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Pieter 071ed083f7 feat: Implement per-client SSH key isolation 
Resolves #14

Each client now gets a dedicated SSH key pair, ensuring that compromise
of one client server does not grant access to other client servers.

## Changes

### Infrastructure (OpenTofu)
- Replace shared `hcloud_ssh_key.default` with per-client `hcloud_ssh_key.client`
- Each client key read from `keys/ssh/<client_name>.pub`
- Server recreated with new key (dev server only, acceptable downtime)

### Key Management
- Created `keys/ssh/` directory for SSH keys
- Added `.gitignore` to protect private keys from git
- Generated ED25519 key pair for dev client
- Private key gitignored, public key committed

### Scripts
- **`scripts/generate-client-keys.sh`** - Generate SSH key pairs for clients
- Updated `scripts/deploy-client.sh` to check for client SSH key

### Documentation
- **`docs/ssh-key-management.md`** - Complete SSH key management guide
- **`keys/ssh/README.md`** - Quick reference for SSH keys directory

### Configuration
- Removed `ssh_public_key` variable from `variables.tf`
- Updated `terraform.tfvars` to remove shared SSH key reference
- Updated `terraform.tfvars.example` with new key generation instructions

## Security Improvements

✅ Client isolation: Each client has dedicated SSH key
✅ Granular rotation: Rotate keys per-client without affecting others
✅ Defense in depth: Minimize blast radius of key compromise
✅ Proper key storage: Private keys gitignored, backups documented

## Testing

- ✅ Generated new SSH key for dev client
- ✅ Applied OpenTofu changes (server recreated)
- ✅ Tested SSH access: `ssh -i keys/ssh/dev root@78.47.191.38`
- ✅ Verified key isolation: Old shared key removed from Hetzner

## Migration Notes

For existing clients:
1. Generate key: `./scripts/generate-client-keys.sh <client>`
2. Apply OpenTofu: `cd tofu && tofu apply` (will recreate server)
3. Deploy: `./scripts/deploy-client.sh <client>`

For new clients:
1. Generate key first
2. Deploy as normal

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>
2026-01-17 19:50:30 +01:00
..
ssh feat: Implement per-client SSH key isolation 2026-01-17 19:50:30 +01:00
.gitignore Complete SOPS secrets management setup (#5) 2025-12-27 14:23:36 +01:00
README.md Complete SOPS secrets management setup (#5) 2025-12-27 14:23:36 +01:00

README.md

Age Encryption Keys

⚠️ CRITICAL: This directory contains encryption keys that are NOT committed to Git.

Key Files

  • age-key.txt - Age private key for SOPS encryption (GITIGNORED)

Backup Checklist

Before proceeding with any infrastructure work, ensure you have:

  • Copied age-key.txt to password manager
  • Created offline backup (printed or encrypted USB)
  • Verified backup can decrypt secrets successfully

Key Recovery

If you lose access to age-key.txt:

  1. Check password manager for backup
  2. Check offline backups (printed copy, USB drive)
  3. If no backup exists: Secrets are PERMANENTLY LOST
    • You will need to regenerate all secrets
    • Re-encrypt all .sops.yaml files
    • Update all services with new credentials

Generating a New Key

Only do this if you've lost the original key or need to rotate for security:

# Generate new Age key
age-keygen -o age-key.txt

# Extract public key
grep "public key:" age-key.txt

# Update .sops.yaml in repository root with new public key

# Re-encrypt all secrets
cd ..
for file in secrets/**/*.sops.yaml; do
  SOPS_AGE_KEY_FILE=keys/age-key.txt sops updatekeys -y "$file"
done

Security Notes

  • This directory is in .gitignore
  • Keys should never be shared via email, Slack, or unencrypted channels
  • Always use secure methods for key distribution (password manager, encrypted channels)