Implement PQC Hybrid Signature Infrastructure for Receipts and Audit Logs

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Objective

Implement PQC (post-quantum cryptography) hybrid signature mechanisms for verifiable receipts and evidence chains, per patent claims #12 & #15. Ensure that new and existing audit logs and confirmation receipts are cryptographically signed with both a classical and PQC algorithm. Prepare all cryptosignature modules to be easily updated as NIST algorithms standardize.

Core Implementation

• Integrate liboqs-python or pqcrypto for Falcon or Dilithium signatures alongside classical (RSA/Ed25519)
• Implement dual-signing modules in security/pqc_signer.py and update all crypto-receipt paths
• Add test vectors and cryptographic audit logging
• Provide detailed documentation on hybridization mechanisms, reasoning, and upgradability

Acceptance Criteria

• PQC-enhanced receipt/log system passes security review
• All cryptographic operations logged and tested
• Documentation is auditor/investor ready

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Independent Issue