{"id":48970,"date":"2025-08-26T11:00:30","date_gmt":"2025-08-26T08:00:30","guid":{"rendered":"https:\/\/coinengineer.net\/blog\/?p=48970"},"modified":"2025-08-26T10:59:35","modified_gmt":"2025-08-26T07:59:35","slug":"what-is-citrea","status":"publish","type":"post","link":"https:\/\/coinengineer.net\/blog\/what-is-citrea\/","title":{"rendered":"What is Citrea?"},"content":{"rendered":"<p>In the world of cryptocurrency, <strong>Bitcoin<\/strong> is indisputably the leader in terms of security and decentralization. However, increasing user interest and transaction demands have exposed Bitcoin\u2019s scalability issues. Rising transaction fees and block space limitations make it difficult to develop more complex applications on Bitcoin.<\/p>\n<p><strong>Citrea<\/strong> is the first Bitcoin rollup project to address this problem using zero-knowledge proofs (ZK-proofs). By leveraging Bitcoin as both a settlement layer and a data availability layer, Citrea enhances on-chain verifiability. This allows the construction of more complex and scalable applications without compromising Bitcoin\u2019s security.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-48972 aligncenter\" src=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-48-07-300x141.jpg\" alt=\"\" width=\"1091\" height=\"513\" srcset=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-48-07-300x141.jpg 300w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-48-07-1024x481.jpg 1024w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-48-07-768x361.jpg 768w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-48-07.jpg 1280w\" sizes=\"auto, (max-width: 1091px) 100vw, 1091px\" \/><\/p>\n<div id=\"ez-toc-container\" class=\"ez-toc-v2_0_71 counter-hierarchy ez-toc-counter ez-toc-grey ez-toc-container-direction\">\n<div class=\"ez-toc-title-container\">\n<p class=\"ez-toc-title\" style=\"cursor:inherit\">Table of Contents<\/p>\n<span class=\"ez-toc-title-toggle\"><a href=\"#\" class=\"ez-toc-pull-right ez-toc-btn ez-toc-btn-xs ez-toc-btn-default ez-toc-toggle\" aria-label=\"Toggle Table of Content\"><span class=\"ez-toc-js-icon-con\"><span class=\"\"><span class=\"eztoc-hide\" style=\"display:none;\">Toggle<\/span><span class=\"ez-toc-icon-toggle-span\"><svg style=\"fill: #999;color:#999\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" class=\"list-377408\" width=\"20px\" height=\"20px\" viewBox=\"0 0 24 24\" fill=\"none\"><path d=\"M6 6H4v2h2V6zm14 0H8v2h12V6zM4 11h2v2H4v-2zm16 0H8v2h12v-2zM4 16h2v2H4v-2zm16 0H8v2h12v-2z\" fill=\"currentColor\"><\/path><\/svg><svg style=\"fill: #999;color:#999\" class=\"arrow-unsorted-368013\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\" width=\"10px\" height=\"10px\" viewBox=\"0 0 24 24\" version=\"1.2\" baseProfile=\"tiny\"><path d=\"M18.2 9.3l-6.2-6.3-6.2 6.3c-.2.2-.3.4-.3.7s.1.5.3.7c.2.2.4.3.7.3h11c.3 0 .5-.1.7-.3.2-.2.3-.5.3-.7s-.1-.5-.3-.7zM5.8 14.7l6.2 6.3 6.2-6.3c.2-.2.3-.5.3-.7s-.1-.5-.3-.7c-.2-.2-.4-.3-.7-.3h-11c-.3 0-.5.1-.7.3-.2.2-.3.5-.3.7s.1.5.3.7z\"\/><\/svg><\/span><\/span><\/span><\/a><\/span><\/div>\n<nav><ul class='ez-toc-list ez-toc-list-level-1 eztoc-toggle-hide-by-default' ><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-1\" href=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#Key_Features_of_Citrea\" title=\"Key Features of Citrea\">Key Features of Citrea<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-2\" href=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#Funding_and_Investor_Support\" title=\"Funding and Investor Support\">Funding and Investor Support<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-3\" href=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#Citreas_Founding_Team\" title=\"Citrea\u2019s Founding Team\">Citrea\u2019s Founding Team<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-4\" href=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#Scalability_Challenges_Faced_by_Bitcoin\" title=\"Scalability Challenges Faced by Bitcoin\">Scalability Challenges Faced by Bitcoin<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-5\" href=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#Execution_Layer_That_Transforms_Sidechains\" title=\"Execution Layer That Transforms Sidechains\">Execution Layer That Transforms Sidechains<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-6\" href=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#Useful_Information\" title=\"Useful