Method and system for secure e-mail management with hardware-rooted encryption, verified deletion, and offline access

Abstract

The invention relates to a computer-implemented method and system for secure e-mail management, employing an indivisible sequence of interdependent modules, enabling automated downloading of messages and attachments via IMAP, POP3, proprietary or future-compatible protocols, authenticated through OAuth2 and mandatory multi-factor authentication (TOTP or FIDO2-compliant biometrics). Multi-layer integrity verification is performed prior to server deletion, using cryptographic checksums, error correction codes, and Merkle tree validation, generating immutable audit logs. The messages are stored locally in encrypted databases with hardware-bound keys managed by TPM, HSM, secure processor enclaves, or equivalents. Deletion is conditioned on multi-stage cryptographic verification and deletion tokens linked to audit logs; omission of any step invalidates the operation. Configurable grace periods with cross-device undo and an offline graphical interface are included, all inseparably integrated to ensure security, traceability and the technical compliance of the invention.

Description

[0001] Title: Method and system for secure email management with hardware-based encryption, verified deletion, and offline access

[0002] Inventor: Dr. Omar Gonzalez Santiago

[0003] Address: Hacienda los Lermas 2239, Misión del Valle Guadalupe, Nuevo León, Mexico, CP 67118.

[0004] Country: Mexico

[0005] Field of Invention

[0006] This invention belongs to the field of email management systems, and more specifically to computer-implemented methods and systems that optimize email storage through an indivisible and strictly interdependent sequence of operations: automated and secure download, hardware-secured encrypted local storage, verified remote deletion, and efficient offline access to messages, where each step is essential to achieving the claimed technical effect and depends on the correct execution of all preceding steps. The invention addresses cryptographic lifecycle management, multi-device synchronization with conflict resolution, and tamper-proof auditing capabilities essential for enterprise compliance, which are unattainable by previous systems if the components operate in isolation.The sequence produces a non-trivial technical effect that cannot be achieved by state-of-the-art systems, even if each component is known individually.

[0007] The invention solves a technical problem not addressed by conventional systems: irreversible data loss due to post-verification corruption during multi-device synchronization. This is achieved through a hardware-enforced individual sequence where deletion tokens are invalidated unless all devices confirm integrity using vector clocks and Merkle tree validation. Background of the Invention

[0008] Storage limitations imposed by email service providers necessitate either purchasing additional capacity or deleting emails. Existing email clients and backup solutions often lack built-in, inseparable mechanisms for secure deletion contingent upon verified local backup integrity. Mobile applications typically prioritize cloud synchronization over freeing up server space.

[0009] There is a critical need for an indivisible and interdependent system that automates the secure download of emails with multi-stage verification before deletion, uses hardware-secured encryption (including hardware-equivalent secure elements), allows offline querying of messages, and provides controlled and verified deletion with user-configurable grace periods and undo capabilities, where all these processes are essential and cannot operate independently.

[0010] Existing systems do not combine hardware-backed deletion tokens with real-time error correction, leading to irretrievable data loss if corruption occurs on the server after deletion. The invention's nested verification (SHA-3 + Reed-Solomon + Merkle trees) ensures recoverability while maintaining evidence of tampering, a capability demonstrably absent in the prior art.

[0011] This invention also contributes to environmental sustainability by reducing reliance on remote cloud storage and the energy consumption associated with data centers. By enabling secure and verified local storage of emails and attachments, it minimizes the demand for server storage resources, reducing the energy consumption associated with data hosting, cooling, and network infrastructure. Furthermore, optimized compression and offline access decrease repetitive network traffic, further reducing energy consumption. Efficient management of electronic communications helps reduce the overall carbon footprint associated with email storage and retrieval. These benefits illustrate a tangible technical effect that further differentiates the invention from previous implementations.

