====== CA Backup/Restore ====== **Critical:** CA keys are the most valuable asset of the PKI! \\ **RTO:** 4 hours | **RPO:** 24 hours Procedures for backing up and restoring CA keys and certificates. ---- ===== Backup Components ===== | Component | Criticality | Backup Frequency | |-----------|-------------|------------------| | Root CA Private Key | **Critical** | Once + Offline | | Intermediate Private Keys | **High** | After each change | | CA Certificates | Medium | Daily | | CA Database (index.txt) | Medium | Daily | | Configuration (openssl.cnf) | Low | On change | | CRL Signing Key | High | With CA Key | ---- ===== Backup Strategy ===== flowchart TB subgraph LIVE["PRODUCTION"] L1[CA Server] L2[HSM] end subgraph BACKUP["BACKUP"] B1[Encrypted Backup] B2[HSM Backup Slot] B3[Shamir Shares] end subgraph OFFLINE["OFFLINE"] O1[Safe] O2[Custodians] O3[Off-Site] end L1 --> B1 --> O1 L2 --> B2 --> O3 L1 --> B3 --> O2 style L2 fill:#e8f5e9 style O1 fill:#e3f2fd ---- ===== Backup Procedures ===== ==== Software Keys (without HSM) ====


#!/bin/bash
# ca-backup.sh - Create CA backup

BACKUP_DIR="/backup/pki/$(date +%Y%m%d)"
ENCRYPTION_KEY="/etc/pki/backup-key.pem"  # RSA public key for encryption

mkdir -p "$BACKUP_DIR"

# 1. Private keys (encrypted)
echo "Backing up private keys..."
for key in /etc/pki/CA/*.key; do
    keyname=$(basename "$key" .key)

    # Encrypt with AES-256
    openssl enc -aes-256-cbc -salt -pbkdf2 \
        -in "$key" \
        -out "$BACKUP_DIR/${keyname}.key.enc" \
        -pass file:/etc/pki/backup-passphrase.txt

    # Or with RSA public key (asymmetric)
    openssl pkeyutl -encrypt \
        -pubin -inkey "$ENCRYPTION_KEY" \
        -in "$key" \
        -out "$BACKUP_DIR/${keyname}.key.rsa-enc"
done

# 2. Certificates
echo "Backing up certificates..."
cp /etc/pki/CA/*.pem "$BACKUP_DIR/"

# 3. CA database
echo "Backing up CA database..."
cp /etc/pki/CA/index.txt "$BACKUP_DIR/"
cp /etc/pki/CA/serial "$BACKUP_DIR/"
cp /etc/pki/CA/crlnumber "$BACKUP_DIR/"

# 4. Configuration
cp /etc/pki/CA/openssl.cnf "$BACKUP_DIR/"

# 5. Issued certificates
tar czf "$BACKUP_DIR/issued-certs.tar.gz" /etc/pki/CA/newcerts/

# 6. Checksums
cd "$BACKUP_DIR"
sha256sum * > SHA256SUMS

# 7. Full archive (optional)
cd /backup/pki
tar czf "ca-backup-$(date +%Y%m%d).tar.gz" "$(date +%Y%m%d)/"

echo "Backup completed: $BACKUP_DIR"

==== HSM-based Keys ====


#!/bin/bash
# hsm-backup.sh - HSM key backup

# Luna HSM
/usr/safenet/lunaclient/bin/lunacm << EOF
partition backup
    partition name = ca-partition
    backup file = /backup/hsm/ca-partition-$(date +%Y%m%d).bak
EOF

# Thales HSM
nShield-cknfastrc backup --slotlist=0 --output=/backup/hsm/nshield-$(date +%Y%m%d).bak

# AWS CloudHSM
aws cloudhsmv2 create-cluster-backup --cluster-id

==== Shamir Secret Sharing ====


#!/bin/bash
# shamir-split.sh - Distribute key to custodians

KEY_FILE="/etc/pki/CA/root-ca.key"
SHARES=5
THRESHOLD=3

# With ssss-split (Shamir's Secret Sharing Scheme)
cat "$KEY_FILE" | ssss-split -t $THRESHOLD -n $SHARES -w root-ca

# Result: 5 files (root-ca-1 to root-ca-5)
# At least 3 are needed for recovery

# Distribute to custodians
echo "Distribute shares to custodians:"
echo "  Share 1 -> Custodian A"
echo "  Share 2 -> Custodian B"
echo "  Share 3 -> Custodian C"
echo "  Share 4 -> Off-site safe"
echo "  Share 5 -> HSM escrow"

---- ===== Restore Procedures ===== ==== Software Keys ====


#!/bin/bash
# ca-restore.sh - Restore CA from backup

BACKUP_FILE="$1"
RESTORE_DIR="/etc/pki/CA"

if [ -z "$BACKUP_FILE" ]; then
    echo "Usage: $0 "
    exit 1
fi

echo "=== CA RESTORE ==="
echo "Backup: $BACKUP_FILE"
read -p "Continue? (yes/no): " confirm
[ "$confirm" != "yes" ] && exit 1