Information\">Useful Information<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-7\" href=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#Bitcoin_as_the_Foundation_for_Applications\" title=\"Bitcoin as the Foundation for Applications\">Bitcoin as the Foundation for Applications<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-8\" href=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#Timeline\" title=\"Timeline\">Timeline<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-9\" href=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#Logic\" title=\"Logic\">Logic<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-10\" href=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#EVM_Equivalence\" title=\"EVM Equivalence\">EVM Equivalence<\/a><\/li><li class='ez-toc-page-1 ez-toc-heading-level-2'><a class=\"ez-toc-link ez-toc-heading-11\" href=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#Citreas_Mission\" title=\"Citrea\u2019s Mission\">Citrea\u2019s Mission<\/a><\/li><\/ul><\/nav><\/div>\n<h2><span class=\"ez-toc-section\" id=\"Key_Features_of_Citrea\"><\/span>Key Features of Citrea<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<ol>\n<li data-start=\"83\" data-end=\"359\">The First Rollup Solution for Bitcoin<br data-start=\"127\" data-end=\"130\" \/>Citrea is the first rollup solution implemented in the Bitcoin ecosystem. This model, commonly used in the Ethereum ecosystem, aggregates thousands of transactions into a single batch, increasing scalability and reducing costs.<\/li>\n<li data-start=\"361\" data-end=\"589\">EVM Compatibility<br data-start=\"385\" data-end=\"388\" \/>Citrea is fully compatible with the Ethereum Virtual Machine (EVM). This allows developers who are already building on Ethereum to port their applications to the Bitcoin network with minimal changes.<\/li>\n<li data-start=\"591\" data-end=\"736\">Two-Way Peg with BitVM and Clementine<br data-start=\"635\" data-end=\"638\" \/>Citrea uses a trustless, zero-knowledge proof-supported two-way peg mechanism called Clementine.<\/li>\n<\/ol>\n<p data-start=\"738\" data-end=\"833\">This setup allows users to transfer Bitcoin to Citrea (peg-in) or withdraw it back (peg-out).<\/p>\n<p data-start=\"835\" data-end=\"1002\">With BitVM integration, bridge operations are executed with minimized trust. Unlike traditional federation-based bridges, only a single honest validator is required.<\/p>\n<ol start=\"4\">\n<li data-start=\"1004\" data-end=\"1232\">On-Chain Data Availability<br data-start=\"1037\" data-end=\"1040\" \/>Citrea leverages Bitcoin\u2019s block space to provide on-chain data availability. This ensures a more efficient transaction process while preserving Bitcoin\u2019s censorship resistance and security.<\/li>\n<\/ol>\n<h2 data-start=\"1234\" data-end=\"1335\"><span class=\"ez-toc-section\" id=\"Funding_and_Investor_Support\"><\/span>Funding and Investor Support<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p data-start=\"1234\" data-end=\"1335\">Citrea has quickly attracted attention from prominent investors:<\/p>\n<ul>\n<li data-start=\"1339\" data-end=\"1470\">Seed Round: $2.7 million raised, led by Galaxy, with participation from Delphi Ventures, Eric Wall, Anurag Arjun, and others.<\/li>\n<li data-start=\"1473\" data-end=\"1598\">Series A: $14 million raised, led by Founders Fund, with participation from Maven 11, Mirana Ventures, and other funds.<\/li>\n<\/ul>\n<p data-start=\"1600\" data-end=\"1710\">These investments demonstrate confidence in both Citrea\u2019s technical infrastructure and its long-term vision<\/p>\n<p data-start=\"1600\" data-end=\"1710\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-48973 aligncenter\" src=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-49-50-300x126.jpg\" alt=\"\" width=\"1064\" height=\"447\" \/><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Citreas_Founding_Team\"><\/span>Citrea\u2019s Founding Team<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p data-start=\"83\" data-end=\"155\">Citrea is being developed by Chainway Labs. The core team consists of:<\/p>\n<ul>\n<li data-start=\"159\" data-end=\"178\">Orkun Mahir K\u0131l\u0131\u00e7<\/li>\n<li data-start=\"181\" data-end=\"198\">Esad Yusuf Atik<\/li>\n<li data-start=\"201\" data-end=\"218\">Murat Karademir<\/li>\n<\/ul>\n<p data-start=\"220\" data-end=\"300\">The team members have many years of experience in blockchain and cryptography.<\/p>\n<p data-start=\"220\" data-end=\"300\"><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-48974 aligncenter\" src=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-50-29-300x44.jpg\" alt=\"\" width=\"1064\" height=\"156\" srcset=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-50-29-300x44.jpg 300w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-50-29-1024x151.jpg 1024w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-50-29-768x113.jpg 768w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-50-29.jpg 1071w\" sizes=\"auto, (max-width: 1064px) 100vw, 1064px\" \/><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Scalability_Challenges_Faced_by_Bitcoin\"><\/span>Scalability Challenges Faced by Bitcoin<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>High Demand and Rising Fees: Bitcoin\u2019s growing popularity has created intense competition for block space, driving up transaction fees.<\/p>\n<p>Limited Transaction Capacity: Due to Bitcoin\u2019s limited block size, not all transactions can fit into the blockchain.<\/p>\n<p>Shortcomings of Existing Solutions: While Layer-2 solutions like the Lightning Network are effective for payments, they fall short for DeFi and complex applications. Sidechains, on the other hand, cannot provide the same security guarantees as Bitcoin.<\/p>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone  wp-image-48975\" src=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-51-15-300x115.jpg\" alt=\"\" width=\"1062\" height=\"407\" srcset=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-51-15-300x115.jpg 300w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-51-15.jpg 766w\" sizes=\"auto, (max-width: 1062px) 100vw, 1062px\" \/><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Execution_Layer_That_Transforms_Sidechains\"><\/span>Execution Layer That Transforms Sidechains<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>In the Bitcoin ecosystem, sidechains have long been used to address scalability issues. These sidechains enable additional applications and faster transactions while preserving Bitcoin\u2019s security and core consensus rules. However, traditional sidechains have some critical limitations:<\/p>\n<ul>\n<li>Security Trade-Offs: Most sidechains do not offer Bitcoin\u2019s full security. Users often rely on additional federations or trust-based participants for transaction validation.<\/li>\n<li>Off-Chain Transaction Complexity: Since sidechains are not directly integrated with the Bitcoin blockchain, they lack full data availability and on-chain verifiability.<\/li>\n<li>Monolithic Structures: Traditional sidechains typically operate as a single execution layer and lack modularity, making it difficult for more complex applications to run securely on Bitcoin.<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-48976 aligncenter\" src=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-52-07-300x151.jpg\" alt=\"\" width=\"1061\" height=\"534\" srcset=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-52-07-300x151.jpg 300w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-52-07-768x386.jpg 768w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-52-07.jpg 1000w\" sizes=\"auto, (max-width: 1061px) 100vw, 1061px\" \/><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Useful_Information\"><\/span>Useful Information<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Citrea is the only execution layer that performs transactions directly on Bitcoin. Every transaction on Citrea is fully secured using zero-knowledge proofs and verified by Bitcoin. Citrea\u2019s execution environment is trustless relative to Bitcoin and accessible to all participants on the Bitcoin network. Therefore, Citrea maintains the same guarantees for data availability, censorship resistance, and reorganization resistance as Bitcoin.