[0012] Summary of the Invention

[0013] The invention provides a computer-implemented method and system that:

[0014] Free up space on the email server while preserving full offline access to the content of locally stored emails through an indivisible sequence of dependent operations;

[0015] Store emails in AES-256, ChaCha20, post-quantum or equivalent encrypted databases, or in secure file systems, with encryption keys protected by TPM 2.0, HSM, hardware biometric security or equivalent hardware secure elements, where each storage step is inseparably linked to previous verification and subsequent deletion stages, ensuring that no step operates independently;

[0016] It performs multi-stage integrity verification using cryptographic checksums, error detection / correction codes, and a nested verification structure that combines SHA-3 checksums for headers, Reed-Solomon encoding for message bodies, and Merkle roots by integrating previous layers and synchronization metadata, such that omitting or bypassing any stage automatically prevents deletion, demonstrating technical interdependence;

[0017] Delete messages from the mail server only after successful verification, secure local storage using hardware-linked keys with anti-export protection, mandatory generation of cryptographic deletion tokens, and synchronization of vector clocks between devices, where all steps are functionally linked to ensure secure and verifiable deletion;

[0018] It provides a secure offline interface with hardware-backed biometric authentication, accelerated full-text search, export, and cryptographically signed audit logs, where offline access and auditing mechanisms are inseparably coupled to the verification and deletion sequence;

[0019] Synchronize delete and undo operations between devices using vector clocks, logical clocks or equivalents, reinforcing that consistency between devices depends on prior verification and secure storage;

[0020] Implements FIDO2 biometric authentication with liveness detection;

[0021] Generates tamper-proof audit logs, structured as Merkle trees;

[0022] It includes functional equivalents, distributed implementations, and reordering of steps only if logical dependencies and interdependent effects are preserved, emphasizing the indivisible inventive sequence of operations.

[0023] Although state-of-the-art systems address individual aspects of email security, deletion, or local storage, such as secure email transmission (US20060053280A1), hardware-linked key management via HSM (US20130179676A1, US10893057B2), and automated message deletion (US6324569B1, US7783715B2), none provides the claimed indivisible sequence of interdependent modules that ensures secure downloading, multi-layered integrity verification, hardware-enforced local encryption, verifiable deletion, offline access, and cross-device synchronization in a strictly dependent manner. The combination of these elements produces a technical effect that cannot be achieved by any subset of independently implemented components: secure and verifiable email management with tamper-proof auditing, conditional deletion, and consistent offline availability.This demonstrates that the invention is not obvious to a person skilled in the art, since conventional systems cannot achieve the same integrated functionality without violating the claimed interdependent sequence.

[0024] Consolidated Technical Results and Benefits:

[0025] 1. Server and Cloud Space Optimization

[0026] Secure local storage of messages and attachments reduces the load on remote server storage while maintaining full access for the user.

[0027] 2.- Safety Verified Before Disposal

[0028] Deletion occurs only after successful completion of integrity checks, encryption, and hardware attestation, preventing accidental or unauthorized deletion.

[0029] 3. Multi-Device Consistency

[0030] Synchronization using vector clocks ensures a consistent state across all devices, preventing desynchronization or data loss.

[0031] 4. Tamper-Evident Audit

[0032] All actions are recorded in signed Merkle trees, providing full traceability and immediate tamper detection.

[0033] 5.- Reduction of Network Traffic and Energy Consumption Offline access and local search minimize dependence on the cloud and data transfer, decreasing bandwidth usage and energy consumption.

[0034] 6. Prevention of Unauthorized Disposal

[0035] Cryptographically conditional deletion tokens are issued only when all multilayer verification stages are successful, ensuring controlled message deletion.

[0036] 7.- Cryptographically Applied Grace and Undo Period

[0037] Grace periods and undo functionality are implemented securely so that they cannot be circumvented without violating the integrity of records and tokens.

[0038] Detailed Description of the Invention

[0039] System Architecture

[0040] The system establishes secure connections to email servers using IMAP, POP3, proprietary protocols, or compatible future protocols, authenticated using OAuth2 with mandatory two-factor authentication mechanisms such as TOTP or FIDO2 biometric verification. Emails, including content, metadata, and attachments, are downloaded incrementally with integrity verification using SHA-256, SHA-3, or equivalent cryptographic checksums, and CRC32 or Reed-Solomon error detection / correction codes. Attachments are compressed using user-selectable lossless algorithms (LZMA, Zstandard, or equivalent) to optimize storage.

[0041] All data is stored locally in AES-256, ChaCha20, post-quantum, or equivalent encrypted databases, or in secure file systems, with encryption keys securely managed by TPM 2.0, external HSMs, biometric hardware security elements, or equivalent hardware or virtualized secure modules. Any deletion operation requires the inseparable execution of multi-stage verification, including Merkle tree validation for metadata, Reed-Solomon checks for attachments, and generation of cryptographic deletion tokens; omission of any step invalidates the deletion. Any equivalent secure storage or key management solution that achieves substantially the same tamper resistance and key isolation is included, and any attempt to circumvent or bypass these mechanisms constitutes a violation.

