Complete Guide: Multiple Git Accounts with SSH, GPG, and Verified Commits

# 🔐 PART 1 — Generate 2 SSH Keys (Access)

1. Generate GitHub SSH key

ssh-keygen -t ed25519 -C "user-github@mail.com" -f ~/.ssh/id_ed25519_github

2. Generate GitLab SSH key

ssh-keygen -t ed25519 -C "user-gitlab@mail.com" -f ~/.ssh/id_ed25519_gitlab

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3. Add SSH config

Edit:

nano ~/.ssh/config

Add:

Host github.com
  HostName github.com
  User user-github@mail.com
  IdentityFile ~/.ssh/id_ed25519_github
  IdentitiesOnly yes

Host gitlab.com
  HostName gitlab.com
  User user-gitlab@mail.com
  IdentityFile ~/.ssh/id_ed25519_gitlab
  IdentitiesOnly yes

4. Add public keys to platforms

Copy keys:

cat ~/.ssh/id_ed25519_github.pub
cat ~/.ssh/id_ed25519_gitlab.pub

Add to:

GitHub → Settings → SSH Keys
GitLab → Preferences → SSH Keys

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5. Test connection

ssh -T git@github.com
ssh -T git@gitlab.com

# ✍️ PART 2 — Generate 2 GPG Keys (Signing)

1. Generate GitHub GPG key

gpg --full-generate-key

Choose:

Type: RSA and RSA
Key size: 4096
Email: same as GitHub email

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2. Generate GitLab GPG key

Run again:

gpg --full-generate-key

Use GitLab email

3. List keys

gpg --list-secret-keys --keyid-format=long

Example output:

sec   rsa4096/ABC1234567890
uid   [ultimate] user-github@mail.com

sec   rsa4096/XYZ9876543210
uid   [ultimate] user-gitlab@mail.com

👉 Save both KEY IDs:

GitHub → ABC1234567890
GitLab → XYZ9876543210

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4. Export public keys

gpg --armor --export ABC1234567890
gpg --armor --export XYZ9876543210

5. Add to platforms

GitHub → Settings → GPG Keys
GitLab → Preferences → GPG Keys

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# ⚙️ PART 3 — Git Config Per Workspace (IMPORTANT)

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1. Create separate config files

GitHub config

nano ~/.gitconfig-github

[user]
  email = user-github@mail.com
  signingkey = ABC1234567890

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GitLab config

nano ~/.gitconfig-gitlab

[user]
  email = user-gitlab@mail.com
  signingkey = XYZ9876543210

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2. Setup auto switching

Edit main config:

nano ~/.gitconfig