<\/p>\n<h2><span class=\"ez-toc-section\" id=\"Bitcoin_as_the_Foundation_for_Applications\"><\/span>Bitcoin as the Foundation for Applications<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Citrea\u2019s mission is to create a programmable liquidity layer on Bitcoin, the most secure and decentralized blockchain. We believe that Bitcoin\u2019s block space should be efficiently used to handle various financial activities such as trustless BTC purchases, leveraging BTC, or lending BTC. While most existing meta-protocols attempting to provide these functions are trust-based and inefficient, Citrea is the most secure and efficient platform for building applications on Bitcoin.<\/p>\n<p>Bitcoin Consensus and Trust-Minimized Two-Way Peg<\/p>\n<p>Citrea implements the first trust-minimized two-way peg mechanism via Clementine, protected by ZK proofs and BitVM. As long as a single validator in the BitVM setup is honest, Clementine remains secure. This represents a significant improvement over current solutions (such as open or closed federations).<\/p>\n<p>The design of Clementine, combined with Citrea\u2019s trustless light client, minimizes the trust requirements for a two-way peg without requiring soft forks. The core components of Clementine include light client proofs (for both Bitcoin and Citrea) and ZKP validators in BitVM. The core process is as follows:<\/p>\n<ul>\n<li>BitVM-Based In-Peg and Out-Peg<br \/>\nClementine allows only statically-sized UTXOs for in-peg and out-peg transfers. For simplicity, assume exactly 1 BTC.<\/li>\n<li>In-Peg Logic<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-48977 aligncenter\" src=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-53-22-300x141.jpg\" alt=\"\" width=\"1060\" height=\"498\" srcset=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-53-22-300x141.jpg 300w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-53-22-1024x482.jpg 1024w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-53-22-768x361.jpg 768w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-53-22.jpg 1280w\" sizes=\"auto, (max-width: 1060px) 100vw, 1060px\" \/><\/p>\n<p>In-Peg Logic<br \/>\nTo initiate a peg, the user locks 1 BTC in a UTXO that can only be accessed by the following parties: an N+1-of-N+1 multisig (N\u20131 validators, the bridge operator, and the user) or the user retrieves the funds after 200 blocks. After locking the UTXO, the user sends the transaction signature to the validators.<\/p>\n<p>Once the transaction on Bitcoin is completed, the funds are transferred to a new N-of-N multisig. The user can mint their pegged BTC on Citrea by presenting an SPV proof to the smart contract. The transaction includes an EVM address used to identify the user on Citrea.<\/p>\n<ul>\n<li>Out-Peg Logic<br \/>\nTo initiate a withdrawal, the user must transfer 1 BTC to a smart contract on Citrea and provide a Bitcoin address. This address is recorded as a new leaf in the \u201cWithdrawal Merkle Tree,\u201d and the 1 BTC is then burned on Citrea. For simplicity, we can assume each Bitcoin address is unique, though this is not a strict requirement. Therefore, any transfer of 1 BTC to a specific Bitcoin address on the Bitcoin network results in a valid withdrawal.<\/li>\n<li>Binding Source: UTXO<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-48978 aligncenter\" src=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-54-36-300x229.jpg\" alt=\"\" width=\"1060\" height=\"809\" srcset=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-54-36-300x229.jpg 300w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-54-36-1024x782.jpg 1024w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-54-36-768x587.jpg 768w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-54-36.jpg 1280w\" sizes=\"auto, (max-width: 1060px) 100vw, 1060px\" \/><\/p>\n<p>UTXO Principle<\/p>\n<p>Clementine ensures that if the bridge operator tries to claim more BTC than the covered withdrawal amount, they will permanently lose access to the bridge funds.<\/p>\n<p>The Connector Source UTXO is used by the operator to make claims from Clementine. To gain access to the Binding Source UTXO, the operator uses a Binding UTXO tree\u2014essentially a UTXO tree that the operator relies on to prove the amount of BTC they can legitimately claim for the covered withdrawals.<\/p>\n<ul>\n<li>Two-Way Peg Scheme<\/li>\n<\/ul>\n<h2><span class=\"ez-toc-section\" id=\"Timeline\"><\/span>Timeline<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-48979 aligncenter\" src=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-55-26-300x49.jpg\" alt=\"\" width=\"1059\" height=\"173\" srcset=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-55-26-300x49.jpg 300w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-55-26-1024x166.jpg 1024w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-55-26-768x124.jpg 768w\" sizes=\"auto, (max-width: 1059px) 100vw, 1059px\" \/><\/p>\n<ul>\n<li data-start=\"71\" data-end=\"153\">Light Client Deadline: BitVM commitment checks block height for withdrawals.