Published
Aug 20, 2024
Updated
Aug 20, 2024

How Double Model Balancing (DOMBA) Solves AI’s Access Control Problem

DOMBA: Double Model Balancing for Access-Controlled Language Models via Minimum-Bounded Aggregation
By
Tom Segal|Asaf Shabtai|Yuval Elovici

Summary

Imagine training a powerful AI on your company's data to create an email assistant, but that data also has restricted information. How do you prevent the AI from accidentally revealing financial reports to the marketing team, while still letting it craft marketing emails that draw upon company-wide data for peak effectiveness? This is the core challenge of access control for Large Language Models (LLMs). Researchers at Ben Gurion University have developed a clever solution called DOMBA – Double Model Balancing – that elegantly sidesteps this problem. DOMBA’s secret lies in training two separate AI models. Each model learns from different parts of your company’s data, according to the access restrictions in place. One model might learn from sales and finance, while the other focuses on marketing, HR, and product. The magic happens during text generation: DOMBA doesn’t just rely on one model. Instead, it uses a special averaging method that blends the outputs of *both* models to determine the probability of each word in the generated text. This "min-bounded" averaging prioritizes agreement between the models. If one model is highly confident about a word or phrase, while the other is uncertain, it indicates specialized information. This word is much less likely to be included in the final generated output. This ingenious approach keeps the LLM from revealing information only one model "knows," thus safeguarding restricted data. The team behind DOMBA introduced some clever evaluation metrics: 'exposure,' to measure how much sensitive information leaks out; ‘secret perplexity,’ assessing how well the AI handles sensitive phrases; and a ‘secret inference attack’ that mimics how a hacker might try to extract information. Results across movie reviews and recipes demonstrate that DOMBA provides a solid balance between utility and security. It doesn't perfectly shield *all* restricted information, but achieves a robust, practical level of protection while keeping the LLM useful. Future development of DOMBA holds exciting possibilities. The min-bounded averaging core is an elegant solution for managing sensitive information in LLMs, whether for access control or general data privacy. It also allows for more training epochs and a more extensive dataset without the same risk of overfitting as other solutions, while still producing an effective balance between utility and privacy.
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Question & Answers

How does DOMBA's min-bounded averaging mechanism work to protect sensitive information?
DOMBA's min-bounded averaging mechanism combines outputs from two separately trained AI models to control information access. The system works by comparing probability distributions from both models during text generation. When generating text, if one model shows high confidence about a word while the other shows uncertainty, this indicates potentially sensitive information and the word receives a lower probability of being included. For example, in a corporate setting, if the finance-trained model is confident about revenue figures while the marketing-trained model is uncertain, DOMBA's averaging mechanism would suppress this sensitive financial information in the generated output. This creates an effective barrier against unauthorized information disclosure while maintaining useful general knowledge.
What are the main benefits of using AI access control systems in business?
AI access control systems provide crucial benefits for modern businesses by protecting sensitive information while maintaining productivity. These systems allow organizations to safely leverage their data by ensuring different departments only access appropriate information - for instance, keeping financial data separate from marketing operations. Key advantages include reduced data breach risks, improved regulatory compliance, and maintained operational efficiency. Practical applications include secure document handling, email management, and customer service systems where AI can safely access relevant information without exposing protected data. This balanced approach helps businesses maximize AI benefits while minimizing security risks.
How can AI help organizations better manage sensitive data?
AI can revolutionize sensitive data management through intelligent filtering and access control mechanisms. Modern AI systems can automatically classify data sensitivity levels, monitor access patterns, and prevent unauthorized information sharing while maintaining operational efficiency. For example, AI can screen communications for sensitive content, manage document access permissions dynamically, and ensure compliance with data protection regulations. Organizations benefit from reduced manual oversight, fewer security incidents, and more streamlined workflows. This technology is particularly valuable in industries handling confidential information like healthcare, finance, and legal services.

PromptLayer Features

  1. Access Control Management
  2. DOMBA's dual-model approach aligns with PromptLayer's access control capabilities for managing sensitive data access across teams
Implementation Details
Configure separate prompt templates and access permissions for different user groups, mirror DOMBA's dual-model architecture through segregated prompt spaces
Key Benefits
• Granular control over sensitive data access • Reduced risk of unauthorized information exposure • Maintained model utility while preserving privacy
Potential Improvements
• Add dynamic access level adjustments • Implement automated access audit trails • Create role-based prompt template inheritance
Business Value
Efficiency Gains
Streamlined management of sensitive data access across teams
Cost Savings
Reduced risk of data breaches and associated costs
Quality Improvement
Better compliance with data privacy requirements while maintaining AI functionality
  1. Testing & Evaluation
  2. DOMBA's evaluation metrics (exposure, secret perplexity, secret inference attack) can be implemented through PromptLayer's testing framework
Implementation Details
Create automated test suites that measure information leakage and model performance using DOMBA's metrics
Key Benefits
• Comprehensive security testing automation • Consistent evaluation of privacy preservation • Early detection of potential data leaks
Potential Improvements
• Implement real-time security metric monitoring • Add customizable privacy threshold alerts • Develop automated regression testing for security metrics
Business Value
Efficiency Gains
Automated validation of privacy preservation
Cost Savings
Reduced manual security testing effort
Quality Improvement
More reliable and consistent privacy protection measures

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