824 research outputs found

    Reinforcing Security and Usability of Crypto-Wallet with Post-Quantum Cryptography and Zero-Knowledge Proof

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    Crypto-wallets or digital asset wallets are a crucial aspect of managing cryptocurrencies and other digital assets such as NFTs. However, these wallets are not immune to security threats, particularly from the growing risk of quantum computing. The use of traditional public-key cryptography systems in digital asset wallets makes them vulnerable to attacks from quantum computers, which may increase in the future. Moreover, current digital wallets require users to keep track of seed-phrases, which can be challenging and lead to additional security risks. To overcome these challenges, a new algorithm is proposed that uses post-quantum cryptography (PQC) and zero-knowledge proof (ZKP) to enhance the security of digital asset wallets. The research focuses on the use of the Lattice-based Threshold Secret Sharing Scheme (LTSSS), Kyber Algorithm for key generation and ZKP for wallet unlocking, providing a more secure and user-friendly alternative to seed-phrase, brain and multi-sig protocol wallets. This algorithm also includes several innovative security features such as recovery of wallets in case of downtime of the server, and the ability to rekey the private key associated with a specific username-password combination, offering improved security and usability. The incorporation of PQC and ZKP provides a robust and comprehensive framework for securing digital assets in the present and future. This research aims to address the security challenges faced by digital asset wallets and proposes practical solutions to ensure their safety in the era of quantum computing

    Cryptocurrencies Are Taxable and Not Free From Fraud

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    In this report, the authors discuss cryptocurrencies โ€” especially bitcoin โ€” and argue that because the IRS lists them as property, they are taxable, and because they are not as anonymous as once thought, they are not free from fraud. Cryptocurrencies are digital assets used as a medium of exchange, but they are not really coins. They can be sent electronically from one entity to another almost anywhere in the world with an internet connection. There are many cryptocurrencies in the market, including bitcoin, ethereum, ethereum classic, litecoin, nem, dash, iota, bitshares, monero, neo, and ripple. Many of the cryptocurrency networks are not controlled by a single entity or company; instead, a decentralized network of computers keeps track of the currency using a token ID. A ledger maintains a continuously growing list of date stamped transactions in real time called โ€œblocks.โ€ This technology is known as blockchain, which records, verifies, and stores transactions without a trusted central authority. The network instead relies on decentralized autonomous organizations (DAOs) with uncertain legal standing

    ๋ธ”๋ก์ฒด์ธ ๊ธฐ๋ฐ˜ ๋””์ง€ํ„ธ ์ž์‚ฐ์— ๋Œ€ํ•œ ๋ถ„์„ ์—ฐ๊ตฌ: ์ค‘์•™์€ํ–‰ ๋””์ง€ํ„ธ ํ™”ํ, ์Šคํ…Œ์ด๋ธ”์ฝ”์ธ, ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ์„ ์ค‘์‹ฌ์œผ๋กœ