<\/li>\n<li data-start=\"156\" data-end=\"266\">Submission Period: Time allocated for the operator to cover remaining withdrawals and record pre-images.<\/li>\n<li data-start=\"269\" data-end=\"463\">K-deep Assumption: Ensures finality of the latest Bitcoin block. Since validators may dispute the PoW of the latest block, the operator cannot use different block hashes for private forks.<\/li>\n<li data-start=\"466\" data-end=\"923\">BitVM Challenge Response Period: Period in which validators challenge the operator and enter an interactive verification game if necessary. At the end of this period, only two outcomes are possible:<br data-start=\"668\" data-end=\"671\" \/>The Binding Source UTXO is available for the operator to use, allowing them to claim the covered BTC during withdrawals.<br data-start=\"796\" data-end=\"799\" \/>b. The Binding Source UTXO is burned along with the BitVM response UTXO, revoking the operator\u2019s access to bridge funds.<\/li>\n<\/ul>\n<p data-start=\"925\" data-end=\"1027\">The light client checkpoint occurs every six months and continues indefinitely at the same interval.<\/p>\n<h2 data-start=\"1029\" data-end=\"1040\"><span class=\"ez-toc-section\" id=\"Logic\"><\/span>Logic<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p data-start=\"1042\" data-end=\"1409\">In Clementine, once the proof\u2014including withdrawals\u2014is finalized on Bitcoin, the operator is responsible for covering each withdrawal. After each period, the operator reveals the log\u2082(n) pre-images on Bitcoin, committing the amount of bridge funds claimed from Clementine. This amount equals the total withdrawals covered since the last checkpoint of the pre-image.<\/p>\n<h2 data-start=\"1411\" data-end=\"1432\"><span class=\"ez-toc-section\" id=\"EVM_Equivalence\"><\/span>EVM Equivalence<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p data-start=\"1434\" data-end=\"1981\">Citrea brings programmability to Bitcoin through the Ethereum Virtual Machine (EVM). Citrea\u2019s EVM is zero-knowledge verifiable and customized for Bitcoin and BitVM. This execution environment allows users to deploy complex smart contracts beyond Bitcoin\u2019s native scripting capabilities. Citrea scales Bitcoin by batching thousands of transactions and generating compact validity proofs. Citrea proofs are written on Bitcoin and can be optimistically verified on Bitcoin via BitVM. This model ensures on-chain data availability and verifiability.<\/p>\n<ul>\n<li data-start=\"1983\" data-end=\"2001\">User Deposit<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-48980 aligncenter\" src=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-56-30-300x251.jpg\" alt=\"\" width=\"1059\" height=\"886\" srcset=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-56-30-300x251.jpg 300w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-56-30-768x642.jpg 768w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-56-30.jpg 785w\" sizes=\"auto, (max-width: 1059px) 100vw, 1059px\" \/><\/p>\n<p>When a user sends BTC to the bridge operator, the pegging process begins. Validators (participants with the authority to challenge the bridge operator) then sign the user\u2019s transaction. This signature is presented to the bridge operator, indicating that the validators have confirmed the BTC deposit. Once this verification step is complete, the user can mint cBTC (CitreaBTC) on Citrea by submitting the SPV (Simplified Payment Verification) of the transaction to the smart contract in exchange for BTC sent to the deposit address controlled by BitVM.<\/p>\n<p>Alternatively, the user can enter Citrea via an atomic swap using Bitcoin or the Lightning Network, which is easier and cheaper than using the two-way peg deposit.