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Practical Byzantine Fault Tolerance (PBFT)

What is Practical Byzantine Fault Tolerance (PBFT)?

Practical Byzantine Fault Tolerance (PBFT) is a consensus algorithm designed to work efficiently in asynchronous systems while tolerating Byzantine faults. It's used in distributed computing systems, including some blockchain networks, to achieve consensus among nodes even when some nodes may be unreliable or malicious.

Key Characteristics

  1. Byzantine Fault Tolerant: Can handle arbitrary behavior from faulty nodes.

  2. High Performance: Offers high throughput and low latency in normal operation.

  3. Finality: Provides immediate finality once consensus is reached.

  4. Leader-Based: Utilizes a primary node (leader) to coordinate consensus.

  5. Asynchronous System Support: Functions in networks with unreliable timing.

How PBFT Works

  1. Request: A client sends a request to the primary node.

  2. Pre-Prepare: The primary broadcasts the request to backup nodes.

  3. Prepare: Nodes verify the request and broadcast prepare messages.

  4. Commit: Nodes broadcast commit messages after receiving enough prepares.

  5. Reply: Nodes execute the request and reply to the client.

Advantages of PBFT

  1. Efficiency: More efficient than Proof of Work in terms of energy and time.

  2. Immediate Finality: Transactions are final once consensus is reached.

  3. No Forking: Avoids the blockchain forking issues common in PoW systems.

  4. Scalability: Can handle higher transaction throughput than some other consensus mechanisms.

  5. Byzantine Fault Tolerance: Can function correctly even with malicious nodes.

Limitations and Challenges

  1. Node Limit: Efficiency decreases with a large number of nodes.

  2. Communication Overhead: Requires significant message exchange between nodes.

  3. Centralization Concerns: Reliance on a primary node can be seen as a form of centralization.

  4. Sybil Attack Vulnerability: Susceptible to Sybil attacks in permissionless networks.

  5. Complex Implementation: More complex to implement than some other consensus algorithms.

Similar Terms

  • Byzantine Fault Tolerance (BFT): The broader concept that PBFT implements practically.

  • Consensus Mechanism: The general category of mechanisms for achieving agreement in distributed systems.

  • Blockchain: Decentralized and immutable digital ledger technology that records transactions across a network of computers.

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For general questions, visit our Help Center or use the Intercom chat widget in the bottom right corner of any screen on this website. 


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© 2025 All Rights Reserved

ChainFi, Inc (dba "Arch Lending" and referred to as "Arch" on this website) is not a bank. 


Loan Services. Crypto backed loans (“Loans”) are offered to U.S. borrowers by ChainFi, Inc. NMLS #2637200. NMLS Consumer Access.


Loan Availability. Loan availability may vary based on jurisdiction. Loans are not available to U.S. residents of AL, CA, DE, HI, ID, IL, MN, MS, MT, NV, ND, RI, SC, SD, TX, VT, VA, or WA or to U.S. businesses in CA, DC, HI, MT, NV, NM, ND, RI, SD, or VT. We encourage you to contact us to determine if our loans are available in your state.


Loan Agreement. Loans are issued pursuant to a loan agreement between Arch and you. This legally binding document outlines your rights, obligations, interest rates, repayment schedules, potential fees, default consequences, and any other terms and conditions related to your loan. Your loan agreement may contain state-specific provisions. By signing the loan agreement, you acknowledge your acceptance of these terms, so please ensure you understand every aspect before proceeding. 


Interest Rates. Annual interest rates are subject to change and may vary based on loan type, the principal amount requested, and the borrower's jurisdiction of residence. 


Supported Assets. For the latest list of supported assets, refer to our Help Center.


No Financial, Investment or Tax Advice Provided. The information on this website, articles, guides, tools, or communications, is for general informational purposes only. It is not, and should not be construed as, financial, investment, tax, or other professional advice. Arch is not a financial advisor, investment advisor, broker, tax advisor, or accounting firm. We do not provide personalized advice or recommendations for your unique financial situation or goals. You should consult a qualified professional before making any financial, investment or tax decisions. Any examples, hypothetical scenarios, calculator results, or general discussions of financial or tax concepts are for illustration only and don't guarantee specific outcomes or apply to your personal circumstances. By using this website, you acknowledge you are solely responsible for your financial decisions and will seek independent professional advice as needed.