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    ํ•™์œ„๋…ผ๋ฌธ(๋ฐ•์‚ฌ) -- ์„œ์šธ๋Œ€ํ•™๊ต๋Œ€ํ•™์› : ๊ณต๊ณผ๋Œ€ํ•™ ์‚ฐ์—…๊ณตํ•™๊ณผ, 2023. 2. ์ด์žฌ์šฑ.๋ณธ ๋…ผ๋ฌธ์€ ํƒˆ์ค‘์•™ํ™” ๊ธˆ์œต (DeFi) ์‹œ์žฅ์—์„œ ์œ ๋งํ•œ ์„ธ ๊ฐ€์ง€ ์ž์‚ฐ์ธ ์ค‘์•™์€ํ–‰ ๋””์ง€ํ„ธ ํ™”ํ, ์Šคํ…Œ์ด๋ธ” ์ฝ”์ธ ๋ฐ ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅํ•œ ํ† ํฐ์— ๋Œ€ํ•œ ์‹ฌ์ธต์ ์ธ ์‹ค์ฆ๋ถ„์„์„ ์ œ๊ณตํ•œ๋‹ค. ๋จผ์ € ํ˜„์žฌ ์ค‘์•™์€ํ–‰ ๋””์ง€ํ„ธ ํ™”ํ ์„ค๊ณ„์— ์žˆ์–ด์„œ ๊ฐ€์žฅ ํฐ ๊ฑธ๋ฆผ๋Œ์ด ๋˜๊ณ  ์žˆ๋Š” ๋‘ ๊ฐ€์ง€ ๋ฌธ์ œ๋ฅผ ํ•ด๊ฒฐํ•˜๊ธฐ ์œ„ํ•œ ๋ธ”๋ก์ฒด์ธ ๊ธฐ๋ฐ˜ ์ค‘์•™์€ํ–‰ ๋””์ง€ํ„ธ ํ™”ํ ๊ฒฐ์ œ ์‹œ์Šคํ…œ์„ ์ œ์•ˆํ•œ๋‹ค. ์ด ๋•Œ, ํฌ๋กœ์Šค-์ฒด์ธ ์•„ํ† ๋ฏน ์Šค์™‘ ๊ธฐ์ˆ ๊ณผ ๊ฒฉ์ž ๊ธฐ๋ฐ˜ ์ˆœ์ฐจ์  ํ†ตํ•ฉ ์„œ๋ช… (sequential aggregate signature) ๊ธฐ์ˆ ์ด ํ•จ๊ป˜ ํ™œ์šฉ๋œ๋‹ค. ๊ทธ๋ฆฌ๊ณ  ์Šคํ…Œ์ด๋ธ” ์ฝ”์ธ ์‹œ์žฅ์— ๋Œ€ํ•œ ์‹ฌ์ธต์  ์ดํ•ด๋ฅผ ์œ„ํ•ด ์ตœ๊ทผ์— ๋ฐœ์ƒํ•˜์˜€๋˜ ํ…Œ๋ผ-๋ฃจ๋‚˜ ์‚ฌํƒœ๋ฅผ ํŒŒ๊ธ‰ํšจ๊ณผ ์ง€์ˆ˜์™€ ํšจ๊ณผ์  ์ „์ด ์—”ํŠธ๋กœํ”ผ๋ฅผ ํ™œ์šฉํ•˜์—ฌ ๋ถ„์„ํ•˜์˜€๋‹ค. ์ด๋ฅผ ํ†ตํ•ด ์Šคํ…Œ์ด๋ธ”์ฝ”์ธ๊ณผ ์•”ํ˜ธํ™”ํ ์‹œ์žฅ ๊ฐ„์˜ ์—ฐ๊ฒฐ์„ฑ๊ณผ ์ •๋ณด ์ „์†ก์„ ์ •๋Ÿ‰ํ™”ํ•˜์˜€๋‹ค. ๊ทธ๋ฆฌ๊ณ  ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ์˜ ๊ฒฝ์šฐ, ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ์˜ ํŠน์„ฑ์ƒ ๊ธฐ์กด ์•”ํ˜ธํ™”ํ์— ๋น„ํ•ด ๊ฑฐ๋ž˜๋Ÿ‰์ด ์ ๋‹ค๋Š” ์ ์„ ์ฐฉ์•ˆํ•˜์—ฌ ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ์‹œ์žฅ ๋‚ด ์ˆ˜์ต๋ฅ ๊ณผ ๊ฑฐ๋ž˜๋Ÿ‰ ๊ฐ„์˜ ์ธ๊ณผ๊ด€๊ณ„๋ฅผ ๋ถ„์„ํ•œ๋‹ค. ์ค‘์•™์€ํ–‰ ๋””์ง€ํ„ธ ํ™”ํ์˜ ๊ฒฝ์šฐ, ํ˜„์žฌ ์ค‘์•™์€ํ–‰ ๋””์ง€ํ„ธ ํ™”ํ ์„ค๊ณ„์˜ ๋‘ ๊ฐ€์ง€ ๊ทผ๋ณธ์ ์ธ ๊ณผ์ œ๋ฅผ ํ•ด๊ฒฐํ•˜๋Š” ๋ธ”๋ก์ฒด์ธ ๊ธฐ๋ฐ˜ ๊ฒฐ์ œ ์‹œ์Šคํ…œ์„ ์ œ์•ˆํ•œ๋‹ค. ๋จผ์ € ๊ฐ์‚ฌ ๊ฐ€๋Šฅ์„ฑ์„ ์ œ๊ณตํ•˜๊ธฐ ์œ„ํ•ด ๊ฒฐ์ œ ์‹œ์Šคํ…œ์— ๊ด€๋ฆฌ์ž ์›์žฅ์„ ๋„์ž…ํ•˜๊ณ , ๊ด€๋ฆฌ์ž ๋…ธ๋“œ๊ฐ€ ๋ชจ๋“  ๊ฑฐ๋ž˜์— ์ฐธ์—ฌํ•  ์ˆ˜ ์žˆ๋„๋ก ํ•˜์˜€๋‹ค. ๋ณธ ๋ชจ๋ธ์€ ํฌ๋กœ์Šค ์ฒด์ธ ์•„ํ† ๋ฏน ์Šค์™‘๊ณผ ๊ฒฉ์ž ๊ธฐ๋ฐ˜ ์ˆœ์ฐจ์  ํ†ตํ•ฉ์„œ๋ช…์„ ํ™œ์šฉํ•˜์—ฌ ์•ˆ์ „์„ฑ์„ ๋ณด์žฅํ•˜๊ณ  ๊ตญ๊ฐ€๊ฐ„ ๊ฒฐ์ œ๋ฅผ ๊ฐ€๋Šฅ์ผ€ํ•œ๋‹ค. ๋˜ํ•œ ์ œ์•ˆ ๋ชจ๋ธ์€ ๊ฑฐ๋ž˜ ๊ธฐ๋ก์„ ์ถ”์ ํ•˜๊ณ  ๊ฑฐ๋ž˜ ๊ธฐ๋ก๊ณผ ๊ฑฐ๋ž˜ ์ฐธ๊ฐ€์ž์˜ ์‹ ์›์„ ์ผ์น˜์‹œํ‚ฌ ์ˆ˜ ์žˆ์œผ๋ฉฐ, ๊ฒฉ์ž ๊ธฐ๋ฐ˜ ์•”ํ˜ธ ํ™œ์šฉ์„ ํ†ตํ•ด ๋ฏธ๋ž˜์˜ ์–‘์ž ์ปดํ“จํ„ฐ ๊ณต๊ฒฉ์—๋„ ๊ฐ•๊ฑดํ•  ์ˆ˜ ์žˆ๋‹ค. ๋™์ผ ํ”„๋กœํ† ์ฝœ ๋‚ด์˜ ํ† ํฐ์„ ์ค€๋น„๊ธˆ์œผ๋กœ ๊ฐ–๋Š” ์Šคํ…Œ์ด๋ธ” ์ฝ”์ธ์˜ ๊ฒฝ์šฐ, ํ•ด๋‹น ํ”„๋กœํ† ์ฝœ์— ๋Œ€ํ•œ ๋Œ€์ค‘์˜ ์‹ ๋ขฐ๊ฐ€ ๋ฌด๋„ˆ์ง„๋‹ค๋ฉด ๋ฐ์Šค ์ŠคํŒŒ์ด๋Ÿด์— ๋น ์งˆ ์œ„ํ—˜์ด ๋งค์šฐ ๋†’๋‹ค. ์ •์ƒ์ ์ธ ์‹œ์žฅ ์ƒํ™ฉ์—์„œ๋Š” ์Šคํ…Œ์ด๋ธ”์ฝ”์ธ์˜ ๊ฐ€๊ฒฉ์ด ๋งค์šฐ ์•ˆ์ •์ ์ด๊ธฐ ๋•Œ๋ฌธ์—, ์ด์— ๋Œ€ํ•œ ๋ถ„์„์„ ์ง„ํ–‰ํ•˜๋Š” ๋ฐ์— ์–ด๋ ค์›€์ด ์žˆ๋‹ค. ๋”ฐ๋ผ์„œ, ์Šคํ…Œ์ด๋ธ”์ฝ”์ธ์˜ ์‹œ์žฅ ์˜ํ–ฅ๋ ฅ์„ ์ •๋Ÿ‰ํ™”ํ•˜๊ธฐ ์œ„ํ•˜์—ฌ, ์Šคํ…Œ์ด๋ธ”์ฝ”์ธ์˜ ๊ฐ€๊ฒฉ ๋ณ€๋™์„ฑ์ด ๋งค์šฐ ์‹ฌํ–ˆ๋˜ ์ตœ๊ทผ์˜ ํ…Œ๋ผ-๋ฃจ๋‚˜ ํญ๋ฝ ์‚ฌํƒœ๋ฅผ ๋ถ„์„ํ•˜์˜€์œผ๋ฉฐ ์ด ๋•Œ, ํŒŒ๊ธ‰ํšจ๊ณผ ์ง€์ˆ˜์™€ ํšจ๊ณผ์  ์ „์ด ์—”ํŠธ๋กœํ”ผ์™€ ๊ฐ™์€ ๊ณ„๋Ÿ‰ ๊ฒฝ์ œํ•™์  ๋ฐฉ๋ฒ•๋ก ์„ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ๋ถ„์„์—๋Š” 1์‹œ๊ฐ„ ๋ฐ 5๋ถ„ ๋‹จ์œ„ ์•”ํ˜ธํ™”ํ ๊ฐ€๊ฒฉ, ๊ตฌ๊ธ€ ํŠธ๋ Œ๋“œ ์ง€์ˆ˜, ๊ทธ๋ฆฌ๊ณ  StockTwits์— ํฌ์ŠคํŒ…๋œ ํŠธ์œ—๋“ค์„ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ์‹คํ—˜ ๊ฒฐ๊ณผ, ๋””ํŽ˜๊ทธ๊ฐ€ ์‹œ์ž‘๋˜๋ฉด์„œ ์Šคํ…Œ์ด๋ธ” ์ฝ”์ธ์˜ ํŒŒ๊ธ‰ํšจ๊ณผ๊ฐ€ ๊ธ‰๊ฒฉํ•˜๊ฒŒ ์ฆ๊ฐ€ํ–ˆ๊ณ , ๋ฃจ๋‚˜ ์ฝ”์ธ์ด ์ „์ฒด ์•”ํ˜ธํ™”ํ ์‹œ์žฅ์—์„œ ํฐ ์˜ํ–ฅ๋ ฅ์„ ๊ฐ€์กŒ์Œ์„ ํ™•์ธํ•˜์˜€๋‹ค. ๋˜ํ•œ ๋ฃจ๋‚˜์—์„œ ๋น„ํŠธ์ฝ”์ธ์ด๋‚˜ ์ด๋”๋ฆฌ์›€๊ณผ ๊ฐ™์€ ๋‹ค๋ฅธ ์ฃผ์š” ์•”ํ˜ธํ™”ํ๋กœ์˜ ํšจ๊ณผ์  ์ „์ด ์—”ํŠธ๋กœํ”ผ๋„ ํ•จ๊ป˜ ์ฆ๊ฐ€ํ•˜์˜€๋‹ค. ๊ทธ๋Ÿฌ๋‚˜ ํˆฌ์ž์ž ๊ฐ์„ฑ์˜ ๊ฒฝ์šฐ ๋ฃจ๋‚˜๋กœ์˜ ์ „์ด ์—”ํŠธ๋กœํ”ผ๊ฐ€ ํฌ๊ฒŒ ๊ฐ์†Œํ•จ์— ๋”ฐ๋ผ, ํญ๋ฝ ์‚ฌํƒœ ๋™์•ˆ ์ •๋ณด ์†ก์‹ ์ž๋กœ์„œ์˜ ์—ญํ• ์„ ์žƒ์–ด๋ฒ„๋ ธ๋‹ค. ์ด๋Ÿฌํ•œ ํ˜„์ƒ์ด ์ผ์–ด๋‚œ ์ด์œ ๋Š”, ๋ฃจ๋‚˜์˜ ๋ฏธ๋ž˜์— ๋Œ€ํ•œ ํˆฌ์ž์ž๋“ค์˜ ์˜๊ฒฌ์ด ๋งค์šฐ ๋ถ„๋ถ„ํ•˜์—ฌ ์‹œ์žฅ ๋‚ด ํˆฌ์ž์ž ๊ฐ์„ฑ์ด ๋ฐฉํ–ฅ์„ฑ์„ ์žƒ์—ˆ๊ธฐ ๋•Œ๋ฌธ์ด๋ผ๊ณ  ํ•ด์„ํ•  ์ˆ˜ ์žˆ๋‹ค. ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ ์‹œ์žฅ์€, ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ์ด ๊ฐ–๋Š” ๊ณ ์œ ์„ฑ์ด๋ผ๋Š” ํŠน์„ฑ์œผ๋กœ ์ธํ•ด ๊ธฐ์กด ์•”ํ˜ธํ™”ํ ์‹œ์žฅ๊ณผ๋Š” ์ฐจ์ด์ ์ด ์žˆ๋‹ค. ์ด์— ๋”ฐ๋ผ ๊ฑฐ๋ž˜์˜ ์œ ๋™์„ฑ์ด ๋งค์šฐ ๋‚ฎ์•„์ง€๊ฒŒ ๋œ๋‹ค. ๋‹ค์‹œ ๋งํ•ด, ๊ฐœ๋ณ„ ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ์— ๋Œ€ํ•œ ์ ํ•ฉํ•œ ๋งค๋„์ž์™€ ๋งค์ˆ˜์ž๋ฅผ ์ฐพ๋Š” ์ž‘์—…์ด ๋น„๊ต์  ์˜ค๋ž˜ ๊ฑธ๋ฆด ์ˆ˜ ์žˆ๋‹ค. ์ด๋Ÿฌํ•œ ํŠน์„ฑ์„ ์•Œ์•„๋ณด๊ธฐ ์œ„ํ•˜์—ฌ ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ์˜ ๊ฑฐ๋ž˜๋Ÿ‰๊ณผ ๊ฐ€๊ฒฉ ๊ฐ„์˜ ์ธ๊ณผ๊ด€๊ณ„๋ฅผ ์•Œ์•„๋ณด๊ณ ์ž ํ•˜์˜€๋‹ค. ์ด ๋•Œ, ๋ถ„์œ„์ˆ˜๋ณ„ ๊ทธ๋ ˆ์ธ์ € ์ธ๊ณผ๊ด€๊ณ„ ๊ฒ€์ •์„ ์‚ฌ์šฉํ•˜์˜€๋‹ค. ๋ฐ์ดํ„ฐ์˜ ๊ฒฝ์šฐ, ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ์˜ ์ผ์ผ ๊ฑฐ๋ž˜๋Ÿ‰๊ณผ ๊ฐ€๊ฒฉ์„ ์‚ฌ์šฉํ•˜์˜€์œผ๋ฉฐ, ๋ถ„์„ ๊ฒฐ๊ณผ ์ „๋ฐ˜์ ์ธ ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ ์‹œ์žฅ์— ๋Œ€ํ•ด์„œ๋Š” ๊ทน๋‹จ์ ์ธ ์‹œ์žฅ ์ƒํ™ฉ ์†์—์„œ ์ธ๊ณผ ๊ด€๊ณ„๊ฐ€ ๋”์šฑ ๊ฐ•ํ•˜๊ฒŒ ๋‚˜ํƒ€๋‚จ์„ ๋ณด์˜€๋‹ค. ํ•˜์ง€๋งŒ ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ ํ”„๋กœ์ ํŠธ ๋ณ„๋กœ ๋ถ„์„ํ•œ ๊ฒฐ๊ณผ๋Š” ์ด์™€ ๋‹ค๋ฅด๊ฒŒ ๋‚˜ํƒ€๋‚ฌ๋‹ค. ์˜ˆ๋ฅผ ๋“ค์–ด, ์•ก์‹œ ์ธํ”ผ๋‹ˆํ‹ฐ๋Š” ๋ชจ๋“  ๋ถ„์œ„์ˆ˜์—์„œ ๊ฑฐ๋ž˜๋Ÿ‰๊ณผ ์ˆ˜์ต๋ฅ ์ด ๊ฐ•ํ•œ ์ธ๊ณผ๊ด€๊ณ„๋ฅผ ๊ฐ€์ง„ ๋ฐ”๋ฉด, ๋””์„ผํŠธ๋Ÿด๋žœ๋“œ๋Š” ์ค‘์•™๊ฐ’ ์ฃผ๋ณ€์—์„œ๋งŒ ์ธ๊ณผ๊ด€๊ณ„๋ฅผ ๋ณด์˜€๋‹ค. ๋˜ํ•œ ์ƒŒ๋“œ๋ฐ•์Šค์˜ ๊ฑฐ๋ž˜๋Ÿ‰์€ ์˜คํžˆ๋ ค ์•ฝ์„ธ์žฅ ์†์—์„œ ์ƒŒ๋“œ๋ฐ•์Šค ๊ฐ€๊ฒฉ์„ ์˜ˆ์ธกํ•˜๋Š” ๋ฐ์—๋งŒ ๋„์›€์„ ์ค„ ์ˆ˜ ์žˆ์Œ์„ ํ™•์ธํ•˜์˜€๋‹ค. ๋งˆ์ง€๋ง‰์œผ๋กœ, ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ๊ณผ ํ•ด๋‹น ํ† ํฐ์ด ์กด์žฌํ•˜๋Š” ํ”„๋กœํ† ์ฝœ ๋‚ด ๊ธฐ๋ณธ ์•”ํ˜ธํ™”ํ์™€์˜ ์ธ๊ณผ๊ด€๊ณ„๋ฅผ ๋ถ„์„ํ•˜์˜€๋‹ค. ์‹ค์ฆ ์‹คํ—˜ ๊ฒฐ๊ณผ, ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ์˜ ๊ฐ€๊ฒฉ๊ณผ ํ”„๋กœํ† ์ฝœ ๋‚ด ๊ธฐ๋ณธ ์•”ํ˜ธํ™”ํ์˜ ๊ฐ€๊ฒฉ์—๋Š” ๋ฐ€์ ‘ํ•œ ๊ด€๊ณ„๊ฐ€ ์žˆ์œผ๋ฉฐ, ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ ๊ฑฐ๋ž˜ ๋ฐ ํˆฌ์ž ์‹œ์—๋„ ์ด๋Ÿฌํ•œ ์ ์„ ๊ณ ๋ คํ•ด์•ผํ•จ์„ ๋ณด์˜€๋‹ค. ๋ณธ ๋…ผ๋ฌธ์€ ๋ธ”๋ก์ฒด์ธ ๊ธฐ๋ฐ˜ ์ค‘์•™์€ํ–‰ ๋””์ง€ํ„ธ ํ™”ํ, ์Šคํ…Œ์ด๋ธ”์ฝ”์ธ ๋ฐ ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ๊ณผ ๊ฐ™์€ ๋‹ค์–‘ํ•œ ์œ ํ˜•์˜ ๋””์ง€ํ„ธ ์ž์‚ฐ์— ๋Œ€ํ•œ ์‹ค์ฆ๋ถ„์„์„ ์ง„ํ–‰ํ•˜์˜€๋‹ค. ๊ฐ€์žฅ ๋จผ์ €, ์ „ํ†ต ๊ธˆ์œต์‹œ์žฅ๊ณผ ํƒˆ์ค‘์•™ํ™” ๊ธˆ์œต์‹œ์žฅ์˜ ํ˜„ ๊ธฐ์ˆ ์  ์žฅ์• ๋ฌผ์„ ํ•ด๊ฒฐํ•˜๊ธฐ ์œ„ํ•œ ๋ธ”๋ก์ฒด์ธ ๊ธฐ๋ฐ˜ ์ค‘์•™์€ํ–‰ ๋””์ง€ํ„ธ ํ™”ํ๋ฅผ ์ œ์•ˆํ•˜์˜€๋‹ค. ๋˜ํ•œ ์Šคํ…Œ์ด๋ธ” ์ฝ”์ธ์˜ ๋ฐ์Šค ์ŠคํŒŒ์ด๋ฅผ์— ๋Œ€ํ•œ ๊ณ„๋Ÿ‰๊ฒฝ์ œํ•™์  ๋ถ„์„์„ ํ†ตํ•˜์—ฌ ์Šคํ…Œ์ด๋ธ”์ฝ”์ธ์ด ์•”ํ˜ธํ™”ํ ๋ฐ ํƒˆ์ค‘์•™ํ™” ๊ธˆ์œต์‹œ์žฅ์— ์ง€๋Œ€ํ•œ ์˜ํ–ฅ์„ ๋ฏธ์น˜๊ณ  ์žˆ์Œ์„ ๋ณด์˜€๋‹ค. ๋˜ํ•œ, ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ ์‹œ์žฅ์˜ ์ˆ˜์ต๋ฅ -๊ฑฐ๋ž˜๋Ÿ‰ ์ธ๊ณผ๊ด€๊ณ„๋ฅผ ํ™•์ธํ•˜์˜€์œผ๋ฉฐ, ์ด๋ฅผ ํ†ตํ•ด ๋‹ค์–‘ํ•œ ์‹œ์žฅ ์ƒํ™ฉ์— ๋†“์—ฌ ์žˆ๋Š” ๋Œ€์ฒด ๋ถˆ๊ฐ€๋Šฅ ํ† ํฐ ํˆฌ์ž์ž๋“ค์—๊ฒŒ ๋„์›€์„ ์ค„ ์ˆ˜ ์žˆ์„ ๊ฒƒ์œผ๋กœ ๊ธฐ๋Œ€ํ•œ๋‹ค.This dissertation provides an in-depth analysis of three promising assets in the DeFi market: CBDCs, stablecoins, and NFTs. For CBDCs, a blockchain-based CBDC settlement model is proposed using cross-chain atomic swaps and lattice-based sequential aggregate signature scheme to address two challenging issues. For stablecoins, the connectedness and information transmission between the stablecoin and cryptocurrency market is quantified to conclude that CBDCs can mitigate financial risks. For NFTs, the return-volume causal relationships in the NFT markets are analyzed due to the low transaction volume. For CBDCs, we propose a blockchain-based CBDC settlement model which addresses two fundamental challenges in CBDC design. It introduces an administrator ledger to the settlement system to provide auditability and allows the administrator node to participate in every transaction. The model also uses cross-chain atomic swap technology and a lattice-based sequential aggregate signature scheme to ensure safety and enable cross-border payments. These features make the model suitable for the growing needs for stable and reliable digital currencies. Our model provides a secure and reliable way to track transaction records and match the identity of transaction participants, while also protecting against malicious behavior and quantum computer attacks. Stablecoins backed with their own protocol's native tokens are highly susceptible to death spirals if the corresponding blockchain protocol is met with public distrust. During normal market conditions, the impact of stablecoins on the cryptocurrency market is difficult to measure as their prices remain fairly stable. To quantify the impact of the stablecoin, we analyze the recent Terra-Luna crash with econometric methodologies such as the spillover index and effective transfer