Real-time consent ledger, modular metadata audit & cross-platform consent token system

Abstract

Computer-implemented consent management comprising a Real-Time Consent Ledger (RTCL; 101, fig.1) that receives user consent updates 601 and calculates a delta of the changes 602 to the state of the co

Description

[0001] The invention relates to computer-implemented consent management systems enabling efficient real-time consent synchronisation, structured auditability, and decentralised enforcement of user-defined consent preferences across distributed digital environments through cryptographic protocols and modular metadata management methods. Background of the Invention

[0002] Effective management of user consent is required by privacy regulations such as UK GDPR and EU GDPR. Digital platforms must maintain accurate consent preferences, promptly update these preferences, and enforce them consistently across multiple services and jurisdictions. However, current consent management solutions suffer several technical limitations: (i) Many systems rely on full-state synchronisation, repeatedly transmitting entire consent datasets, causing significant bandwidth overhead and slow response times under real-time conditions. (ii) Traditional linear audit trails lack modular indexing and structured categorisation, making regulatory queries inefficient and compliance verification cumbersome. (iii) Consent enforcement often depends on centralised infrastructures for interpretation and validation, limiting user autonomy and cross-platform interoperability. (iv) Existing cryptographic consent tokens typically lack portability and independent validation capabilities, constraining their effectiveness in decentralised contexts.

[0003] Together, these limitations lead to performance bottlenecks, increased latency, inefficient audit processes, and compromised reliability of consent enforcement. Technical Problem Addressed

[0004] The invention provides an improved technical framework for consent management, specifically addressing the need for: (i) Computationally efficient differential consent synchronisation; (ii) Secure, modularly indexed auditability through cryptographic metadata; (iii) Decentralised, cross-platform consent enforcement via independently verifiable cryptographic tokens; (iv) Immediate propagation of revocation events across distributed networks; (v) Efficient regulatory audit access to targeted historical consent records. These technical improvements enhance distributed system performance, cryptographic data integrity, secure interoperability, and resource efficiency beyond existing consent management systems. Solution Overview

[0005] The invention provides a modular consent management system comprising: • A Real-Time Consent Ledger (RTCL - 101), configured to compute differential consent updates, enabling minimal-data synchronisation and secure real-time propagation. • A Modular Metadata Audit System (MMAS - 102), designed to generate cryptographically linked audit records, indexed hierarchically for efficient audit queries. • A Cross-Platform Consent Token System (CCTS - 103), facilitating generation, validation, and revocation of portable cryptographic consent tokens across distributed platforms. • A Secure Integration Layer (104), ensuring authenticated and encrypted communication between all system modules. • A Consent Metadata Ledger (106), providing secure and persistent storage of structured audit records. • A User-Controlled Device (107), enabling users to initiate and manage consent-related actions.

[0006] Each component of the system addresses consent management challenges by enhancing data propagation efficiency, improving modular auditability, increasing network performance, and enabling decentralised consent enforcement in diverse digital environments. Summary of the Invention

[0007] The invention provides a computer-implemented consent management system for real-time consent synchronisation, structured auditability, and decentralised consent enforcement. It resolves existing limitations including high latency in consent propagation, inefficient audit trail management, and dependency on centralised enforcement mechanisms.

[0008] Referring to Figure 1, the system comprises three interconnected core modules: • Real-Time Consent Ledger (RTCL - 101); • Modular Metadata Audit System (MMAS - 102); • Cross-Platform Consent Token System (CCTS - 103). These modules communicate securely via a Secure Integration Layer (104) and interact with a persistent Consent Metadata Ledger (106). User consent actions are initiated and managed through a User-Controlled Device (107). Real-Time Consent Ledger (RTCL - 101)

[0009] The RTCL module calculates differential consent state updates, thereby minimising network data transfer. Instead of transmitting full consent records, it transmits only consent fields that have changed, significantly improving network efficiency and responsiveness.

[0010] Upon receipt of a consent update (201), the RTCL computes the difference (ACt\Delta C tACt) between the current consent state (CtC tCt) and the previous state (Ct-lC_{t-1 }Ct-l) using the equation: ACt=Ct-Ct-l\Delta C_t = C_t - C_{t-l}ACt=Ct-Ct-l Only the changes represented by (ACt\Delta C tACt) are propagated.

