我正在尝试将本地签名添加到我的密钥环中的一些公钥中，但使用gpg --lsign-key失败并显示“无密钥”消息，尽管事实上gpg --sign有效。我使用 Yubikey 作为智能卡。

GPG 显示密钥不可用，但附加的智能卡上有签名密钥：

$ gpg --list-secret-keys
sec#  rsa4096/0xDEADBEEFDEADBEEF 2000-01-01 [SC]
      Key fingerprint = DEAD BEEF DEAD BEEF DEAD  BEEF DEAD BEEF DEAD BEEF
uid                   [ultimate] My Name <me@example.com>
ssb>  rsa4096/0x8BADF00D8BADF00D 2000-01-01 [E] [expires: 2020-12-31]
ssb>  rsa4096/0xBADDCAFEBADDCAFE 2000-01-01 [S] [expires: 2020-12-31]
ssb>  rsa4096/0xFACEFEEDFACEFEED 2000-01-01 [A] [expires: 2020-12-31]

我可以签署一条消息：

$ echo "test" | gpg --sign --armor
gpg: using "DEADBEEFDEADBEEFDEADBEEFDEADBEEFDEADBEEF" as default secret key for signing
-----BEGIN PGP MESSAGE-----

[snipped signature]
-----END PGP MESSAGE-----

但我不能--lsign-key：

$ gpg --lsign-key product-security@apple.com

pub  rsa4096/0x782F6D86DED32B71
     created: 2018-08-20  expires: 2019-08-20  usage: SC
     trust: marginal      validity: unknown
sub  rsa4096/0x1C3F44E9CB9F9E3A
     created: 2018-08-20  expires: 2019-08-20  usage: E
[ unknown] (1). Apple Product Security <product-security@apple.com>
[ unknown] (2)  Apple Product Security Notifications <product-security-noreply@lists.apple.com>

Really sign all user IDs? (y/N) y
gpg: using "DEADBEEFDEADBEEFDEADBEEFDEADBEEFDEADBEEF" as default secret key for signing

pub  rsa4096/0x782F6D86DED32B71
     created: 2018-08-20  expires: 2019-08-20  usage: SC
     trust: marginal      validity: unknown
 Primary key fingerprint: 0CD5 C954 D089 2440 1598  9759 782F 6D86 DED3 2B71

     Apple Product Security <product-security@apple.com>
     Apple Product Security Notifications <product-security-noreply@lists.apple.com>

This key is due to expire on 2019-08-20.
Are you sure that you want to sign this key with your
key "My Name <me@example.com>" (0xDEADBEEFDEADBEEF)

The signature will be marked as non-exportable.

Really sign? (y/N) y
gpg: signing failed: No secret key
gpg: signing failed: No secret key

Key not changed so no update needed.

如何向此密钥添加签名以对其进行验证？