Pi 幣是什麼？數位貨幣「π」到底是韭菜傳說，還是改寫歷史的神話！？

從 2020 年 3 月開始，全球開始發起關於「Pi Coin」的熱潮，當在實際找尋資料時發現，支持與反對的聲音勢不兩立。而這讓幣圈玩家炸了鍋討論的「π」到底是什麼？

手機挖礦
#

如果你只是想知道如何用手機賺 Pi Coin，那麼可以直接看我的下一篇文章。
#

Pi 幣？
#

「π 幣」是一種「數位貨幣」，又稱「Pi 幣」、「派幣」、「Pi Coin」甚至被稱作是「下一個比特幣」。其主要核心技術為「Pi Network」。(Pi Network 官方：https://minepi.com/)

Pi Network 起源
#

「Pi Network」該項目於 2019/03/14 啟用，由「Leland Stanford Junior University (小利蘭·史丹佛大學，又稱 斯坦福大學)」的 3 名學生所共同開發，分別是：

Dr. Nicolas Kokkalis, Head of Technologies;
Dr. Chengdiao Fan, Head of Product;
Vincent McPhillip, Head of Community.

資料來源：https://minepi.com/team

Pi Coin 值多少錢？
#

當前 Pi Network 還處於測試階段，因此若要談價值… 可以說是個問號，必須等到正式上線之後才會知道，這也正是許多人所質疑該數位貨幣是否能在未來順利發展的點。

如何獲取 Pi Coin？
#

以下是轉自 Pi Network White-Paper(Pi Network 白皮書)：

There are four roles Pi users can play, as Pi miners. Namely:
Pioneer
A user of the Pi mobile app who is simply confirming that they are not a “robot” on a daily basis. This user validates their presence every time they sign in to the app. They can also open the app to request transactions (e.g. make a payment in Pi to another Pioneer)
Contributor
A user of the Pi mobile app who is contributing by providing a list of pioneers he or she knows and trusts. In aggregate, Pi contributors will build a global trust graph.
Ambassador
A user of the Pi mobile app who is introducing other users into Pi network.
Node
A user who is a pioneer, a contributor using the Pi mobile app, and is also running the Pi node software on their desktop or laptop computer. The Pi node software is the software that runs the core SCP algorithm, taking into account the trust graph information provided by the Contributors.

大致上意思是：

用戶們可以透過扮演以下 4 種身份來取得 Pi Coin：
Pioneer (先鋒)
Pi Network 提供手機 APP，用戶只需每天使用手機上線點擊，讓他們確認你不是「機器人」，即可開始「挖礦 (Mining)」。(以 Faucet (水龍頭) 的方式進行)
Contributor (貢獻者)
Pi APP 的用戶通過提供他或她認識和信任的先驅者列表來做出貢獻。
Ambassador (大使)
Pi移動應用程序的用戶，正在將其他用戶引入Pi網絡。
Node (節點)
先鋒用戶，使用Pi移動應用程序的用戶，並且還在其台式機或便攜式計算機上運行Pi節點軟件。Pi節點軟件是運行核心SCP算法的軟件，同時考慮了貢獻者提供的信任圖信息。

Pi Network 項目流程
#

Phase 1 - Design, Distribution, Trust Graph Bootstrap. (設計、分發、信任圖引導程序)
Pi 伺服器開始模擬去中心化的運作模式，並以 Faucet (水龍頭) 的方式運行 (即前面所說：Pioneer 每天透過 APP 點擊，確認自己不是機器人即可以 Faucet (水龍頭) 的方式挖礦獲取 Pi Coin)，並且開始少量測試 KYC (實名認證)。
與第三階段「Mainnet (主網)」相比，該階段更容易改善用戶體驗。此階段於 2019/03/14 開始運作，並持續一年的時間，於 2020/03 末進入第二階段「Testnet (測試網)」。
Phase 2 - Testnet (測試網)
該階段將會與第三階段「Mainnet (主網)」使用相同的精確信任圖，但其中使用的是 Pi 測試幣，另外，也將開始大量測試 KYC (實名認證)。
官方也於該階段發布了 Node (節點) 程式，並且鼓勵用戶們啟動節點。此外，第二階段將與第一階段並行運作，並且定期比較兩個系統的結果，若結果始終相同，那麼就代表準備就緒，即可開始迎向第三階段「Mainnet (主網)」。
Phase 3 - Mainnet (主網)
此階段為主網路正式運行，不僅會關閉前兩項階段，並且每個使用者必須接受 KYC (實名認證)，因為 Pi Network 只允許一人擁有一個帳戶，假的帳戶及重複的帳戶餘額將被丟棄。
並且在這個階段，正式開始開放交易 Pi Coin，也正是如此，Pi Coin 於該階段，也開始有了實際的價值。未來的更新將會由 Pi Network 開發人員社區 以及 Pi Network 核心團隊 共同提供，並由委員會提出更新。