# 1. Back up current state
echo "Backing up current state..."
mv "$RESTORE_DIR" "${RESTORE_DIR}.pre-restore-$(date +%Y%m%d%H%M%S)"

# 2. Extract backup
echo "Extracting backup..."
mkdir -p "$RESTORE_DIR"
tar xzf "$BACKUP_FILE" -C "$RESTORE_DIR" --strip-components=1

# 3. Decrypt private keys
echo "Decrypting private keys..."
for enc_key in "$RESTORE_DIR"/*.key.enc; do
    keyname=$(basename "$enc_key" .key.enc)
    openssl enc -aes-256-cbc -d -pbkdf2 \
        -in "$enc_key" \
        -out "$RESTORE_DIR/${keyname}.key" \
        -pass file:/etc/pki/backup-passphrase.txt
    rm "$enc_key"
done

# 4. Set permissions
chmod 600 "$RESTORE_DIR"/*.key
chmod 644 "$RESTORE_DIR"/*.pem
chown -R root:root "$RESTORE_DIR"

# 5. Verify
echo "Verifying restoration..."
for key in "$RESTORE_DIR"/*.key; do
    cert="${key%.key}.pem"
    if [ -f "$cert" ]; then
        key_mod=$(openssl rsa -in "$key" -noout -modulus 2>/dev/null | md5sum)
        cert_mod=$(openssl x509 -in "$cert" -noout -modulus 2>/dev/null | md5sum)
        if [ "$key_mod" = "$cert_mod" ]; then
            echo "OK $(basename "$key"): Key/Cert match"
        else
            echo "ERROR $(basename "$key"): MISMATCH!"
        fi
    fi
done

# 6. Start CA services
echo "Starting CA services..."
systemctl start pki-ca
systemctl start ocsp-responder

echo "=== RESTORE COMPLETED ==="

==== Combine Shamir Shares ====


#!/bin/bash
# shamir-combine.sh - Restore key from shares

echo "Shamir Share Recovery"
echo "At least 3 of 5 shares required"

# Collect shares (from custodians)
ssss-combine -t 3 > /tmp/restored-key.tmp << EOF



EOF

# Verify
openssl rsa -in /tmp/restored-key.tmp -check -noout
if [ $? -eq 0 ]; then
    echo "Key successfully restored"
    mv /tmp/restored-key.tmp /etc/pki/CA/root-ca.key
    chmod 600 /etc/pki/CA/root-ca.key
else
    echo "ERROR: Key invalid!"
    rm /tmp/restored-key.tmp
fi

---- ===== Backup Verification =====


#!/bin/bash
# verify-backup.sh - Verify backup integrity

BACKUP_DIR="$1"

echo "=== Backup Verification ==="

# Verify checksums
cd "$BACKUP_DIR"
sha256sum -c SHA256SUMS
if [ $? -ne 0 ]; then
    echo "ERROR: Checksum mismatch!"
    exit 1
fi

# Verify key/cert pairs
for enc_key in *.key.enc; do
    keyname=$(basename "$enc_key" .key.enc)
    cert="${keyname}.pem"

    if [ ! -f "$cert" ]; then
        echo "WARNING: No certificate for $keyname"
        continue
    fi

    # Decrypt and verify (temporarily)
    openssl enc -aes-256-cbc -d -pbkdf2 \
        -in "$enc_key" \
        -out /tmp/verify.key \
        -pass file:/etc/pki/backup-passphrase.txt

    key_mod=$(openssl rsa -in /tmp/verify.key -noout -modulus 2>/dev/null | md5sum)
    cert_mod=$(openssl x509 -in "$cert" -noout -modulus 2>/dev/null | md5sum)

    if [ "$key_mod" = "$cert_mod" ]; then
        echo "OK $keyname: OK"
    else
        echo "ERROR $keyname: MISMATCH!"
    fi

    rm /tmp/verify.key
done

echo "=== Verification completed ==="

---- ===== Backup Schedule ===== | Component | Frequency | Retention | Medium | |-----------|-----------|-----------|--------| | CA Database | Daily | 30 days | Disk -> Tape | | Intermediate Keys | Weekly | 1 year | Encrypted Disk | | Root CA Key | Once | Permanent | Offline Safe | | Configuration | On change | 5 versions | Git | ---- ===== Checklist ===== | # | Checkpoint | Done | |---|------------|------| | 1 | Backup script configured | | | 2 | Encryption key securely stored | | | 3 | Shamir shares distributed | | | 4 | Backup cron active | | | 5 | Off-site backup available | | | 6 | Restore test successful | | | 7 | Last verification < 30 days | | ---- ===== Related Documentation ===== * [[.:key-ceremony|Key Ceremony]] - Secure key generation * [[.:notfall-revocation|Emergency Revocation]] - On compromise * [[en:int:pqcrypt:administrator:betrieb|Operations]] - Daily maintenance ---- << [[.:start|<- Disaster Recovery]] | [[.:key-ceremony|-> Key Ceremony]] >> ---- //Wolfgang van der Stille @ EMSR DATA d.o.o. - Post-Quantum Cryptography Professional// {{tag>backup restore disaster-recovery ca operator}}