[0011] To ensure integrity, authenticity, and protection against replay attacks, a cryptographic validation hash is generated for each update using a one-way hash function (HHH): Validation Hash=H(ACt||Tt||Nonce)\text{Validation Hash} = H(\Delta C_t\parallel T_t \parallel \text{Nonce})Validation Hash=H(ACt||Tt||Nonce) where TtT tTt represents a timestamp and Nonce\text{Nonce}Nonce is a unique cryptographic random value.

[0012] Following cryptographic validation (203), consent updates undergo authentication (204) and are securely synchronised across all connected systems (205). The RTCL maintains up-to-date consent states (206) and incorporates a Real-Time Consent Revocation Algorithm (RCRA - 207). The RCRA ensures immediate consent revocation propagation, triggering synchronisation confirmations (208) to maintain accurate, compliant consent states. Figure 2 illustrates this consent data flow process clearly. Modular Metadata Audit System (MMAS - 102)

[0013] The Modular Metadata Audit System (MMAS - 102) generates structured and cryptographically linked metadata blocks, recording consent events such as grants, updates, and revocations. Upon detecting a consent event (301), MMAS creates a metadata block (302), linking it cryptographically to the preceding block using a Modular Metadata Audit Algorithm (MMAA - 303). The linking process uses the cryptographic hashing formula: Blocki=H(Blocki-l||Mi||Ti)\text{Block}_i = H(\text{Block}_{i-l} \parallel M i \parallel T_i)Blocki=H(Blocki-l IIMillTi) where Blocki\text{Block}_iBlocki is the hash value of the current metadata block, Blocki-l\text{Block}_{i-l }Blocki-l the previous block's hash, MiM iMi the metadata payload, and TiT iTi the timestamp of the consent event.

[0014] Metadata blocks are indexed hierarchically (304) by dimensions such as jurisdiction, datatype, or event identifiers (e.g., "Jurisdiction / DataType / EventID"). This indexing approach enables efficient, targeted audits and retrieval of specific historical consent data. Each cryptographically linked metadata block is stored securely in the append-only Consent Metadata Ledger (106).

[0015] Regulatory and authorised auditor access is provided via an Audit Interface (306), supported by a Metadata Verification engine (307), enabling verification of metadata provenance, authenticity, and integrity through cryptographic validation methods. Figure 3 illustrates the structured MMAS process. Cross-Platform Consent Token System (CCTS - 103)

[0016] The Cross-Platform Consent Token System (CCTS - 103) allows users to possess portable cryptographic tokens, representing their active consent preferences. Following validation of a consent update by the RTCL (101), a token generation request is initiated (401). The Consent Token Generation and Validation Algorithm (CTGVA - 402) constructs a cryptographically signed token according to: Token=Enc(Ct||IDU||ExpT)\text{Token} = Enc(C_t \parallel ID_U \parallel Exp_T)Token=Enc(Ct 11IDU11 ExpT) where EncEncEnc is a cryptographic signing or encryption function, CtC tCt represents the current consent state, IDUIDUIDU is a pseudonymised identifier for the user, and ExpTExp TExpT indicates the token's expiry timestamp. Optionally, the token may contain a scope-limiting field restricting consent validity to specific data categories or service domains, enabling selective revocation without affecting unrelated consents.

[0017] Once generated, the token is securely transmitted to and stored on the user's device (403). The user can then present this portable token to external platforms (404), which independently validate the token locally using public-key cryptography (405), thereby eliminating the need for continual queries to a central server and enabling decentralised enforcement.

[0018] Figure 5 details the consent token encryption, distribution, and independent validation handshake. If the user revokes consent (406), the RTCL promptly propagates the revocation event, triggering immediate invalidation of the affected token through the RCRA mechanism (407). This revocation procedure ensures outdated or revoked tokens cannot be misused, maintaining secure and timely consent state accuracy across systems. The full token lifecycle process is depicted clearly in Figure 4. Secure Integration Layer (104)

[0019] The Secure Integration Layer (104) ensures encrypted, authenticated communication across RTCL (101), MMAS (102), and CCTS (103). This layer utilises established cryptographic and communication security protocols, including: • Transport Layer Security (TLS), ensuring secure data exchange across network channels; • Digital signatures based on elliptic curve cryptography (ECC) or RSA algorithms, ensuring authenticity of messages; • Nonce-based challenge-response cycles, safeguarding message integrity and preventing replay attacks; • Regular session key rotation and ephemeral encryption methods, achieving forward secrecy.

