Secure Search Index for PII Detection Using Perfect Hashing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for detecting personally identifiable information (PII) on untrusted devices pose data leakage and compliance risks due to the need for decryption keys and limitations in cryptographic hashing techniques, especially when the identifier space is small, making it vulnerable to reconstruction attacks.
Innovation Solution
A secure search index is created using perfect hash functions and shift-split hashing to map sensitive identifiers to a smaller key space, generating hashed keys that are unique to each record, reducing the risk of collision and intersection attacks, and distributing these keys to untrusted entities for detection without exposing the original PII.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If encryption is used to protect PII database on untrusted devices, then data security is improved, but the entity performing detection becomes a potential source of data leakage requiring access to decryption keys
Solution Approach 1:
The patent extracts the sensitive PII data from the detection process by using cryptographic hashing to transform PII into fixed-length hash values. The original PII never appears in plaintext on the untrusted device, eliminating the data leakage risk while maintaining detection capability through hash matching.
Solution Approach 2:
The patent introduces cryptographic hash functions as an intermediary between the original PII data and the detection process. This intermediary transforms sensitive data into non-reversible hash representations, allowing detection operations on untrusted devices without exposing the underlying PII.
2Reliability
If cryptographic hashing is used to protect PII, then data security is improved, but hashing is limited by entropy of underlying identifiers making it vulnerable to reconstruction attacks when identifier space is small
Solution Approach 1:
The patent combines multiple cryptographic techniques into a composite protection scheme: cryptographic hashing of PII to create base hash values, then applying a second layer of hashing or transformation to these hash values. This composite approach creates a more robust security layer that resists reconstruction attacks even when the original identifier space is small.
Solution Approach 2:
The patent performs preliminary cryptographic hashing of PII data before it reaches the untrusted device. By pre-transforming the data into hash form and storing only the hash representations on untrusted devices, the system eliminates the vulnerability to reconstruction attacks that would exist if original PII or weakly-hashed PII were stored.
3Productivity
If PII database is stored on untrusted endpoint devices, then detection capability is improved, but data loss and compliance risk increase
Solution Approach 1:
The patent creates cryptographic copies of PII data in the form of hash values that can be distributed to untrusted devices for detection purposes. These hash copies maintain the functional capability for detection while being inherently protected from misuse, as they cannot be reversed to obtain the original PII.
Solution Approach 2:
The patent uses cryptographic hashing as an intermediary mechanism that enables detection operations on untrusted devices without requiring those devices to handle or store actual PII data. The hash values serve as safe intermediaries that preserve detection functionality while eliminating compliance risks.
Data Source
AI summary
The disclosed computer-implemented method for preparing a secure search index for securely detecting personally identifiable information may include (i) receiving, at a computing device, a dataset including a record, where the record has a field including a value describing personally identifiable information and (ii) performing, at the computing device, a security action. The security action may include (i) generating, using a perfect hash function, a respective hashed key from the value and (ii) adding, to the secure search index (a) the respective hashed key or (b) a subsequent hashed key created from the respective hashed key. Various other methods, systems, and computer-readable media are also disclosed.