Chapter 3: Technical Implementation

// Pseudocode for Data Discovery
class DataDiscoveryEngine {
    async discoverUserData(userId: string): Promise {
        const locations = [];

        // Scan primary databases
        for (const database of this.databases) {
            const tables = await this.scanDatabaseForUser(database, userId);
            locations.push(...tables);
        }

        // Search document stores
        for (const docStore of this.documentStores) {
            const documents = await this.searchDocuments(docStore, userId);
            locations.push(...documents);
        }

        // Check caching layers
        const cacheEntries = await this.scanCaches(userId);
        locations.push(...cacheEntries);

        // Query analytics platforms
        const analyticsData = await this.findInAnalytics(userId);
        locations.push(...analyticsData);

        // Search backup systems
        const backupLocations = await this.locateInBackups(userId);
        locations.push(...backupLocations);

        return this.deduplicateAndValidate(locations);
    }

    async scanDatabaseForUser(db: Database, userId: string): Promise {
        const locations = [];
        const tables = await db.getTables();

        for (const table of tables) {
            const columns = await table.getColumns();
            const userIdColumns = this.identifyUserIdColumns(columns);

            for (const column of userIdColumns) {
                const records = await table.query(
                    `SELECT * FROM ${table.name} WHERE ${column} = ?`,
                    [userId]
                );

                if (records.length > 0) {
                    locations.push({
                        system: db.name,
                        location: table.name,
                        column: column,
                        recordCount: records.length,
                        dataTypes: this.analyzeDataTypes(records)
                    });
                }
            }
        }

        return locations;
    }
}

// Implementation of DoD 5220.22-M Secure Deletion
class SecureDeletion {
    async secureDelete(dataLocation: DataLocation): Promise {
        // Pass 1: Random character overwrite
        await this.overwriteWithRandom(dataLocation);

        // Pass 2: Complement overwrite
        await this.overwriteWithComplement(dataLocation);

        // Pass 3: Random character and verify
        await this.overwriteWithRandom(dataLocation);
        const verified = await this.verifyOverwrite(dataLocation);

        if (!verified) {
            throw new Error('Secure deletion verification failed');
        }

        // Finally, delete the overwritten records
        await this.executeDelete(dataLocation);

        return {
            location: dataLocation,
            method: 'DoD-5220.22-M',
            passes: 3,
            verified: true,
            timestamp: new Date().toISOString(),
            hash: this.generateVerificationHash(dataLocation)
        };
    }

    private async overwriteWithRandom(location: DataLocation): Promise {
        const randomData = this.generateSecureRandom(location.size);
        await this.writeToLocation(location, randomData);
    }

    private async overwriteWithComplement(location: DataLocation): Promise {
        const currentData = await this.readFromLocation(location);
        const complement = this.computeComplement(currentData);
        await this.writeToLocation(location, complement);
    }

    private async verifyOverwrite(location: DataLocation): Promise {
        const data = await this.readFromLocation(location);
        return this.isEffectivelyRandomized(data);
    }
}

// Distributed Deletion with Verification
class DistributedDeletionOrchestrator {
    async deleteAcrossReplicas(
        userId: string,
        replicas: DatabaseReplica[]
    ): Promise {
        const results = [];

        // Step 1: Delete from all replicas
        const deletionPromises = replicas.map(replica =>
            this.deleteFromReplica(replica, userId)
        );

        const deletionResults = await Promise.allSettled(deletionPromises);

        // Step 2: Verify deletion
        await this.waitForReplicationLag();

        for (const [index, replica] of replicas.entries()) {
            const verificationResult = await this.verifyDeletion(replica, userId);
            results.push({
                replica: replica.id,
                deletion: deletionResults[index],
                verification: verificationResult
            });
        }

        // Step 3: Handle failures
        const failures = results.filter(r => !r.verification.success);
        if (failures.length > 0) {
            await this.handleDeletionFailures(failures);
        }

        return {
            totalReplicas: replicas.length,
            successful: results.filter(r => r.verification.success).length,
            failed: failures.length,
            details: results
        };
    }

    private async waitForReplicationLag(): Promise {
        // Wait for expected replication time plus buffer
        const replicationTime = this.calculateExpectedReplicationTime();
        await new Promise(resolve => setTimeout(resolve, replicationTime));
    }
}

