on the receiving end.

您查看under 和hooks 的man页面,git-receive-pack以确切了解如何验证签名推送.pre-receivepost-recieve

似乎所有这些都有助于服务器验证谁正在进行推送真正是他们所说的人.

如何git push --signed帮助您(推动者)不必"信任"服务器？ 到目前为止,我所看到的一切似乎表明它有助于服务器信任您.更重要的是,为什么签名提交和签名标签不足以推送到不受信任的服务器？为什么我们甚至需要签名推送？