entropy. Hourly and 5-minute cryptocurrency prices, Google Trends index and tweets posted on StockTwits were collected and used to measure the spillover effect. Results showed that the spillover effect of the stablecoin increased rapidly as the depeg started, and LUNA gained influence in the overall cryptocurrency market. The effective transfer entropy from LUNA to other cryptocurrencies such as BTC and ETH also increased dramatically. However, investor sentiment lost its role as an information transmitter during the crash, as the effective transfer entropy from the investor sentiment to LUNA decreased significantly. We conclude that the collusion between bearish and bullish opinions about the future of LUNA led to the market sentiment losing its influence. NFT markets are distinct from traditional cryptocurrency markets due to their uniqueness. This makes it difficult to find the right buyer and seller pair for each individual NFT. To understand the relationship between trading volume of NFTs and their prices, we used the Granger causality test in quantiles. Our data included daily transaction volume and price of NFTs. The results showed that the causality from overall NFT volume to return became stronger in extreme market conditions. However, different NFT projects had different behaviors. For example, Axie Infinity had strong causality in every quantile, while Decentraland only had a causal relationship around the median. Additionally, the transaction volume of The Sandbox was only helpful in forecasting The Sandbox prices during bearish markets conditions. Lastly, we found a strong causal relationship between NFT returns and the return of its in-protocol native cryptocurrencies. Overall, our analysis showed that NFT volume and prices are closely related and should be taken into account when trading NFTs. This dissertation has explored the various types of digital assets, such as blockchain-based CBDCs, stablecoins, and NFTs. It has proposed a blockchain-based CBDC model to address the current obstacles in traditional