Procedures for backing up and restoring CA keys and certificates.

#!/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"

#!/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 <cluster-id>

#!/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"

#!/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 <backup-file.tar.gz>"
    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 ==="

#!/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
<Share-1-from-Custodian-A>
<Share-2-from-Custodian-B>
<Share-3-from-Custodian-C>
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

#!/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 ==="

• Key Ceremony - Secure key generation
• Emergency Revocation - On compromise
• Operations - Daily maintenance

« <- Disaster Recovery | -> Key Ceremony »

Wolfgang van der Stille @ EMSR DATA d.o.o. - Post-Quantum Cryptography Professional