// Microservices Deletion Coordinator
class MicroservicesDeletionCoordinator {
    async orchestrateDeletion(userId: string): Promise {
        // Step 1: Discover all services with user data
        const services = await this.discoverServicesWithUserData(userId);

        // Step 2: Create deletion plan
        const plan = this.createDeletionPlan(services);

        // Step 3: Execute deletions in dependency order
        for (const phase of plan.phases) {
            await this.executePhase(phase, userId);
        }

        // Step 4: Verify across all services
        const verification = await this.verifyCompleteDeletion(services, userId);

        return {
            services: services.map(s => s.name),
            totalRecords: verification.deletedRecords,
            success: verification.allDeleted,
            certificate: this.generateCertificate(verification)
        };
    }

    private createDeletionPlan(services: Service[]): DeletionPlan {
        // Topologically sort services based on dependencies
        const graph = this.buildDependencyGraph(services);
        const sorted = this.topologicalSort(graph);

        // Group into phases (services with no dependencies between them)
        const phases = this.groupIntoParallelPhases(sorted);

        return { phases };
    }

    private async executePhase(
        phase: Service[],
        userId: string
    ): Promise {
        // Execute deletions in parallel within phase
        await Promise.all(
            phase.map(service => this.deleteFromService(service, userId))
        );
    }
}

// Backup Management for RTBF Compliance
class BackupDeletionManager {
    async handleBackupDeletion(userId: string): Promise {
        const strategy = this.selectStrategy();

        switch (strategy) {
            case 'regenerate':
                return await this.regenerateBackups(userId);

            case 'markers':
                return await this.addDeletionMarker(userId);

            case 'expiring':
                return await this.documentBackupExpiry(userId);
        }
    }

    private async regenerateBackups(userId: string): Promise {
        const backups = await this.listActiveBackups();

        for (const backup of backups) {
            // Restore backup to temporary location
            const tempDb = await this.restoreToTemporary(backup);

            // Delete user data from restored backup
            await this.deleteFromDatabase(tempDb, userId);

            // Create new backup without deleted user
            await this.createCleanBackup(tempDb, backup.label);

            // Clean up temporary database
            await this.cleanupTemporary(tempDb);
        }

        return {
            strategy: 'regenerate',
            backupsProcessed: backups.length,
            status: 'complete'
        };
    }

    private async addDeletionMarker(userId: string): Promise {
        // Add to deletion marker database
        await this.deletionMarkerDb.insert({
            userId: userId,
            deletedAt: new Date(),
            applyToBackups: true
        });

        // Update restore procedures to filter this user
        await this.updateRestoreProcedures();

        return {
            strategy: 'markers',
            markerAdded: true,
            status: 'complete'
        };
    }
}

// Cache Invalidation for RTBF
class CacheInvalidationService {
    async invalidateUserData(userId: string): Promise {
        // Invalidate application caches
        await this.invalidateApplicationCache(userId);

        // Purge from CDN
        await this.purgeCDNCache(userId);

        // Clear search indices
        await this.updateSearchIndices(userId);
    }

    private async invalidateApplicationCache(userId: string): Promise {
        // Identify all cache keys related to this user
        const cacheKeys = await this.findUserCacheKeys(userId);

        // Delete from all cache layers
        await Promise.all([
            this.redis.del(cacheKeys),
            this.memcached.delete(cacheKeys),
            this.localCache.invalidate(cacheKeys)
        ]);
    }

    private async purgeCDNCache(userId: string): Promise {
        // Identify URLs containing user data
        const urls = await this.findUserUrls(userId);

        // Purge from CDN providers
        await Promise.all([
            this.cloudfront.createInvalidation({ paths: urls }),
            this.fastly.purgeUrls(urls),
            this.akamai.invalidate(urls)
        ]);
    }
}