<\/p>\n<ul>\n<li>Transaction Process<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"wp-image-48981 aligncenter\" src=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-57-16-300x98.jpg\" alt=\"\" width=\"1059\" height=\"346\" srcset=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-57-16-300x98.jpg 300w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-57-16.jpg 763w\" sizes=\"auto, (max-width: 1059px) 100vw, 1059px\" \/><\/p>\n<p>Citrea\u2019s EVM environment enables applications such as DeFi, private transfers, or BTC-for-BTC swaps. Regardless of the user\u2019s application, the technical process begins when the user submits a transaction to a full node. Once received, the full node forwards it to the sequencer for provisional confirmation. Anyone accessing Citrea\u2019s transaction history or query data can set up a full Citrea node.<\/p>\n<p>The sequencer is a full node that softly confirms transactions and produces blocks. These soft confirmations (soft blocks) are then propagated to every full node. The purpose of soft confirmations is to provide users with a fast transaction experience. The next step involves a specialized full node called a prover, responsible for zero-knowledge aggregation, which plays a critical role in inheriting user transaction security from Bitcoin.<\/p>\n<p>Like all full nodes, the prover receives soft sequencer confirmations and stores the data. The key difference is that the prover aggregates the softly confirmed transactions into batches. It then generates a zero-knowledge proof that anyone can use to verify the validity of the batch.<\/p>\n<p>The prover also creates a dataset called a state diff, representing the difference between the initial state and the latest state. The creation of the state diff explains why Citrea is efficient in using Bitcoin block space. Since Bitcoin block space is limited and costly, Citrea stores the state diff instead of full transaction data to minimize block space usage and data costs.<\/p>\n<ul>\n<li>User Withdrawal Process<\/li>\n<\/ul>\n<p><img loading=\"lazy\" decoding=\"async\" class=\"alignnone  wp-image-48982\" src=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-58-03-300x168.jpg\" alt=\"\" width=\"1059\" height=\"593\" srcset=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-58-03-300x168.jpg 300w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-58-03-768x430.jpg 768w, https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/photo_2025-08-26_11-58-03.jpg 772w\" sizes=\"auto, (max-width: 1059px) 100vw, 1059px\" \/><\/p>\n<h2><span class=\"ez-toc-section\" id=\"Citreas_Mission\"><\/span>Citrea\u2019s Mission<span class=\"ez-toc-section-end\"><\/span><\/h2>\n<p>Citrea aims to transform Bitcoin from being merely a store of value into a programmable financial ecosystem. This allows Bitcoin to become the hub for DeFi, NFTs, decentralized exchanges (DEXs), and next-generation financial products.<\/p>\n<p>Citrea provides an innovative solution to Bitcoin\u2019s scalability challenges using zero-knowledge technology. Its EVM compatibility enables Ethereum developers to easily build on Bitcoin, while the Clementine bridge mechanism ensures secure asset transfers.<\/p>\n<p>With strong investor support, a clear technical vision, and an experienced founding team, Citrea has the potential to become the primary choice for those looking to develop applications on Bitcoin in the coming years.<\/p>\n<ul class=\"darkmysite_processed\" data-darkmysite_preserved_bg=\"rgb(16, 18, 19)\" data-darkmysite_preserved_color=\"rgb(16, 19, 20)\">\n<li class=\"darkmysite_processed\" dir=\"ltr\" data-darkmysite_preserved_bg=\"rgb(16, 18, 19)\" data-darkmysite_preserved_color=\"rgb(16, 19, 20)\"><a href=\"https:\/\/citrea.xyz\/\">Websitesi<\/a><\/li>\n<li class=\"darkmysite_processed\" dir=\"ltr\" data-darkmysite_preserved_bg=\"rgb(16, 18, 19)\" data-darkmysite_preserved_color=\"rgb(16, 19, 20)\"><a href=\"https:\/\/x.com\/citrea_xyz\">X (Twitter)<\/a><\/li>\n<li class=\"darkmysite_processed\" dir=\"ltr\" data-darkmysite_preserved_bg=\"rgb(16, 18, 19)\" data-darkmysite_preserved_color=\"rgb(16, 19, 20)\"><a href=\"https:\/\/discord.com\/invite\/citrea\">Discord<\/a><\/li>\n<\/ul>\n<p>You can also freely share your thoughts and comments about the topic in the comment section. Additionally, don\u2019t forget to follow us on our\u00a0<a class=\"darkmysite_style_txt_border darkmysite_style_link darkmysite_processed\" href=\"https:\/\/t.me\/coinengineernews\" target=\"_blank\" rel=\"nofollow noopener\" data-darkmysite_alpha_bg=\"rgba(0, 0, 0, 0)\"><strong