and decentralized financial markets. The econometric analysis of stablecoin death spiral has revealed the significant impact of stablecoin on the cryptocurrency and DeFi markets. Additionally, the return-volume causal relationships in the NFT markets have been confirmed, providing guidance to NFT investors in different market conditions.Chapter 1 Introduction 1 1.1 Motivation of the Dissertation 1 1.2 Aims of the Dissertation 8 1.3 Organization of the Disseration 11 Chapter 2 Analysis on Blockchain-based CBDC Settlement System 12 2.1 Chapter Overview 12 2.2 Defining our CBDC research goal 16 2.2.1 Security and Privacy issues in CBDCs 16 2.2.2 Our Research Challenges in CBDC 31 2.3 Preliminaries 35 2.3.1 CBDC: State of Adoption 35 2.3.2 Cryptographic Background 36 2.4 Proposed Model 39 2.4.1 Model Description 39 2.4.2 Model Architecture 43 2.4.3 Our signature scheme: AggSign 45 2.5 Security Analysis 48 2.5.1 Security of the Settlement System 48 2.5.2 Security of AggSign 51 2.6 Proof-of-Concept Experiments and Analysis 60 2.6.1 Simulation Setting 60 2.6.2 Experimental Results 62 2.7 Chapter Summary 65 Chapter 3 Quantifying the Connectedness between the Algorithmic based Stablecoin and Cryptocurrency: The Impact of Death Spiral 67 3.1 Chapter Overview 67 3.2 Data and Methodology 71 3.2.1 Data 71 3.2.2 Methodology 73 3.3 Empirical Findings 75 3.3.1 Return and volatility spillover effects 75 3.3.2 Effective Transfer Entropy 84 3.4 Chapter Summary 88 Chapter 4 Return-Volume Relationship in Non-Fungible Tokens:Evidence from the Granger Causality in Quantiles 92 4.1 Chapter Overview 92 4.2 Data and Methodology 95 4.2.1 Data 95 4.2.2 Methodology: Granger causality test in quantiles 98 4.3 Empirical results 101 4.3.1 Causal effects of NFT volume on return 101 4.3.2 Causal effects of NFT return on volume 105 4.3.3 Causal effects between NFTs and their native cryptocurrencies 108 4.4 Chapter Summary 111 Chapter 5 Conclusion 113 5.1 Contributions of the Dissertation 113 5.2 Future Works 117 Bibliography 118 ๊ตญ๋ฌธ์ดˆ๋ก 141๋ฐ•