[0020] This integration architecture protects against data interception, spoofing, and unauthorised access, preserving the confidentiality, integrity, and authenticity of all consent-related communications between system modules. Combined Operational Workflow

[0021] Figure 6 illustrates the integrated operational workflow. Initially, a user initiates a consent state change via their User-Controlled Device (601). The RTCL module processes this change as a differential update, performing validation (602). MMAS subsequently creates and stores the associated metadata audit block (603). CCTS generates and issues a portable consent token reflecting the new consent state (604). The user then presents this token to external platforms, which validate and enforce the consent preferences locally (605-606).

[0022] If consent revocation occurs (607), RTCL immediately propagates the revocation event (608). MMAS logs the revocation metadata block (609), and external platforms confirm and enforce the revocation promptly (610). This workflow ensures robust consent management, auditability, and real-time enforcement, addressing compliance requirements and operational reliability within distributed digital environments. Technical Benefits and Contribution

[0023] The invention delivers technical improvements over existing consent management technologies by providing: • Efficient synchronisation of user consent states via computationally optimised differential updates. • Verifiable consent auditability through cryptographically chained, modularly indexed metadata records. • Decentralised cross-platform enforcement of consent preferences enabled by portable cryptographic tokens capable of offline validation. • Immediate and secure propagation of consent revocation events across distributed platforms, ensuring timely invalidation of outdated consent states. • Effective compliance support for complex multi-jurisdictional privacy regulations and regulatory audit requirements.

[0024] Collectively, these advancements resolve core challenges related to consent propagation latency, inefficient audit record management, user data sovereignty, and decentralised consent enforcement reliability. Brief Description of Drawings

[0025] Embodiments of the invention are illustrated in the accompanying drawings, wherein identical reference numerals denote corresponding elements throughout: • Figure 1 - Overall System Architecture: A schematic representation illustrating the interactions among the core consent management modules: Real-Time Consent Ledger (RTCL - 101), Modular Metadata Audit System (MMAS - 102), Cross-Platform Consent Token System (CCTS - 103), Secure Integration Layer (104), External API Integration Module (105), Consent Metadata Ledger (106), and User-Controlled Device (107). Figure 2 - Real-Time Consent Ledger Data Flow (RTCL): A sequential operational diagram detailing the processes executed by the RTCL module: receipt of user-initiated consent changes (201), differential computation of consent state changes (202), cryptographic validation of updates (203), authentication of updates (204), secure propagation to interconnected systems (205), updating consent states (206), triggering consent revocations (207), and confirming distributed synchronisation (208). Figure 3 - Modular Metadata Audit Structure (MMAS): A functional schematic outlining the process for generating modular metadata blocks: detection of consent events (301), creation of metadata blocks (302), cryptographic chaining via the Modular Metadata Audit Algorithm (MMAA - 303), hierarchical indexing for targeted audits (304), secure metadata storage within the Consent Metadata Ledger (305), regulated access via an Audit Interface (306), and cryptographic verification of metadata (307). Figure 4 - Cross-Platform Consent Token Lifecycle (CCTS): A diagram illustrating the lifecycle management of portable consent tokens, comprising token generation requests (401), creation and signing of tokens via the Consent Token Generation and Validation Algorithm (CTGVA - 402), secure distribution of tokens to user devices (403), presentation of tokens to external platforms (404), independent local validation by platforms (405), user-triggered revocation of tokens (406), and subsequent immediate token invalidation via RTCL mechanisms (407). Figure 5 - Consent Token Encryption and Validation Handshake: A detailed cryptographic handshake diagram depicting consent token creation with encryption and digital signing (501), secure token distribution to the user's device (502), and independent validation of tokens by external platforms using public-key cryptography (503), enabling secure, decentralised, and stateless consent enforcement. Figure 6 - Example Operational Scenario (Integrated Workflow): A complete illustrative user journey demonstrating the integrated consent management workflow, including initiation of a consent state change (601), differential update processing by RTCL (602), metadata block creation by MMAS (603), token issuance by CCTS (604), token-based consent enforcement on external platforms (605-606), consent revocation by the user (607), immediate revocation propagation (608), revocation metadata logging (609), and final enforcement confirmation by all connected platforms (610). Detailed Description of the Invention

