Harvest Now, Decrypt Later: How Imperva Protects TLS Sessions with Post-Quantum Cryptography

Imperva Enables Post-Quantum TLS in Cloud WAF: Immediate Protection Without Configuration

Imperva has implemented hybrid post-quantum TLS 1.3 on every connection between users and its Cloud WAF network, offering immediate protection against "harvest now, decrypt later" (HNDL) attacks without requiring any configuration from customers. The solution combines classic algorithms with encryption resistant to quantum computers, automatically activatable on compatible systems.

Quick Answer

Hybrid X25519MLKEM768 TLS Active by Default

Every TLS 1.3 connection from a PQC-compatible client to Imperva now negotiates a hybrid key agreement: X25519MLKEM768. This combines the classic algorithm X25519 with the secure quantum key encapsulation mechanism ML-KEM-768, standardized by NIST with FIPS 203 in August 2024. The functionality is enabled by default on all Imperva sites, without measurable performance trade-offs.

End-to-End Protection with Origin Support

As of the October 4, 2026 update, Imperva also supports PQC in the connection between its network and the customer's origin. Customers with origin servers that support the hybrid key agreement thus obtain secure end-to-end encryption, from the user's browser to their infrastructure. The minimum requirement is having OpenSSL 3.5 or later versions, which offer X25519MLKEM768 by default.

Seamless Implementation

Sites created on or after October 4, 2026 have PQC to the origin enabled by default. For existing sites, the feature must be manually activated via the SSL/TLS configuration or the /v3/sites/origin-pqc API. If the origin does not support the hybrid key agreement, the connection reverts to classic TLS without interruption. Users can verify PQC protection by opening Chrome DevTools and checking the Security panel.

Complete Protection Against HNDL Attacks

The hybrid key agreement protects the confidentiality of every session, neutralizing the harvest now, decrypt later attack. However, certificate signing requires a separate migration (NIST ML-DSA, FIPS 204), as forging a signature requires a quantum computer at the time of key negotiation. Data recorded by attackers does not offer attack vectors at this stage.

Reduction of Operational Costs for Compliance

For regulated sectors such as finance, healthcare, and defense, this implementation transforms a complex security program into a simple compliance statement. Imperva eliminates the need for premium SKUs, site-level enablement, or migration projects, significantly reducing the operational overhead for compliance with the NIS2 Directive and the DORA Regulation.

Verification and Activation of PQC

For customers, the process is simple: verify that the origin supports OpenSSL 3.5 or later versions and enable PQC to the origin via the Cloud Security console or the API. Technical details, including testing methods and activation procedures, are available in the Imperva PQC documentation. For new sites created after October 4, 2026, PQC to the origin is enabled by default.

Impact on Corporate Security

Imperva's implementation represents a significant step toward corporate security in a post-quantum era. Companies that need to protect sensitive data for decades, such as banks, hospitals, and government agencies, can now state that all sessions through Cloud WAF are secure by default. This significantly simplifies relationships with auditors and board presentations, reducing risks related to cyber insurance.

Future Prospects for Post-Quantum Cryptography

As the industry gradually adopts post-quantum TLS, Imperva stands out for its pragmatic approach. The solution seamlessly integrates with zero-trust architectures, offering an additional layer of enterprise cloud security. Protection against HNDL attacks is particularly relevant for organizations managing critical data, where sensitive data protection must extend beyond the time horizon of classical computers.