[0042] The user interacts with a secure offline interface that enables fast, accelerated full-text search using preprocessed indexes by WebAssembly or functional equivalents, message preview and export, and access to cryptographically signed audit logs. Any alternative implementation that provides substantially the same functionality in an equivalent manner, including CLI, API, mobile, web, or hybrid interfaces, is included.

[0043] Equivalents and Scope of Implementation

[0044] Any functional equivalent that achieves substantially the same results in a substantially equivalent manner, in any environment or platform (including on-premises, distributed, virtualized, or cloud-based systems), is expressly included. Any reimplementation, modification, substitution, or decoupling of essential step interdependencies (including, without limitation, enabling deletion without multilayer verification, circumventing hardware-bound encryption, using virtual HSMs without FIPS 140-3 or equivalent certification, altering verification, integrity, or encryption steps, or changing critical operational sequences) is expressly excluded from equivalence and constitutes a clear and direct infringement. Any attempt to replicate, emulate, or approximate the claimed functionality in a substantially similar manner, even partially, will likewise be considered an infringement. Additional Paragraph for Coverage Extension

[0045] For the purposes of this disclosure, the indivisibility of steps and modules includes distributed, cloud-based, virtualized, or multi-device implementations, provided that the logical sequence and interdependence of the claimed operations are preserved. Multi-layered nested verification architectures, cryptographic deletion tokens, and hardware-bound key policies are inseparably linked to the execution sequence. Step reordering is included if logical dependencies and results are maintained. Any attempt to omit, circumvent, or replace steps, modules, or operations while achieving the same results is considered a violation.

[0046] Hardware-linked key storage includes both physical and hardware equivalents, including virtualized implementations, provided they offer substantially the same tamper resistance and key isolation capabilities. Policies enforcing anti-export, anti-migration, and biometric authentication with liveness detection are included. The grace period mechanism is inextricably linked to verification and synchronization, such that deletion or circumvention of the grace period disables deletion capabilities and constitutes a violation.

[0047] Although individual components such as SHA-3 checksums, Reed-Solomon error correction codes, Merkle tree audit logs, hardware-bound key storage (TPM, HSM, or equivalent secure elements), and multi-factor authentication are known in the prior art, the claimed indivisible sequence of interdependent modules produces a technical effect that cannot be achieved by any subset of these components executed in isolation. This unique combination ensures secure and verifiable deletion, hardware-enforced local storage, and tamper-proof audited offline access, achieving results that conventional email clients or backup systems cannot. Any attempt to circumvent, omit, or reimplement individual steps without preserving the logical dependencies would fail to deliver the claimed technical benefits, thus demonstrating the non-obviousness of the invention.

[0048] Data Recovery and Integrity Protocols

[0049] Interrupted downloads are automatically retried using an exponential backoff algorithm, with a maximum of three attempts; any equivalent retry or failover method is included.

[0050] Partial downloads are preserved and resumed using Reed-Solomon error correction codes to maintain data integrity under adverse network conditions; any alternative error correction or integrity preservation methods are included.

[0051] Multi-layered integrity verification ensures data correctness: cryptographic sums verify message content; parity bits and Reed-Solomon codes facilitate error correction; Merkle tree structures guarantee tamper-proof audit log integrity. Any alternative verification, logging, or tamper evidence mechanism that achieves substantially the same result is included.

[0052] Process Flow

[0053] Secure authentication to the mail server using OAuth2 and two-factor authentication (TOTP, FIDO2 or equivalent).

[0054] Automated incremental download of emails and attachments with real-time integrity verification.

[0055] Message integrity is verified before any deletion operation; failure to verify integrity halts deletion. Local storage is encrypted with key protection using TPM 2.0, HSM, biometric hardware, hardware equivalent modules, or functional equivalents.

[0056] Conditional deletion of emails from the server after successful verification and explicit user confirmation or expiration of a configurable grace period; deletion depends on successful synchronization and verification.

[0057] Secure offline interface that enforces biometric or PIN authentication, providing accelerated full-text search, message preview, export functions, and access to tamper-proof audit logs.

[0058] Synchronization of deletions and undo operations between devices using vector clocks, logical clocks, or equivalent conflict resolution mechanisms.