詳情請查閱 Pi Network White-Paper(Pi Network 白皮書) 原文：

Roadmap / Deployment plan
Phase 1 - Design, Distribution, Trust Graph Bootstrap.
The Pi server is operating as a faucet emulating the behavior of the decentralized system as it will function once its live. During this phase improvements in the user experience and behavior are possible and relatively easy to make compared to the stable phase of the main net. All minting of coins to users will be migrated to the live net once it launches. In other words, the livenet will pre-mint in its genesis block all account holder balances generated during Phase 1, and continue operating just like the current system but fully decentralized. Pi is not listed on exchanges during this phase and it is impossible to “buy” Pi with any other currency.
Phase 2 - Testnet
Before we launch the main net, the Node software will be deployed on a test net. The test net will use the same exact trust graph as the main net but on a testing Pi coin. Pi core team will host several nodes on the test net, but will encourage more Pioneers to start their own nodes on the testnet. In fact, in order for any node to join the main net, they are advised to begin on the testnet. The test net will be run in parallel to the Pi emulator in phase one, and periodically, e.g. daily, the results from both systems will be compared to catch the gaps and misses of the test net, which will allow Pi developers to propose and implement fixes. After a thorough concurrent run of both systems, testnet will reach a state where its results consistently match the emulator’s. At that time when the community feels its ready, Pi will migrate to the next phase.
Phase 3 - Mainnet
When the community feels the software is ready for production, and it has been thoroughly tested on the testnet, the official mainnet of the Pi network will be launched. An important detail is that, in the transition into the mainnet, only accounts validated to belong to distinct real individuals will be honored. After this point, the faucet and Pi network emulator of Phase 1 will be shut down and the system will continue on its own forever. Future updates to the protocol will be contributed by the Pi developer community and Pi’s core team, and will be proposed by the committee. Their implementation and deployment will depend on nodes updating the mining software just like any other blockchains. No central authority will be controlling the currency and it will be fully decentralized. Balances of fake users or duplicate users will be discarded. This is the phase when Pi can be connected to exchanges and be exchanged for other currencies.

Pi Coin 的供給
#

Pi Coin 的經濟模型為「Balancing Scarcity and Access (平衡稀缺性和獲取)」。

優點
固定供給
以 Bitcoin (比特幣) 為例 (以下統稱 BTC)，BTC 在被設計出來的時候，其產量上限就是固定的，上限為「2,100 萬」顆 BTC。全世界只有 2,100 萬顆的 BTC 在 75 億的人口中流通，這樣的稀缺性也正是導致 BTC 價值高的重點因素之一。
減少區塊獎勵 (礦工獎勵)
BTC 的這種分配方案更是增強了稀缺性。BTC 的挖礦獎勵每 210,000 個區塊將會減半 (約每 4 年一次)。
早期，BTC 挖礦獎勵為 50 BTC，最近則為 12.5 BTC，並在 2020 年 05 月減半為 6.25 BTC。
缺點
反向傳播模型意味著 不均勻
BTC 所採用的是 Backpropagation (反向傳播) 模型 (一開始少數的人賺著多數的 BTC，如今多數的人賺著少數的 BTC )。因此導致 BTC 分配不均。
囤積阻礙了作為交易媒介的使用
儘管 BTC 被發佈為「點對點電子現金」系統，但 BTC 的相對稀缺性阻礙了 BTC 作為交易媒介的運用。BTC 的稀缺性導致人們將其視為一種「數位黃金」或數字價值存儲形式。這種看法的結果是，許多 BTC 持有人不願意將 BTC 用於日常支出。

