The goal of NGI Assure is to support projects that design and engineer reusable building blocks for the Next Generation Internet as part of a complete, strong chain of assurances for all stakeholders regarding the source and integrity of identities, identifiers, data, cyberphysical systems, service components and processes. Furthermore contributions can be made to address underlying real-world challenges in deploying and validating such building blocks, such as energy efficiency and sustainability, scalability and throughput, security, privacy/confidentiality, plausible deniability, robustness and crypto-agility, side-channel resistance, interoperability, governance and compliance to regulatory frameworks – where needed to turn the above into reproducible and trustworthy end-to-end solutions that can withstand the hostile battle grounds of the modern internet. NGI Assure is looking for building blocks that contribute to providing such assurances include (but are not limited to) quantum-proof cryptography, public key infrastructure, (augmented) authenticated key exchange, ratchet mechanisms (such as the Noise protocol) that securely chain key material, distributed hash tables and DAGs to make P2P interaction more secure, conflict-free replicated data types, mixnets and onion routing mechanisms, consensus protocols, distributed ledgers and (post) blockchain technologies that create redundant data sets managed independently by mutually distrustful parties, a priori usage control, symbolic and formal proofs, and tamperproof open hardware implementations of core cryptographic primitives. We are looking for deep tech components; the outcomes of NGI Assure shall contribute towards identifying and solving current issues, but do not need to provide a complete solution by themselves (although they may).