[0059] FIDO2 biometric authentication application with liveness detection.

[0060] Generation and maintenance of cryptographically signed audit logs, integrated into Merkle trees.

[0061] Any module, system, or method that substantially achieves the same functions or results, including distributed or cloud-based implementations, is included.

Claims

Claims Independent Claim of Method 1. A computer-implemented method for the secure management of email, comprising an indivisible and strictly interdependent sequence of steps, each of which is essential to achieve the claimed technical effect: (a) Establish a secure authenticated connection to the email server using one or more email access protocols, including IMAP, POP3, proprietary or future compatible protocols, and authenticate to the mail server using OAuth2 with mandatory FIDO2 biometric liveness detection, where failure of authentication blocks all subsequent steps of accessing, downloading, processing or offline viewing of emails. (b) Download emails and attachments with multi-layered, real-time integrity verification: (i) SHA-3 hashes for headers, (i) Reed-Solomon bug fixes for message bodies, (iii) Merkle roots integrating (i), (i) and cross-device synchronization metadata; incrementally downloading messages including content, metadata and attachments with integrity verification during transfer. (c) Verify the integrity of each downloaded message using one or more cryptographic or error-detection mechanisms, including SHA-256, SHA-3, CRC32, Reed-Solomon or functional equivalents, where each verification step depends strictly on the successful execution of subsequent operations and cannot be independently substituted without loss of the claimed technical effect. (d) Store verified messages locally in an encrypted database or secure file system, where encryption keys are managed by a hardware security module, trusted processor enclave, biometric authentication, or equivalent secure hardware or virtualized elements. (e) Delete one or more messages from the email server only after: (i) Successful completion of all verification stages, including nested verification combining SHA-3 sums for headers, Reed-Solomon encoding for bodies, and Merkle root signatures for both data and synchronization metadata, (i) Secure local storage with hardware-linked keys implementing anti-export and anti-migration policies, (iii) Explicit user confirmation or expiration of a configurable grace period inseparably linked to the verification and removal steps, and (iv) Successful synchronization of the deletion state across all linked devices and generation of a cryptographic deletion token containing a Merkle root and verifiable timestamp; wherein omission or alteration of any sub-step irreversibly stops the deletion process and prevents the claimed method from delivering its secure and verifiable deletion capability as designed, emphasizing the indivisible and strictly interdependent inventive sequence. (f) Index messages locally for offline search and retrieval. (g) Provide a secure graphical interface that allows searching, previewing, exporting and accessing cryptographically signed audit logs, which are only verifiable when generated by the claimed sequence. (h) Any functional equivalent, replacement, modification or reimplementation of any step, module or combination of steps that substantially performs the the same functions in a substantially equivalent manner, including distributed, cloud-based or virtualized implementations, is understood, and any attempt to circumvent, omit or alter steps constitutes infringement; the inventive aspect lies in the non-obvious, strictly interdependent combination of all steps, each of which is essential to produce a technical effect not achievable by any subset executed in isolation. Method-Dependent Claims 1g. The verification stage employs a layered, nested architecture where SHA-3 hashes secure email headers, Reed-Solomon codes protect message bodies, and a Merkle root combines all layers along with synchronization metadata. This arrangement, using Merkle leaves to integrate SHA-3 and Reed-Solomon parity, forms a structure not previously implemented in email clients. This can reduce latency by 40–60%, depending on message size and synchronization frequency. Any modification, omission, or reimplementation that disrupts this layered dependency invalidates the verification and constitutes a violation. 1 h. The method of claim 1, wherein failure of any verification step automatically blocks deletion operations on all devices and generates an integrity failure state recorded in an immutable audit trail.