Pi Coin 的經濟模型設計要求為：

簡潔
一個直觀且透明的模型。
公平分配
讓全世界有大量的人口持有 Pi Coin。
稀缺性
營造稀缺感，使 Pi Coin 在時間的推移中，仍維持其價值。
精英階層的收入
為建立和為維持 Pi Network 而貢獻的人提供獎勵。

Pi Coin Token Emission Policy (Pi Coin 的供應政策)：

Total Max Supply (最大供應量) = M + R + D
a. M = total mining rewards (總挖礦獎勵)
b. R = total referral rewards (總推薦獎勵)
c. D = total developer rewards (總協助開發獎勵)
M = ∫ f(P) dx where f is a logarithmically declining function (該 f 為對數遞減函式)
a. P = Population number (人口數) (e.g., 1st person to join, 2nd person to join, etc.)
R = r * M
a. r = referral rate (推薦率) (50% total or 25% for both referrer and referee)
D = t * (M + R)
t = developer reward rate (開發者獎勵率，25%)

M - 挖礦供應 (為每人鑄造的固定採礦供應)
與為整個世界提供固定硬幣供應的 BTC 不同，Pi Coin 為加入網絡的每個人 (前 1 億參與者) 創建 Pi Coin 的固定供應。換句話說，對於每個加入 Pi Network 的人來說，Pi Coin 的數量都是固定的，這會根據成員的參與程度和對該網路安全的貢獻，為成員終生釋出此供應。
說白一點就是，Pi Coin 的總量，是依據用戶的數量來決定的，用戶越多，則 Pi Coin 上限也將越多，最大上線為 1 億用戶，當超過上限，則 M 將不再增加。
由於 M 的公式是採用「對數遞減函式」，因此也就表示著「越早挖礦的人獎勵越多，隨著人數增長，挖礦獎勵將會遞減」。
2019/09/05 Pi Network 宣布用戶數到達 32.5 萬。
2019/09/25 Pi Network 宣布真實活躍用戶達到 45 萬。
2019/10/10 Pi Network 宣布用戶數到達 65 萬。
2019/10/17 Pi Network 宣布用戶數到達 80 萬。
2019/10/22 Pi Network 宣布用戶數到達 90 萬。
2019/10/25 Pi Network 用戶數到達 100 萬，並且官方刪除了 10 萬 個違規帳號。
2019/10/31 Pi Network 宣布用戶數到達 100 萬，挖礦速度第三次減半。(當用戶數量達到 1000 萬 時，挖礦速度將再次減半。)
2019/11/14 Pi Network 宣布用戶數到達 125 萬。
2019/11/16 Pi Network 發出警告，表示現階段 Pi Coin 尚未開放交易，當前有關 Pi Coin 的交易項目皆可能是詐騙。

R - 推薦人供應量 (為每人鑄造的固定推薦人獎勵，並在推薦人和受推薦人之間共享)
為了使一種貨幣有價值，它必須被廣泛分配。為了激勵這個目標，該協議還生成了固定數量的 Pi Coin 作為推薦人和受推薦人 (或父推薦人、子推薦人)的推薦獎金。各方都在積極挖礦，推薦人和受推薦人都可以利用該礦池，以避免推薦人能夠「掠奪」受推薦人的剝削行為模型。推薦獎金可作為網絡級別的獎勵，以發展 Pi Network，同時還鼓勵成員之間積極參與以確保該網絡的安全。
也就是說，只要多邀請一個人加入 Pi Network，推薦方及受推薦方則各自會多 25% 的挖礦獎勵。