No Guarantee of Offers, Loans, or Returns. Your use or access to this website or platform does not guarantee the availability of any current and/or future offer, promotion, terms, loan, or return. All offers, promotions, terms, and loans are subject to availability and the sole discretion of Arch. We reserve the right to modify or withdraw any offering at any time without prior notice.


State-Specific Disclosures. Additional state-specific disclaimers may apply depending on your location. We encourage you to review all relevant disclaimers and terms carefully before proceeding.

State of Idaho Disclaimer. In Idaho, ChainFi, Inc is doing business as Arch Lending and does not conduct activity under the name Arch.

ChainFi, Inc (dba "Arch Lending"), 595 Broadway, Floor 4, New York, NY 10012


For general questions, visit our Help Center or use the Intercom chat widget in the bottom right corner of any screen on this website. 


For customer service or complaints, email us at support@archlending.com, or call us toll-free: +1 855-272-4670 between Monday-Friday from 9am-7pm ET and Saturday-Sunday from 10am-5pm ET.

© 2025 All Rights Reserved

ChainFi, Inc (dba "Arch Lending" and referred to as "Arch" on this website) is not a bank. 


Loan Services. Crypto backed loans (“Loans”) are offered to U.S. borrowers by ChainFi, Inc. NMLS #2637200. NMLS Consumer Access.


Loan Availability. Loan availability may vary based on jurisdiction. Loans are not available to U.S. residents of AL, CA, DE, HI, ID, IL, MN, MS, MT, NV, ND, RI, SC, SD, TX, VT, VA, or WA or to U.S. businesses in CA, DC, HI, MT, NV, NM, ND, RI, SD, or VT. We encourage you to contact us to determine if our loans are available in your state.


Loan Agreement. Loans are issued pursuant to a loan agreement between Arch and you. This legally binding document outlines your rights, obligations, interest rates, repayment schedules, potential fees, default consequences, and any other terms and conditions related to your loan. Your loan agreement may contain state-specific provisions. By signing the loan agreement, you acknowledge your acceptance of these terms, so please ensure you understand every aspect before proceeding. 


Interest Rates. Annual interest rates are subject to change and may vary based on loan type, the principal amount requested, and the borrower's jurisdiction of residence. 


Supported Assets. For the latest list of supported assets, refer to our Help Center.


No Financial, Investment or Tax Advice Provided. The information on this website, articles, guides, tools, or communications, is for general informational purposes only. It is not, and should not be construed as, financial, investment, tax, or other professional advice. Arch is not a financial advisor, investment advisor, broker, tax advisor, or accounting firm. We do not provide personalized advice or recommendations for your unique financial situation or goals. You should consult a qualified professional before making any financial, investment or tax decisions. Any examples, hypothetical scenarios, calculator results, or general discussions of financial or tax concepts are for illustration only and don't guarantee specific outcomes or apply to your personal circumstances. By using this website, you acknowledge you are solely responsible for your financial decisions and will seek independent professional advice as needed.


No Guarantee of Offers, Loans, or Returns. Your use or access to this website or platform does not guarantee the availability of any current and/or future offer, promotion, terms, loan, or return. All offers, promotions, terms, and loans are subject to availability and the sole discretion of Arch. We reserve the right to modify or withdraw any offering at any time without prior notice.


State-Specific Disclosures. Additional state-specific disclaimers may apply depending on your location. We encourage you to review all relevant disclaimers and terms carefully before proceeding.

State of Idaho Disclaimer. In Idaho, ChainFi, Inc is doing business as Arch Lending and does not conduct activity under the name Arch.

ChainFi, Inc (dba "Arch Lending"), 595 Broadway, Floor 4, New York, NY 10012


For general questions, visit our Help Center or use the Intercom chat widget in the bottom right corner of any screen on this website. 


For customer service or complaints, email us at support@archlending.com, or call us toll-free: +1 855-272-4670 between Monday-Friday from 9am-7pm ET and Saturday-Sunday from 10am-5pm ET.

© 2025 All Rights Reserved