class=\"darkmysite_style_txt_border darkmysite_processed\" data-darkmysite_alpha_bg=\"rgba(0, 0, 0, 0)\">Telegram,\u00a0<\/strong><\/a><a class=\"darkmysite_style_txt_border darkmysite_style_link darkmysite_processed\" href=\"https:\/\/www.youtube.com\/@CoinEngineer\" target=\"_blank\" rel=\"nofollow noopener\" data-darkmysite_alpha_bg=\"rgba(0, 0, 0, 0)\"><strong class=\"darkmysite_style_txt_border darkmysite_processed\" data-darkmysite_alpha_bg=\"rgba(0, 0, 0, 0)\">YouTube<\/strong><\/a>,\u00a0and\u00a0<a class=\"darkmysite_style_txt_border darkmysite_style_link darkmysite_processed\" href=\"https:\/\/twitter.com\/coinengineers\" target=\"_blank\" rel=\"nofollow noopener\" data-darkmysite_alpha_bg=\"rgba(0, 0, 0, 0)\"><strong class=\"darkmysite_style_txt_border darkmysite_processed\" data-darkmysite_alpha_bg=\"rgba(0, 0, 0, 0)\">Twitter<\/strong><\/a>\u00a0channels for the latest\u00a0<a class=\"darkmysite_style_txt_border darkmysite_style_link darkmysite_processed\" title=\"News\" href=\"https:\/\/coinengineer.net\/blog\/news\/\" data-internallinksmanager029f6b8e52c=\"7\" data-darkmysite_alpha_bg=\"rgba(0, 0, 0, 0)\">news<\/a>\u00a0and updates.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the world of cryptocurrency, Bitcoin is indisputably the leader in terms of security and decentralization. However, increasing user interest and transaction demands have exposed Bitcoin\u2019s scalability issues. Rising transaction fees and block space limitations make it difficult to develop more complex applications on Bitcoin. Citrea is the first Bitcoin rollup project to address this<\/p>\n","protected":false},"author":37,"featured_media":48971,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,657,2],"tags":[236,192,393,5384,840,847,58,501],"class_list":["post-48970","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-crypto-news","category-en","category-news","tag-altcoin","tag-blockchain","tag-crypto","tag-crypto-investment","tag-crypto-market","tag-crypto-news","tag-cryptocurrency","tag-investment"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v22.6 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>What is Citrea?<\/title>\n<meta name=\"description\" content=\"In the world of cryptocurrency, Bitcoin is indisputably the leader in terms of security and decentralization. However, increasing user\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/\" \/>\n<meta property=\"og:locale\" content=\"en_US\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"What is Citrea?\" \/>\n<meta property=\"og:description\" content=\"In the world of cryptocurrency, Bitcoin is indisputably the leader in terms of security and decentralization. However, increasing user\" \/>\n<meta property=\"og:url\" content=\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/\" \/>\n<meta property=\"og:site_name\" content=\"Coin Engineer\" \/>\n<meta property=\"article:published_time\" content=\"2025-08-26T08:00:30+00:00\" \/>\n<meta property=\"article:modified_time\" content=\"2025-08-26T07:59:35+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/what-is-citrea.png\" \/>\n\t<meta property=\"og:image:width\" content=\"1280\" \/>\n\t<meta property=\"og:image:height\" content=\"720\" \/>\n\t<meta property=\"og:image:type\" content=\"image\/png\" \/>\n<meta name=\"author\" content=\"Haciyev Re\u015fit\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Haciyev Re\u015fit\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"11 minutes\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/\",\"url\":\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/\",\"name\":\"What is Citrea?\",\"isPartOf\":{\"@id\":\"https:\/\/coinengineer.net\/blog\/#website\"},\"primaryImageOfPage\":{\"@id\":\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#primaryimage\"},\"image\":{\"@id\":\"https:\/\/coinengineer.net\/blog\/what-is-citrea\/#primaryimage\"},\"thumbnailUrl\":\"https:\/\/coinengineer.net\/blog\/wp-content\/uploads\/2025\/08\/what-is-citrea.png\",\"datePublished\":\"2025-08-26T08:00:30+00:00\",\"dateModified\":\"2025-08-26T07:59:35+00:00\",\"author\":{\"@id\":\"https:\/\/coinengineer.net\/blog\/#\/schema\/person\/0a41a1cb75098be284f7e4059f16414d\"},\"description\":\"In the world of cryptocurrency, Bitcoin is indisputably the leader in terms of security and decentralization. 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