自定义路径保存SSH密钥无法连接GitHub的问题求助

问题 #

当在非默认路径/名称生成SSH密钥时，无法通过SSH连接GitHub。多次尝试使用自定义名称的密钥均失败，但默认路径/名称生成的密钥可以正常工作，具体操作如下：

正常工作的操作 #

PS C:\Users\sjoao\.ssh> ssh-keygen -t ed25519 -C "sjoaovictor622@gmail.com"
Generating public/private ed25519 key pair.
Enter file in which to save the key (C:\Users\sjoao/.ssh/id_ed25519):
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in C:\Users\sjoao/.ssh/id_ed25519
Your public key has been saved in C:\Users\sjoao/.ssh/id_ed25519.pub
The key fingerprint is:
SHA256:sBpycUHR17hJwxtmDZFJgZSiNP9XBdlBP41AKQIEc5w sjoaovictor622@gmail.com
The key's randomart image is:
+--[ED25519 256]--+
|    o=B*.==@+*o. |
|    ooE.= & =.oo.|
|   ..+o. * B ...o|
|    .o.o  + .   .|
|  . o ..S  .     |
|   o o  . .      |
|    .    .       |
|                 |
|                 |
+----[SHA256]-----+
PS C:\Users\sjoao\.ssh> Start-Service ssh-agent
PS C:\Users\sjoao\.ssh> ssh-add .\id_ed25519
Identity added: .\id_ed25519 (sjoaovictor622@gmail.com)
PS C:\Users\sjoao\.ssh> Get-Content $env:USERPROFILE\.ssh\id_ed25519.pub | Set-Clipboard
PS C:\Users\sjoao\.ssh> git clone git@github.com:jottaVictor/tictactoegame.git
Cloning into 'tictactoegame'...
The authenticity of host 'github.com (20.201.28.151)' can't be established.
ED25519 key fingerprint is SHA256:+DiY3wvvV6TuJJhbpZisF/zLDA0zPMSvHdkr4UvCOqU.
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added 'github.com' (ED25519) to the list of known hosts.
remote: Enumerating objects: 135, done.
remote: Counting objects: 100% (135/135), done.
remote: Compressing objects: 100% (93/93), done.
remote: Total 135 (delta 47), reused 121 (delta 33), pack-reused 0 (from 0)
Receiving objects: 100% (135/135), 45.16 KiB | 388.00 KiB/s, done.
Resolving deltas: 100% (47/47), done.

无法工作的操作 #

PS C:\Users\sjoao\.ssh> ssh-keygen -t ed25519 -C "sjoaovictor622@gmail.com"
Generating public/private ed25519 key pair.
Enter file in which to save the key (C:\Users\sjoao/.ssh/id_ed25519): .\test
Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in .\test
Your public key has been saved in .\test.pub
The key fingerprint is:
SHA256:pOwOkkTVPPMaNn01y6VVmp1+B2P0MQgsfpDeq0KV7pM sjoaovictor622@gmail.com
The key's randomart image is:
+--[ED25519 256]--+
|    .o    o.. o+.|
|   .  =  + .ooo=+|
|  .    =+ =o **.o|
| .   .+oo=.o+..o |
|  .  .o+S.. .  .o|
| . . ... . .    o|
|  o . o . o      |
|   . o . E       |
|      . . .      |
+----[SHA256]-----+
PS C:\Users\sjoao\.ssh> Start-Service ssh-agent
PS C:\Users\sjoao\.ssh> ssh-add .\test
Identity added: .\test (sjoaovictor622@gmail.com)
PS C:\Users\sjoao\.ssh> Get-Content $env:USERPROFILE\.ssh\test.pub | Set-Clipboard
PS C:\Users\sjoao\.ssh> git clone git@github.com:jottaVictor/tictactoegame.git
Cloning into 'tictactoegame'...
The authenticity of host 'github.com (20.201.28.151)' can't be established.
ED25519 key fingerprint is SHA256:+DiY3wvvV6TuJJhbpZisF/zLDA0zPMSvHdkr4UvCOqU.
This key is not known by any other names.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added 'github.com' (ED25519) to the list of known hosts.
git@github.com: Permission denied (publickey).
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists.

操作的唯一区别是密钥保存名称，且两个公钥均已添加到GitHub的SSH密钥列表中，请问问题出在哪里？

问题原因与解决方法 #

• 核心原因：SSH客户端默认只会在~/.ssh/目录下查找id_rsa、id_ed25519这类默认命名的密钥文件，自定义名称的密钥不会被自动识别——哪怕你用ssh-add把它加入了agent，SSH连接GitHub时也不会主动匹配这个密钥。

• 解决方法：

  1. 在~/.ssh/目录下创建一个无扩展名的config文件，添加以下内容：

     Host github.com
         IdentityFile ~/.ssh/test  # 替换为你的自定义密钥路径
         IdentitiesOnly yes
     

  2. 保存文件后，重新执行git clone操作即可正常连接。

• 补充说明：

  • IdentitiesOnly yes用于强制SSH仅使用指定的密钥，避免agent尝试其他无关密钥导致验证冲突。
  • 若后续需要用不同自定义密钥连接不同主机，可在config文件中添加多个Host块分别配置。

内容的提问来源于stack exchange，提问作者Victor Santos