1. Hardware-based encryption key storage implements a physical linking policy including TPM PCR linking, biometric authentication with liveness detection for removal and anti-migration enforcement even between instances of the same security module; no purely software-based or inferior security solution can replace it without loss of the claimed tamper resistance effect. lj. In claim 1, the audit log integrity check is performed prior to deletion, cryptographically linked to the message content, and failure of this check blocks all subsequent operations in the sequence. Any attempt to circumvent this is included. lk. In claim 1, the sequence remains within scope even if individual steps are distributed across multiple software applications, processes, devices, or execution environments, provided that logical dependencies are maintained and no step is operative without the completion of all required preceding steps. ll. In claim 1, execution on remote servers, cloud-based services, hybrid environments, or third-party infrastructure is included, provided that all claimed steps are performed in the claimed logical sequence. lm.In claim 1, the reordering of steps while preserving logical dependencies and functional results is considered within the scope. In claim 1, hardware-bound key storage includes physical security modules, virtualized secure elements or software equivalents, or any secure element that provides tamper resistance and key isolation functionally equivalent to a physical module, where such equivalence is measured by the impossibility of extracting keys without destruction or detection. In claim 1, the grace period mechanism is inextricably linked to verification and synchronization, such that removing the grace period disables the deletion functionality, and any attempt to circumvent this mechanism is included.

1. In claim 1, the grace period may be optionally applied by means of a smart contract or automated mechanism, ensuring automatic invalidation if synchronization fails, while preserving the indivisible and strictly interdependent sequence of the claimed method. Independent System Claim A system implemented on a user device for secure email management, comprising: A secure connection module for mail servers that supports multi-factor authentication, including OAuth2, TOTP, FIDO2 or equivalent; A download module with multi-level integrity verification that is inoperable without prior establishment of a secure connection; An encrypted local storage module or secure file system protected by a hardware security module, trusted processor enclave, biometric key management, or equivalent hardware or virtualized secure elements; An indexing engine optimized for offline full-text search that indexes only messages verified and stored using the claimed sequence; A secure graphical interface that supports searching, previewing, exporting, and accessing signed audit logs, the validity of which depends on the integrity of all preceding modules; where all modules operate in an interdependent and inseparable sequence so that no module can perform its core function without the successful execution of the preceding modules, providing a non-trivial technical effect that cannot be achieved by the independent operation of conventional modules; Any combination of the above modules or functional equivalents that perform substantially the same functions in a substantially equivalent manner, including distributed, cloud-based, or virtualized implementations, and any attempt to omit, circumvent, or alter modules constitutes infringement. All modules must achieve the following: • Tamper-proof audit logs with <1 ms latency for Merkle tree updates, • Error correction capable of recovering 100% of data under 5% packet loss, • Hardware-enforced deletion tokens with cryptographic linkage to TPM / HSM attestation, where any system that does not meet these criteria infringes this claim. System-Dependent Claims 11a. Local storage may include any encrypted database, file system, or alternative storage capable of offline access and integrity verification, and any functional equivalent that provides substantially the same security and verifiability is included. 11 b. Integrity verification employs a hybrid model that combines: (a) conventional cryptographic signatures for headers, (b) perceptual hash to detect manipulation of image attachments, (c) An optimized Merkle tree for large attachments (>10MB). This hybrid scheme reduces verification time by 40-60% compared to standard methods, and each verification subcomponent depends on the results of the others to complete the process. Any attempt to circumvent these verifications constitutes a violation. llc. Deletion and synchronization may occur via LAN, Wi-Fi, VPN, hybrid cloud, or any equivalent communication method that achieves the same results; all functional equivalents and alternative communication methods are included. lld. The offline interface may include CLI, API, web, mobile, or any equivalent interface that provides substantially the same user experience; any modification or replacement that substantially achieves the same function is included. 11 e. Any combination of modules or functional equivalents that perform substantially the same combination of operations is deemed to be within the scope of the invention, provided that such equivalents maintain the strict functional interdependence required for the claimed technical effect, and any attempt to circumvent, omit, or alter interdependent modules constitutes infringement. 11f. Core functional modules may be deployed in separate software or hardware components, across multiple devices or in cloud-based services, remaining within the scope of the claimed interdependent sequence; any reimplementation that preserves logical dependencies is understood. 11 g. Execution on remote, hybrid or virtualized infrastructure is included, provided that the sequence of claimed operations is preserved; any equivalent functional deployment is also included. 11 h. The order of execution of the modules may be altered without going out of scope, provided that all logical dependencies are maintained, and any attempt to circumvent the interdependent sequence is prohibited. 11 i. Hardware-based encryption key storage comprises both physical modules and hardware-equivalent virtualized secure elements with equivalent tamper resistance and isolation; any functional equivalent that meets these requirements is included. 11 j. The grace period mechanism is inseparably linked to the verification and synchronization logic, so disabling the grace period disables the deletion capability; attempts to reimplement the mechanism without this link are out of scope and are considered a violation.