[0026] The invention comprises a modular system architecture for managing, auditing, and enforcing user consent across distributed digital environments. The system includes three core modules: a Real-Time Consent Ledger (RTCL - 101), a Modular Metadata Audit System (MMAS - 102), and a Cross-Platform Consent Token System (CCTS - 103). These modules communicate securely through a Secure Integration Layer (104), interact with external systems via an External API Integration Module (105), and store audit data securely within a persistent Consent Metadata Ledger (106). Consent actions are initiated by users through a User-Controlled Device (107). The overall system architecture is illustrated in Figure 1. Real-Time Consent Ledger (RTCL - 101)

[0027] The RTCL manages user consent state updates by computing differential updates rather than retransmitting entire consent datasets. When a user initiates a consent update via their device (107), the RTCL calculates a minimal differential update (ACt\Delta C tACt) defined by: ACt=Ct-Ct-l\Delta C_t = C_t - C_{t-l}ACt=Ct-Ct-l where CtC tCt represents the new consent state and Ct-lC_{t-l}Ct-l the previously recorded state. This differential approach ensures efficient data propagation and reduces network overhead.

[0028] To guarantee integrity and prevent replay attacks, the RTCL generates a cryptographic validation hash using a secure one-way hash function (HHH): Validation Hash=H(ACt||Tt||Nonce)\text{Validation Hash} = H(\Delta C_t\parallel T_t \parallel \text{Nonce})Validation Hash=H(ACt||Tt||Nonce) where TtT tTt is the associated timestamp and Nonce\text{Nonce}Nonce a unique cryptographic random value. This validation hash authenticates and verifies the freshness of consent state updates.

[0029] Upon successful cryptographic validation (203, Figure 2), the RTCL authenticates updates (204) and securely propagates the validated differential consent updates across all connected platforms (205). Consent states across the network are synchronised efficiently (206). The RTCL incorporates a Real-Time Consent Revocation Algorithm (RCRA - 207), ensuring immediate revocation and synchronisation confirmation across distributed systems (208). The full operational sequence of the RTCL module is illustrated in Figure 2. Modular Metadata Audit System (MMAS - 102)

[0030] The MMAS generates cryptographically secured metadata records for each consent event, including consent grants, updates, and revocations. Upon detection of a consent event (301, Figure 3), the system generates a metadata block (302). Each metadata block is linked cryptographically to the preceding block through the Modular Metadata Audit Algorithm (MMAA - 303), defined as: Blocki=H(Blocki—1 ||Mi||Ti)\text{Block}_i = H(\text{Block}_{i-l} \parallel Mi \parallel T_i)Blocki=H(Blocki-l IIMillTi) where Blocki\text{Block}_iBlocki is the cryptographic hash of the current metadata block, Blocki-l\text{Block}_{i-l }Blocki-l the hash of the previous block, MiMiMi the consent metadata payload, and TiTiTi the associated timestamp.

[0031] Each block is indexed using a hierarchical indexing scheme (304), structured by dimensions such as jurisdiction, data scope, and specific event identifiers—for example, "Jurisdiction / DataType / EventID". This indexing structure ensures efficient audit queries and targeted metadata retrieval.

[0032] Metadata blocks are stored securely within an append-only Consent Metadata Ledger (305). Authorised auditors access metadata records through a secure Audit Interface (306), supported by a Metadata Verification Engine (307) for cryptographic integrity checks. Figure 3 outlines the modular metadata audit structure clearly. Cross-Platform Consent Token System (CCTS - 103)

[0033] The CCTS module issues and manages portable cryptographic consent tokens representing users' active consent preferences. When a consent state update is confirmed by the RTCL, the CCTS initiates token generation (401, Figure 4). The Consent Token Generation and Validation Algorithm (CTGVA - 402) creates the token using the formula: Token=Enc(Ct||IDU||ExpT)\text{ Token} = Enc(C_t \parallel ID_U \parallel Exp_T)Token=Enc(Ct 11IDU11 ExpT) where EncEncEnc represents a cryptographic signing or encryption function, CtC tCt is the user's current consent state, IDUID UIDU is a pseudonymised user identifier, and ExpTExp TExpT is the token's expiry timestamp. Tokens can optionally include scopelimiting fields to allow selective revocation without affecting unrelated consents.

