132 lines
7.6 KiB
Markdown
132 lines
7.6 KiB
Markdown
### System Overview
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The goal is to create a platform where citizens can anonymously submit opinions on legislative matters, with those opinions influencing lawmakers, while guaranteeing transparency and security. Zero-Knowledge Proofs, a cryptographic tool, enable participants to prove eligibility and uniqueness without revealing their identities. The system integrates digital credentials, blind signatures, and ZKPs, optionally leveraging a blockchain for decentralization and auditability.
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---
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### Key Features
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1. **Anonymity**: Participants’ identities remain hidden, even from the system and authorities.
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2. **Eligibility**: Only authorized individuals (e.g., citizens) can participate.
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3. **Uniqueness**: Each participant submits only one opinion per legislative matter.
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4. **Transparency**: All submissions and proofs are publicly verifiable.
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5. **Security**: Cryptographic methods prevent fraud, manipulation, or duplicate submissions.
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---
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### System Components
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- **Participants**: Individuals with a digital credential (e.g., issued by a trusted authority based on citizenship).
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- **Trusted Authority**: Issues credentials and blind signatures to ensure eligibility.
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- **Public Ledger (Optional Blockchain)**: Stores commitments, submissions, and proofs for transparency and verification.
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- **Legislative Matters**: Each matter (e.g., a proposed law) has a unique identifier, called a “matter ID.”
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---
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### How the System Works
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The system operates in two main phases: **Setup** and **Opinion Submission**.
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#### 1. Setup Phase
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For each legislative matter identified by a unique matter ID:
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- **Credential Issuance**: Each participant has a digital credential from a trusted authority, proving eligibility (e.g., citizenship). This credential is private and tied to their identity initially but anonymized in later steps.
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- **Token and Commitment Generation**:
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- For each matter, the participant generates:
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- A **unique token** (a random value specific to that matter).
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- A **secret key** (a private value known only to them).
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- They create a **commitment**—a cryptographic hash of the token and secret key combined with the matter ID. This commitment hides the token and key but can later be proven to match them.
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- **Blind Signature Request**:
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- The participant sends the commitment and matter ID to the authority, with the token portion blinded (using a blind signature scheme like Chaum’s blind signatures).
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- The authority verifies that this credential hasn’t requested a signature for this matter ID before, then issues a **partially blind signature**. The signature includes the matter ID (visible to the authority) and the blinded commitment.
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- The participant unblinds the signature, obtaining a valid signature on their commitment tied to the matter ID.
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- **Publishing Commitments**:
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- The participant publishes the commitment and its blind signature to a public ledger (e.g., a blockchain or database).
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- The authority ensures each credential gets only one signature per matter, limiting each participant to one commitment per matter.
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At the end of the setup phase, there’s a public list of commitments for each matter, each with a valid blind signature, ensuring only eligible participants contribute exactly one commitment.
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#### 2. Opinion Submission Phase
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When a participant wants to submit an opinion on a legislative matter:
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- **Submission Content**:
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- The participant reveals their **token** for that matter.
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- They provide their **opinion** (e.g., “yes,” “no,” or a short statement).
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- They generate a **Zero-Knowledge Proof (ZKP)** that proves:
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1. There exists a commitment in the public list for this matter ID where the revealed token matches the committed token.
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2. They know the secret key associated with that commitment.
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- **Verification**:
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- The system (or a smart contract on a blockchain) verifies:
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- The commitment referenced by the ZKP has a valid blind signature from the authority.
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- The ZKP is correct, confirming the token’s legitimacy and the participant’s knowledge of the secret key.
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- The token hasn’t been used before for this matter (checked against a list of used tokens).
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- **Recording**:
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- If valid, the system accepts the opinion, records it publicly with the token and ZKP, and marks the token as used.
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---
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### Ensuring Core Requirements
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- **Anonymity**:
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- Blind signatures ensure the authority doesn’t link commitments to participants.
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- The ZKP hides which commitment corresponds to the submission, mixing it among all participants’ commitments.
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- Tokens are unique per matter and unlinkable across matters, preventing profiling.
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- **Eligibility**:
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- Only participants with a valid credential can obtain blind signatures and publish commitments.
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- **Uniqueness**:
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- The authority issues one blind signature per credential per matter, limiting each participant to one commitment.
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- The ZKP and token check ensure each commitment submits only one opinion per matter.
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- **Transparency**:
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- All commitments, signatures, opinions, tokens, and ZKPs are public. Anyone can verify that submissions correspond to valid commitments and that no token is reused.
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- **Security**:
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- ZKPs require knowledge of the secret key, preventing token theft.
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- Blind signatures and commitments prevent the authority or outsiders from manipulating the process.
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- A blockchain (if used) ensures tamper-proof records.
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---
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### Optional Blockchain Integration
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For enhanced transparency and decentralization:
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- **Commitments**: Stored as transactions on the blockchain during setup.
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- **Submissions**: Each opinion submission is a transaction, verified by a smart contract that checks the ZKP and token uniqueness.
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- **Auditability**: The blockchain provides a tamper-proof log, allowing anyone to audit the process without trusting a central entity.
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This reduces reliance on a single authority, though the authority still issues initial credentials and signatures. A fully decentralized identity system could further minimize this dependency.
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---
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### Scalability and Efficiency
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- **Large Populations**: For millions of participants, the system manages large lists of commitments and used tokens. Modern databases or blockchains (e.g., Ethereum with rollups) can handle this scale.
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- **Efficient ZKPs**: Using zk-SNARKs or zk-STARKs, proofs are small (e.g., a few hundred bytes) and verification is fast (e.g., milliseconds), making the system practical.
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- **Setup Overhead**: Participants generate commitments per matter, which could be streamlined with reusable credentials, but the current design prioritizes security and simplicity.
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---
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### Example Workflow
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1. **Setup for Matter “Law123”**:
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- Alice, with credential C1, generates token T1 and secret key S1, commits to them as Com1 = Hash(T1, S1, “Law123”).
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- She gets a blind signature Sig1 from the authority on Com1 for “Law123” and publishes (Com1, Sig1).
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2. **Submission**:
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- Alice submits her opinion “Yes” on “Law123” with:
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- Token T1.
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- ZKP proving T1 matches a commitment (e.g., Com1) and she knows S1.
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- The system verifies Sig1, the ZKP, and that T1 is unused, then records “Yes” with T1.
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3. **Public Check**:
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- Anyone sees (Com1, Sig1) in the list, verifies Sig1, and confirms T1’s submission is valid and unique.
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---
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### Conclusion
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This system leverages ZKPs, blind signatures, and a public ledger to crowdsource public opinion securely and transparently. It ensures anonymity and fairness while allowing lawmakers to trust the authenticity of the input, making it a robust tool for democratic participation in legislation. |