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Latest case studyBridging Tari to Ethereum: WXTM & Secure Tokenization
Bridging Tari to Ethereum: WXTM & Secure Tokenization
Tari is an innovative L1 protocol focused on digital assets and privacy-preserving smart contracts. As a relatively new blockchain entering the crypto landscape, Tari faced a critical challenge: how to integrate their native XTM tokens with the broader DeFi ecosystem to enable trading, liquidity provision, and participation in decentralized finance protocols.
Collaboration timeframe:2 months
Services:Blockchain Development, Smart Contract Development, DevOps, Full-Stack Development
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A hybrid of a social network and a music app
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The first truly decentralized stablecoin crypto on Ethereum
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An identity verification MVP
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What Connects Poseidon to X-Ray: A Deep Dive into ZKP on Stellar_BlogPostImageWhat Connects Poseidon to X-Ray: A Deep Dive into ZKP on Stellar
Oskar.jpg_BlogPostAuthorAvatarBy Oskar Karcz
Welcome back! Seriously, welcome back, because we’re diving into the world of Zero-Knowledge Proofs (ZKP) once again. But this time, we’re looking at it from a fresh angle: the Stellar blockchain perspective. I must admit, I was surprised by how beautifully this blockchain already supports ZKP - and their plans for the future are even more ambitious. So, if the clickbait title piqued your curiosity about what connects the God of the Sea (Poseidon) to medical imaging (X-ray), stay with me until the end. Grab a coffee, and let's explore elliptic curves, hash functions, and the magic of host functions. ## ZKP and Stellar: A Match Made in Heaven I’ve already written a few articles about ZKP (like [ZKP Overview Part 2](https://www.rumblefish.dev/blog/post/the-current-state-of-knowledge-about-zero-knowledge-comprehensive-private-token-overview-part-2/) or [ZKP Overview Part 3](https://www.rumblefish.dev/blog/post/the-current-state-of-knowledge-about-zero-knowledge-comprehensive-private-token-overview-part-3/)), so before we dive in, please check those out to make sure you’re familiar with the basics. Or, you can ask your Agentic AI (oh look, [I wrote about that too!](https://www.rumblefish.dev/blog/post/agentic-ai/)) to explain keywords like circuits, Circom language, and proof generation/verification. Let’s learn more about Stellar. They introduce themselves as  _“an open-source blockchain used for a variety of payment and remittance applications.”_ It’s a wide net, but the most interesting Stellar feature for us right now is how it supports ZKP, and how we can write smart contracts that utilize this facet. The Stellar network has a smart contract platform called Soroban. Smart contracts here are written in Rust and compiled to WebAssembly (Wasm) for deployment ([source](https://developers.stellar.org/docs/build/smart-contracts/overview)). That’s enough for us to know at the moment, but if you’re interested in getting your hands dirty with Soroban, check out the [Getting started guide](https://developers.stellar.org/docs/build/smart-contracts/getting-started). Not so long ago, in 2024, Stellar took a quantum leap toward adopting advanced ZKP systems by [adding support for the **BLS12-381 elliptic curve**](https://github.com/stellar/rs-soroban-env/issues/779). But what exactly do I mean by “adding support”? To understand this, let’s take a quick detour into the world of host functions. ## Host Functions: The Captain and the Nav-Computer Let’s use a space-themed analogy (we are talking about Stellar, after all). Imagine your smart contract is the Captain of a starship. If the Captain needs to open a sliding door or turn on the lights (simple smart contract logic), they do it easily. It consumes almost no energy. But imagine the Captain needs to calculate a hyper-jump trajectory through a moving asteroid field (that’s the heavy ZKP math). If the Captain tried to calculate this by hand using a pencil and paper on the bridge, it would take weeks, burn through all the ship's life support reserves (gas fees), and the ship would likely crash before the answer was found. A host function is like using the ship’s dedicated Nav-Computer. The Captain doesn't do the math manually; they just punch in the destination and hit "Calculate." The ship’s mainframe (the Stellar nodes) runs the complex physics equations instantly using highly optimized hardware circuits. The Captain still decides where to go (the logic), but the heavy lifting is offloaded to the machine built specifically for speed. In technical terms, the "Nav-Computer" is the pre-compiled, native machine code running on the node, which is infinitely faster than the "Captain" trying to run math inside the constrained Wasm environment. Generally speaking, every blockchain has its own unique set of host functions (often called "precompiles," "syscalls," or "native programs"). Think of them like the operating system APIs for that specific blockchain. ### BLS12-381… So, back to the main topic: "adding support" meant adding host functions for BLS12-381 and its underlying field arithmetics. In simple terms: "Now you