Как узнать электронную цифровую подпись (GPG) в git?

Так где найти эту электронную подпись ?

Что именно вы хотите найти?
Объект тега? Репозиторий с подписанным тегом? -- вот вам пример: https://git.kernel.org/cgit/linux/kernel/git/torva...
Ключ для подписи? -- вы должны его сгенерировать сами с помощью gpg --gen-key

jcmvbkbc: выскакивает ошибка, что делать ?

$ gpg --gen-key
gpg: error loading `iconv.dll': ═х эрщфхэ єърчрээ√щ ьюфєы№.

gpg: please see www.gnupg.org/download/iconv.html for more information
gpg (GnuPG) 1.4.13; Copyright (C) 2012 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

gpg: keyblock resource `c:/Users/Home/.gnupg\secring.gpg': file open error
gpg: keyblock resource `c:/Users/Home/.gnupg\pubring.gpg': file open error
Please select what kind of key you want:
(1) RSA and RSA (default)
(2) DSA and Elgamal
(3) DSA (sign only)
(4) RSA (sign only)
Your selection? yes
Invalid selection.
Your selection? master
Invalid selection.
Your selection? origin
Invalid selection.
Your selection? https://github.com/ruplex/public
Invalid selection.
Your selection? 1
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048)
Requested keysize is 2048 bits
Please specify how long the key should be valid.
0 = key does not expire
= key expires in n days
w = key expires in n weeks
m = key expires in n months
y = key expires in n years
Key is valid for? (0) y
invalid value
Key is valid for? (0) v
invalid value
Key is valid for? (0) <10>
invalid value
Key is valid for? (0) 10
Key expires at 02/09/15 20:04:16
Is this correct? (y/N) y

You need a user ID to identify your key; the software constructs the user ID
from the Real Name, Comment and Email Address in this form:
"Heinrich Heine (Der Dichter) "

Real name: Blood
Email address: vergil.300yandex.com
Comment: qq
You selected this USER-ID:
"Blood (qq) "

Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o
You need a Passphrase to protect your secret key.

We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
..........+++++
......+++++
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
......+++++
....+++++
gpg: no writable public keyring found: eof
Key generation failed: eof
gpg: can't create `c:/Users/Home/.gnupg\random_seed': No such file or directory

Home@HOME-PC /C/git/public (master)
$ gpg --gen-key
gpg: error loading `iconv.dll': ═х эрщфхэ єърчрээ√щ ьюфєы№.

gpg: please see www.gnupg.org/download/iconv.html for more information
gpg (GnuPG) 1.4.13; Copyright (C) 2012 Free Software Foundation, Inc.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

gpg: keyblock resource `c:/Users/Home/.gnupg\secring.gpg': file open error
gpg: keyblock resource `c:/Users/Home/.gnupg\pubring.gpg': file open error
Please select what kind of key you want:
(1) RSA and RSA (default)
(2) DSA and Elgamal
(3) DSA (sign only)
(4) RSA (sign only)
Your selection? 1
RSA keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048)
Requested keysize is 2048 bits
Please specify how long the key should be valid.
0 = key does not expire
= key expires in n days
w = key expires in n weeks
m = key expires in n months
y = key expires in n years
Key is valid for? (0) 10
Key expires at 02/09/15 20:12:07
Is this correct? (y/N) y

You need a user ID to identify your key; the software constructs the user ID
from the Real Name, Comment and Email Address in this form:
"Heinrich Heine (Der Dichter) "

Real name: Blood300
Email address: vergil.300yandex.com
Comment: qq
You selected this USER-ID:
"Blood300 (qq) "

Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? o
You need a Passphrase to protect your secret key.

We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
.+++++
...+++++
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
....+++++
.....+++++
gpg: no writable public keyring found: eof
Key generation failed: eof
gpg: can't create `c:/Users/Home/.gnupg\random_seed': No such file or directory

> gpg: can't create `c:/Users/Home/.gnupg\random_seed': No such file or directory
Похоже у вас какие-то проблемы с переменными окружения: в пути к файлу, который должен лежать в вашем домашнем каталоге отсутствует имя пользователя. Вероятно вам нужно экспортировать $HOME или $USER.