[0034] Tokens are securely distributed to and stored on the user's device (403), from which users present them to third-party platforms (404). External platforms independently validate token authenticity and enforce user-defined consent preferences locally (405) using publickey cryptography, without requiring continuous central validation queries.

[0035] When a user revokes consent (406), the RTCL immediately propagates this revocation event, triggering instant token invalidation through the RCRA mechanism (407). This approach ensures immediate revocation enforcement, preventing the misuse of invalidated tokens. Figure 4 illustrates the complete token lifecycle process. Secure Integration Layer (104)

[0036] The Secure Integration Layer (104) manages encrypted and authenticated communication between the Real-Time Consent Ledger (RTCL - 101), Modular Metadata Audit System (MMAS - 102), and Cross-Platform Consent Token System (CCTS - 103). The integration employs: • Transport Layer Security (TLS) protocols to encrypt data exchanges. • Digital signatures utilising elliptic curve or RSA cryptographic algorithms for message authenticity. • Nonce-based challenge-response cycles to protect message integrity and prevent replay attacks. • Session key rotation and ephemeral encryption methods to achieve forward secrecy.

[0037] This integration layer safeguards the system against data tampering, interception, and unauthorised access, thereby ensuring the confidentiality, integrity, and authenticity of communications across modules. Operational Scenario (Figure 6)

[0038] An illustrative consent management workflow sequence, represented in Figure 6, is as follows: • (601) User initiates a consent state change via their User-Controlled Device (107). • (602) RTCL calculates and validates the differential consent update. • (603) MM AS generates, cryptographically chains, and indexes a corresponding metadata block. • (604) CCTS generates and issues a portable consent token. • (605-606) The token is presented by the user to an external platform, which independently validates and locally enforces consent preferences. • (607) User initiates a consent revocation. • (608) RTCL immediately propagates revocation across all relevant platforms. • (609) MMAS logs the revocation event metadata block. • (610) Connected platforms confirm immediate enforcement of the revocation event.

[0039] This operational scenario demonstrates real-time synchronisation, decentralised enforcement capability, and cryptographically verifiable consent auditability, facilitating compliance and robustness in distributed environments. Specific Examples and Use Cases Example 1 - Healthcare Data Sharing with Hierarchical Metadata Indexing

[0040] A patient updates consent preferences through a hospital portal, granting permission to use imaging data for research but excluding it from insurance profiling. The patient initiates this consent change via their device (107, step 601). RTCL calculates the differential update (ACt) and performs cryptographic validation (602). MMAS creates and stores a corresponding metadata block, indexed hierarchically as "UK / health / imaging / research" within the Consent Metadata Ledger (106, step 603). CCTS generates a consent token, securely stored on the patient’s device (604). When presented at research institutions, the token is independently validated, and consent is locally enforced (605-606). Later, the patient revokes this consent; RTCL immediately propagates the revocation (607-608), MMAS records a revocation metadata block (609), and connected platforms immediately cease access (610). This example illustrates precise hierarchical audit indexing, consent synchronisation, and real-time decentralised enforcement in healthcare contexts. Example 2 - Cross-Jurisdictional Financial Data Consent

[0041] A UK-based user travelling in the UAE grants consent to a fintech application for transaction monitoring via their User-Controlled Device (107). RTCL processes the differential consent update, validating and synchronising it across systems (601-602). MMAS records a metadata block indexed as "UK / fmance / transactions" (603). CCTS generates a portable consent token valid for 14 days (604). The user presents this token to a UAE-based platform, where the platform independently validates and locally enforces the user's consent preferences (605-606). Upon the user's later revocation of consent, RTCL immediately propagates revocation (607-608), MMAS creates and logs the revocation block (609), and the connected platforms confirm and enforce revocation promptly (610). This example highlights cross-jurisdictional consent portability, efficient revocation processes, and decentralised validation. Example 3 - Consent Enforcement in Educational Platforms

[0042] A parent provides consent for their child's data to be shared with educational tools, defining subject-specific controls. Consent changes are initiated through a school-managed interface (107, 601). RTCL computes, validates, and synchronises the differential consent update (602). MMAS generates a metadata block indexed as "EU / education / STEM / primary" for targeted audit compliance (603). CCTS issues scoped consent tokens, each valid only for authorised applications or subjects (604). Educational platforms validate and enforce these tokens locally upon user presentation (605-606). Later, the parent revokes consent for one subject area; RTCL immediately propagates the revocation (607-608), MMAS logs the revocation event (609), and enforcement updates occur across relevant platforms without delay (610). This scenario demonstrates fine-grained consent enforcement, hierarchical indexing, and token-based modular consent control. Example 4 - Marketing Preference Management in E-Commerce