can play around with ZKP on Stellar!" Wooooow, isn’t that awesome? But if you opened the GitHub issue link I shared earlier ([this one,](https://github.com/stellar/rs-soroban-env/issues/779) cheers if you did!), you might have read: “The most widely used pairing friendly curve is BN254 (...) due to the fact that Ethereum has support for it.” Wait. What is BN254? Why was BLS12-381 chosen first? AND WHY DO THESE NAMES LOOK SO RANDOM? Let’s take another detour to talk about elliptic curves. ### … and BN254 At their core, elliptic curves are specific mathematical structures, essentially complex algebra equations graphed as curves, that allow computers to perform cryptographic tasks like signing transactions or verifying proofs extremely efficiently. The names BN254 and BLS12-381 might look random, but they are scientific labels: "BN" and "BLS" stand for the researchers who discovered the curve families (Barreto-Naehrig and Barreto-Lynn-Scott), while the numbers describe precise parameters like the size of the prime numbers used to build them. Think of these two curves as incompatible types of mathematical railroad tracks designed for the heavy lifting of Zero-Knowledge proofs. * **BN254** (aka \`alt\_bn128\`) acts like a "legacy" high-speed rail line from around 2015. It was adopted early by Ethereum, making it the standard track for thousands of existing applications because it is lightweight and cheap to run. However, later research found its security walls (about 100-bit) to be slightly thinner than originally intended. * **BLS12-381** is the modern, heavy-duty freight line designed for long-term safety. It offers the gold-standard 128-bit security preferred by newer networks like Zcash and Ethereum 2.0. This extra armor means its keys are larger and its operations require slightly more computational power. Because a proof written for one curve is mathematically unreadable by the other, Stellar's decision to support both is like building a station that can service both the older, widespread commuter trains and the newer, heavy-armored security transports. This ensures developers don't have to rebuild their entire fleet just to switch networks. ## X-RAY: The Protocol Upgrade That Changes Everything So, did Stellar make the right decision by implementing BLS12-381 first and not BN254? Yes and no. Yes, for the security reasons I mentioned above. No, because right now (Jan 2026), implementing support for BN254 is… actively in progress! But why? As explained in [_CAP-0074: Host functions for BN254_](https://github.com/stellar/stellar-protocol/blob/master/core/cap-0074.md) (CAP stands for Core Advancement Proposals): _“While Stellar has native support for BLS12-381, many existing applications still rely on BN254 because it's the only pairing-friendly elliptic curve with native support in the EVM. Adding BN254 support will allow those applications to add support for Soroban without the need to use a different curve.”_ Without native Soroban support for BN-254, developers building ZK apps on Stellar would have to either rewrite their applications or maintain complex workarounds. Supporting both gives developers the flexibility to choose the curve that best suits their goals. In Nov 2025, the Stellar Team announced an upcoming protocol upgrade called X-Ray. This upgrade proposes native support not only for BN254 but also for another important ZK primitive: Poseidon! ## Poseidon: The Hash Function Built for Zero-Knowledge Poseidon is a family of hash functions designed specifically for ZKP systems. As the article states: _“While BN254 provides the pairing operations for proof verification, you also need an efficient cryptographic hash, which is where Poseidon comes in. (...) These primitives let developers design hash functions that are highly efficient in ZK circuits, addressing a key performance bottleneck in ZK systems.”_ Traditional hashes like SHA-256 are computationally expensive to model within proofs. Poseidon is like a sports car built specifically for the ZK racetrack. And again, adding support for it means adding a host function to Soroban. This was introduced in [CAP-0075: Cryptographic Primitives for Poseidon/Poseidon2 Hash Functions.](https://github.com/stellar/stellar-protocol/blob/master/core/cap-0075.md) ## Why This Matters? This perfect duo, **CAP-0074** and **CAP-0075,** establishes the rock-solid cryptographic foundation developers have been waiting for. It allows us to build privacy-preserving applications on Stellar without compromising the transparency that makes blockchain so powerful. So, what does this actually unlock for us? (Glad you asked!): * **Smooth Sailing:** Migrating existing ZK apps becomes a walk in the park. * **Turbo Efficiency:** Proof systems become faster, leaner, and more powerful. * **Wallet-Friendly:** We’re talking significantly lower costs for ZK-based contracts. * **The Big Bridge:** It opens a massive gateway to the broader ZK ecosystem, inviting everyone to the party. I hope this (zero-) knowledge unlocks your curiosity and willingness to give Stellar a try with your new ZKP project. I’ve already tried it and can’t wait to see both CAPs live on mainnet! In the meantime, stay tuned, and as always, [reach out to us if you have any questions.](mailto:hello@rumblefish.dev) See you next time!