D - 開發者獎勵 (為支持正在進行的開發而創建的附加 Pi Coin)
Pi Coin 將通過「開發者獎勵」為正在進行的開發提供資金，該獎勵與為挖礦和推薦的每枚硬幣同時鑄造。
傳統上，加密貨幣協議產生了固定數量的供應，由於 Pi Coin 的總供應量取決於網絡中的成員數量，因此 Pi Coin 會隨著網絡的擴展逐步獲得開發人員的獎勵。Pi Coin 開發人員獎勵的逐步完善旨在使 Pi Coin 的貢獻者的激勵與網絡的整體健康狀況保持一致。

f - 對數遞減函數 (早期成員賺取更多)
雖然 Pi Coin 試圖避免財富過度的極端集中，但該網絡還試圖以更大比例的 Pi Coin 來獎勵較早的成員及其貢獻。
當像 Pi Network 這樣的網絡在成立之初，它們往往會為參與者提供較低的效用。設想，假設您擁有世界上第一台電話，這將是一項偉大的技術創新，但並非十分有用，不過隨著越來越多的人購買電話，每個電話持有者將從網絡中獲得更多的效用。為了獎勵早日進入網絡的人員，Pi Coin 的個人挖礦獎勵和推薦獎勵隨網絡人數的減少而降低。換句話說，為 Pi Network 中的每個「插槽」保留了一定數量的 Pi Coin。

詳情請查閱 Pi Network White-Paper(Pi Network 白皮書) 原文：

M - Mining Supply (Based on fixed mining supply minted per person)
In contrast to Bitcoin which created a fixed supply of coins for the entire global population, Pi creates a fixed supply of Pi for each person that joins the network up to the first 100 Million participants. In other words, for each person that joins the Pi Network, a fixed amount of Pi is pre-minted. This supply is then released over the lifetime of that member based on their level of engagement and contribution to network security. The supply is released using an exponentially decreasing function similar to Bitcoin’s over the member’s lifetime.
R - Referral Supply (Based on fixed referral reward minted per person and shared b/w referrer and referee)
In order for a currency to have value, it must be widely distributed. To incentivize this goal, the protocol also generates a fixed amount of Pi that serves as a referral bonus for both the referrer and the referee (or both parent and offspring ) This shared pool can be mined by both parties over their lifetime - when both parties are actively mining. Both referrer and referee are able to draw upon this pool in order to avoid exploitative models where referrers are able to “prey” on their referees. The referral bonus serves as a network-level incentive to grow the Pi Network while also incentivizing engagement among members in actively securing the network.
D - Developer Reward Supply (Additional Pi minted to support ongoing development)
Pi will fund its ongoing development with a “Developer Reward” that is minted alongside each coin that is minted for mining and referrals. Traditionally, cryptocurrency protocols have minted a fixed amount of supply that is immediately placed into treasury. Because Pi’s total supply is dependent on the number of members in the network, Pi progressively mints its developer reward as the network scales. The progressive minting of Pi’s developer reward is meant to align the incentives of Pi’s contributors with the overall health of the network.
f is a logarithmically decreasing function - early members earn more
While Pi seeks to avoid extreme concentrations of wealth, the network also seeks to reward earlier members and their contributions with a relatively larger share of Pi. When networks such as Pi are in their early days, they tend to provide a lower utility to participants. For example, imagine having the very first telephone in the world. It would be a great technological innovation but not extremely useful. However, as more people acquire telephones, each telephone holder gets more utility out of the network. In order to reward people that come to the network early, Pi’s individual mining reward and referral rewards decrease as a function of the number of people in the network. In other words, there is a certain amount of Pi that is reserved for each “slot” in the Pi Network.

謠言/爭議
#

一開始有謠言指出，Pi Network 官方表示將在 2020/03/14 將正式啟用第三階段「Mainnet (主網)」。但官方證實為謠言，並表示是在當天開始準備進入第二階段 - Testnet (測試網)。
由於官方要求用戶們必須經過 KYC (實名認證)，在當前 Pi Coin 沒有實質價值時，不少人質疑，Pi Coin 是一場大型的詐騙，許多人認為，這將可能會導致引發一場大型的個資洩漏事件。