[0043] A user modifies cookie preferences on an international e-commerce platform to allow analytics while declining behavioural advertising. They update consent preferences through a digital interface (107, step 601). RTCL processes the consent state change as a differential update, validating and synchronising across relevant subdomains (602). MMAS creates a metadata block indexed as "EU / marketing / cookies / analytics" (603). CCTS issues a refreshed consent token reflecting the updated preferences (604). When accessing a marketing subdomain, the presented token is independently validated, enforcing the user's chosen restrictions on trackers (605-606). If the user subsequently revokes all marketing consent, RTCL promptly propagates the revocation event (607-608), MMAS appends a revocation metadata block linked to the initial event (609), and enforcement of this revocation is confirmed immediately across the platform (610). This illustrates layered consent management, precise audit indexing, and immediate revocation enforcement capabilities. Glossary of Terms Audit Interface (306): An interface within the MMAS allowing authorised auditors to query structured metadata records for compliance verification. Consent Delta (ACt): The minimal difference between sequential consent states (ACt = Ct - Ct-1), enabling efficient consent update synchronisation. Consent Metadata Ledger (106): A cryptographically secure, append-only ledger storing structured consent metadata audit blocks for regulatory compliance. Consent Token: A portable, cryptographically signed digital representation of a user's consent state, enabling independent decentralised enforcement. Consent Token Generation and Validation Algorithm (CTGVA): Algorithm generating and verifying cryptographic consent tokens as Token = Enc(Ct || IDU || ExpT), for secure decentralised enforcement. Cross-Platform Consent Token System (CCTS - 103): Module generating, distributing, validating, and revoking portable consent tokens across distributed platforms. Cryptographic Validation Hash: Hash generated by RTCL for secure authentication and integrity of differential consent updates, calculated as H(ACt || Tt || Nonce). Hierarchical Audit Index (304): Metadata indexing scheme categorising audit blocks for targeted regulatory audits. Modular Metadata Audit Algorithm (MMAA): Algorithm chaining metadata blocks cryptographically, calculated as Block i = H(Block_{i- 1} II M_i || T_i). Modular Metadata Audit System (MMAS - 102): Module generating cryptographically secured and hierarchically indexed consent audit metadata. Nonce: Unique random cryptographic value preventing replay attacks during consent transactions. Real-Time Consent Ledger (RTCL - 101): Module calculating and securely propagating differential consent state updates across distributed systems. Real-Time Consent Revocation Algorithm (RCRA): Algorithm ensuring immediate propagation and enforcement of user-initiated consent revocations. Secure Integration Layer (104): Communication layer using cryptographic protocols (TLS, digital signatures, nonce-based authentication) for secure inter-module integration. Token Expiry Timestamp (ExpT): Timestamp within consent tokens defining validity duration, enforcing automatic expiry. User-Controlled Device (107): Device operated by users to initiate, manage, and revoke consent preferences, and to present consent tokens. User Identifier (IDU): Pseudonymised identifier embedded within tokens and metadata for secure user identification and audit traceability.

Claims

System Claims1. A computer-implemented digital consent management system comprising:(a) a Real-Time Consent Ledger (RTCL - 101) configured to:o (i) receive user consent updates;o (ii) calculate delta updates (ACt = Ct - Ct-l), representing minimal consent state changes;o (iii) generate cryptographic validation hashes defined as H(ACt || Tt || Nonce), where H is a secure hash function, Tt is a timestamp, and Nonce is a cryptographic nonce;o (iv) securely synchronise validated delta updates across distributed platforms in real-time;(b) a Modular Metadata Audit System (MMAS - 102) configured to: o (i) generate modular metadata blocks recording each consent event;o (ii) cryptographically chain metadata blocks using a Modular Metadata Audit Algorithm (MMAA), defined as Blocki = H(Blocki-l || Mi || Ti), linking each new block explicitly to a previous block’s hash (Blocki-l), metadata payload (Mi), and timestamp (Ti);o (iii) index metadata blocks hierarchically by jurisdiction, data type, consent category, or timestamp to facilitate targeted audit retrieval;(c) a Cross-Platform Consent Token System (CCTS - 103) configured to:o (i) generate portable cryptographic consent tokens, explicitly structured as Token = Enc(Ct || IDU || ExpT), where Enc is a cryptographic signing or encryption function, Ct is the consent state, IDU is a pseudonymised user identifier, and ExpT is a token expiry timestamp;o (ii) enable independent validation of consent tokens by external platforms without centralised queries;o (iii) invalidate tokens immediately upon receipt of consent revocation notifications;(d) a Secure Integration Layer (104) configured to ensure encrypted, authenticated communication among RTCL, MMAS, and CCTS modules; and (e) a User-Controlled Device (107) configured for user initiation, management, and revocation of consent preferences.