Blockchain
Agentic AI: Your Code’s License to Kill (Tasks)_BlogPostImageAgentic AI: Your Code’s License to Kill (Tasks)
Oskar.jpg_BlogPostAuthorAvatarBy Oskar Karcz
Lately, we've been discovering all the different flavors of blockchain technology - from the nitty-gritty of XRP Hooks to the complex machinery of Solana's indexers. But this time, let’s switch gears a little bit to explore another amazing and rapidly growing universe: AI. We’ve moved from simply chatting with AI to watching it write code, debug errors, and even browse the web. But are we really maximizing this potential? Is typing into a prompt box really the peak of evolution? I don't think so! Today, we’re going to step into the next frontier: Agentic AI. If you’ve ever felt like your favorite chatbot is brilliant but lazy, waiting for you to do all the copy-pasting, this article is for you. So, grab a massive cup of coffee, find a comfy spot to read, and let’s dive into the world of autonomous agents! ## The Name’s AI. Agentic AI. Let’s be honest. "Agentic AI" sounds a bit like a buzzword salad, doesn't it? But stick with me. To understand what this actually is, we need to leave the boring server room and head to the movies. Think of a standard LLM (like GPT-4 or Claude) as “M” from the James Bond movies. M is incredibly smart, has access to all the intelligence files, and sits safely in an office in London. M can tell you what to do, analyze the situation, and give you a strategy. But M doesn’t leave the desk. M can’t drive the Aston Martin, and M certainly can’t defuse the bomb. In the tech world, Agentic AI is an artificial intelligence system that acts just like 007. It has the same intelligence as M (the LLM brain), but it also has a License to Kill (Tasks). It’s not just generating text; it’s taking action in the real world (or at least, the digital world). It has permission to use "gadgets" (tools), make decisions on the fly, and execute missions without phoning home for every single step. ### The 00-Section: A Team of Agents OK, so Agentic AI is an artificial intelligence system that can accomplish a specific goal with limited supervision. But you know what the cool thing is? Agentic AI isn't just a lone wolf running wild. Often, it’s not just one Bond, but a whole squad of 00-specialists. In a multi-agent system, you have individual agents - machine learning models that mimic human decision-making - where each one performs a specific subtask required to reach the goal. Think of it like a heist movie: one agent is the driver, another is the hacker, and another is the safe-cracker. Their efforts are coordinated through **AI orchestration** to solve problems in real-time. ## GenAI vs. Agentic AI: The Lab vs. The Field _"But wait a sec,"_ I can hear you asking, _"isn't this just ChatGPT with a fancy new marketing name?"_ Excellent question! But the answer is a resounding no. Let’s distinguish the two. Think of traditional Generative AI (GenAI) as Q’s laboratory. It’s fantastic at creating things based on learned patterns. It can manufacture a gadget, write a dossier, or generate a code snippet. It focuses on outputting content. Agentic AI, on the other hand, is the agent taking that gear into the field to do stuff. It extends the capability of GenAI by applying those outputs toward specific goals. * **GenAI:** Can tell you the best time to climb Mt. Everest based on your work schedule. * **Agentic AI:** Will look at your schedule, access a travel API, book your flight to Nepal, reserve a hotel room, and maybe even order you a pair of thermal socks. See the difference? **One chats, the other acts.** Unlike traditional models that operate within predefined constraints and wait for you to click "enter," Agentic AI exhibits goal-driven behavior. It looks at the objective, figures out the steps, and executes them by calling external tools. So, why is this the new hotness? Because we are moving from the era of "Chatbots" to the era of "Actionbots". * **Autonomy:** They don't need you to babysit them. * **Adaptability:** If the flight to Nepal is cancelled, a good agentic system figures out an alternative route rather than just throwing an error message. * **Orchestration:** You can chain complex workflows together that used to require a human project manager. It’s about to get very interesting for developers who want to build systems that don't just think but actually work. ## The Double-Edged Sword Unfortunately, real life isn’t quite like the movies. We aren't yet in that luxurious position where we can just sit back, relax, and watch our agents handle everything for us. Giving an AI a "License to Act" comes with risks. If 007 goes rogue, buildings explode. If your Agentic AI gets stuck in an infinite loop while using a paid API... well, your credit card bill explodes. Threats? * _**Infinite Loops:**_ The agent keeps trying to solve a problem it can't solve, burning tokens like there's no tomorrow. * _**Hallucinations in Logic:**_ The agent _thinks_ it saved the file, but it actually just wrote a print statement saying it did. This is why "Human-in-the-loop" is still a massive concept in this space. Sometimes, even Bond needs to call M for authorization before launching the missile. ## Mission Debrief That’s it! We’ve taken a journey from the passive desk-job LLMs to the action-packed world of Agentic AI. We’ve seen how giving models "gadgets" and a "reasoning loop" turns them into autonomous operators capable of complex workflows. The technology is still young, and the frameworks (like LangChain or CrewAI) are evolving faster than a car chase scene. But the potential? Limitless. If you are curious about how to implement these agents in your own stack, or how to orchestrate a fleet of them to handle complex logic (maybe even on-chain?), keep your eyes peeled for our next updates. As always, feel free to jump into our repositories or [reach out to the team](mailto:hello@rumblefish.dev) if you have any questions. Until next time, keep your code clean and your agents licensed!
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