    Demystifying Quantum Blockchain for Healthcare

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    The application of blockchain technology can be beneficial in the field of healthcare as well as in the fight against the COVID-19 epidemic. In this work, the importance of blockchain is analyzed and it is observed that blockchain technology and the processes associated with it will be utilised in the healthcare systems of the future for data acquisition from sensors, automatic patient monitoring, and secure data storage. This technology substantially simplifies the process of carrying out operations because it can store a substantial quantity of data in a dispersed and secure manner, as well as enable access whenever and wherever it is required to do so. With the assistance of quantum blockchain, the benefits of quantum computing, such as the capability to acquire thermal imaging based on quantum computing and the speed with which patients may be located and monitored, can all be exploited to their full potential. Quantum blockchain is another tool that can be utilised to maintain the confidentiality, authenticity, and accessibility of data records. The processing of medical records could potentially benefit from greater speed and privacy if it combines quantum computing and blockchain technology. The authors of this paper investigate the possible benefits and applications of blockchain and quantum technologies in the field of medicine, pharmacy and healthcare systems. In this context, this work explored and compared quantum technologies and blockchain-based technologies in conjunction with other cutting-edge information and communications technologies such as ratification intelligence, machine learning, drones, and so on

    Blockchain Securities Issues: Decentralized Identity System With Key Management Perspective

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    Blockchain was created many years ago to solve the problems of data transfer Integrity, several years later the issues persist. Blockchain securities are one of the most important considerations to be investigated, and data integrity is about ensuring the accuracy and validity of messages such that when they are read, they are the same as when they were first written. It is of the opinion that passing information across from one person to another cannot be the same as it was first said at the onset. Our work investigated Blockchain security issues, studying Integrity emanating from transactions across the blocks and how to deal with the securities issues. It also investigated decentralization and issues in blockchain to investigate how to mitigate the security issues associated with blockchain. It further discusses the use of key management in solving security issues in blockchain, viewing different key management systems of private and public keys, and solutions in addressing the blockchain problems. Lastly, we contributed the use of Decentralized Identity systems (DIDs) into the blockchain where we use a unique identifier, โ€œID.meโ€ to verifier the individual credentials before any transaction, this was done by sending a digital ID through the issuer to the verifier to authenticate the integrity and identity of the holder and this proof worthy of protecting the information and maintaining the privacy of the user of the blockchain technology

    SoK: Cryptocurrency Wallets -- A Security Review and Classification based on Authentication Factors

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    In this work, we review existing cryptocurrency wallet solutions with regard to authentication methods and factors from the user's point of view. In particular, we distinguish between authentication factors that are verified against the blockchain and the ones verified locally (or against a centralized party). With this in mind, we define notions for kโˆ’factork-factor authentication against the blockchain and kโˆ’factork-factor authentication against the authentication factors. Based on these notions, we propose a classification of authentication schemes. We extend our classification to accommodate the threshold signatures and signing transactions by centralized parties (such as exchanges or co-signing services). Finally, we apply our classification to existing wallet solutions, which we compare based on various security and key-management features.Comment: arXiv admin note: text overlap with arXiv:1812.0359

    Foundations, Properties, and Security Applications of Puzzles: A Survey

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    Cryptographic algorithms have been used not only to create robust ciphertexts but also to generate cryptograms that, contrary to the classic goal of cryptography, are meant to be broken. These cryptograms, generally called puzzles, require the use of a certain amount of resources to be solved, hence introducing a cost that is often regarded as a time delay---though it could involve other metrics as well, such as bandwidth. These powerful features have made puzzles the core of many security protocols, acquiring increasing importance in the IT security landscape. The concept of a puzzle has subsequently been extended to other types of schemes that do not use cryptographic functions, such as CAPTCHAs, which are used to discriminate humans from machines. Overall, puzzles have experienced a renewed interest with the advent of Bitcoin, which uses a CPU-intensive puzzle as proof of work. In this paper, we provide a comprehensive study of the most important puzzle construction schemes available in the literature, categorizing them according to several attributes, such as resource type, verification type, and applications. We have redefined the term puzzle by collecting and integrating the scattered notions used in different works, to cover all the existing applications. Moreover, we provide an overview of the possible applications, identifying key requirements and different design approaches. Finally, we highlight the features and limitations of each approach, providing a useful guide for the future development of new puzzle schemes.Comment: This article has been accepted for publication in ACM Computing Survey

    A survey paper on blockchain and its implementation to reduce security risks in various domains

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    Every technology with its powerful uses has issues connected to it and security is at the top of it. As for the changing environment, the world has been shifting to Virtual Reality, the new coming world seems to be the internet and blockchain technology which is more powerful than others and has its applications in every field, be it quantum computing, internet of things, security or others. This survey paper covers the blockchain and its security in different fields of sciences and technology. We begin with the introduction of blockchain and then discuss its structure. After that security issues have been highlighted which include attacks and their behavior in quantum computing, internet of things, cloud computing. Furthermore, we have discussed the most common types of attacks and the SRM model of blockchain followed by the conclusion
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