2. The system of claim 1, wherein the Modular Metadata Audit Algorithm (MMAA) explicitly chains each metadata block using a cryptographic hash calculated from a previous block’s hash, the current block’s metadata payload, and a timestamp.

3. The system of claim 1 or claim 2, wherein the hierarchical audit indexing explicitly includes structured paths based on jurisdictional identifiers, data categories, consent event types, or timestamp data.

4. The system of any preceding claim, wherein the consent tokens are generated explicitly using the expression:Token = Enc(Ct || IDU || ExpT) where Enc explicitly denotes a cryptographic signing or encryption function.

5. The system of any preceding claim, wherein consent tokens explicitly include a scope-limiting field configured to enable selective consent revocation independently from unrelated permissions.

6. The system of any preceding claim, wherein the Secure Integration Layer explicitly utilises Transport Layer Security (TLS), RSA or elliptic curve digital signatures, nonce-based challenge-response protocols, and ephemeral encryption for forward secrecy and integrity.

7. The system of any preceding claim, wherein external platforms explicitly validate consent tokens independently, without ongoing reliance on centralised token verification services.

8. The system of any preceding claim, wherein user identifiers embedded within consent tokens are explicitly pseudonymised to ensure user privacy.

9. The system of any preceding claim, wherein the Consent Metadata Ledger is explicitly configured as a tamper-evident, append-only, cryptographically verifiable data store to maintain audit integrity.Method Claims10. A computer-implemented method for managing user consent across distributed digital platforms, comprising the steps of:(a) receiving a user consent state update request;(b) computing a delta update defined explicitly as ACt = Ct - Ct-l, representing minimal consent state changes;(c) generating a cryptographic validation hash using the delta update, a timestamp, and a cryptographic nonce;(d) securely synchronising the validated delta update across interconnected systems;(e) generating a modular metadata block recording the consent event details;(f) cryptographically chaining the modular metadata block explicitly to a preceding metadata block using a cryptographic hashing algorithm;(g) indexing metadata blocks explicitly and hierarchically according to jurisdiction, data category, consent event type, or timestamp;(h) storing the cryptographically chained and hierarchically indexed metadata blocks explicitly within an append-only Consent Metadata Ledger;(i) generating a portable cryptographic consent token explicitly comprising consent state information, a pseudonymised user identifier, and an expiry timestamp;(j) independently validating the consent token explicitly on third-party platforms without centralised queries;(k) immediately invalidating the consent token and explicitly logging a revocation metadata block upon receipt of a consent revocation event.

11. The method of claim 10, wherein consent tokens explicitly include scope-specific limitations enabling selective revocation of individual consent areas independently from other active consents.

12. The method of claim 10 or claim 11, wherein revocation events explicitly trigger immediate invalidation of affected tokens and result explicitly in cryptographically chained revocation metadata blocks stored in the Consent Metadata Ledger.

13. The method of any of claims 10 to 12, wherein modular metadata blocks explicitly include details such as consent event type, jurisdiction, data scope, pseudonymised user identifier, timestamps, and consent status information, facilitating explicit targeted audits and compliance verification.

14. The method of any of claims 10 to 13, wherein generated consent tokens are explicitly structured to enable independent validation by external platforms using explicit public-key cryptographic verification, allowing offline validation capability.

15. The method of any of claims 10 to 14, further explicitly comprising employing Transport Layer Security (TLS), cryptographic digital signatures, nonce-based integrity verification, and ephemeral key exchanges to secure inter-module communication.

16. The method of any of claims 10 to 15, further explicitly comprising periodic reviews of metadata block chains and hierarchical indices within the Consent Metadata Ledger for explicit compliance auditing and integrity validation.

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