Beam (BEAM)

1. What is Beam (BEAM)?

Beam is a privacy coin that aims to explore confidential DeFi. It utilizes the Mimblewimble protocol which conceals the values and metadata of transactions, while reducing blockchain bloating and improving scalability. With the latest implementation of LelantusMW it aims to bring privacy and anonymity in all fronts.

Beam's mission is to let users have complete control over their money. The team is building a new blockchain to provide confidential, decentralized and usable store of value and medium of exchange, as well as a strong self-governed community to further develop and support it.

2. Blockchain and network data

MimbleWimble and UTXO model

Beam is based on MimbleWimble, a protocol that allows full confidentiality of blockchain transactions without compromising scalability. Similar to Bitcoin, the MimbleWimble blockchain is based on the Unspent Transaction Ourput ("UTXO") model. However, in MimbleWimble there are no addresses, and UTXO values are encrypted by the "blinding factors". Blinding factors are private keys which are only known to the UTXO owner. It is not possible for an observer to deduce any information on ownership or value of a Beam UTXO.

Each user holds keys to their UTXOs

To create a transaction, the sender and the receiver wallets need to first establish communication. Once the communication is established, the sender provides the transaction inputs, and both sender and receiver create their respective outputs with range proofs attesting that the values are non-negative. Both parties sign the transaction and then it is sent out to the nodes.

Transaction schematics

Secure Bulletin Board System (SBBS)

Beam is built on the Mimblewimble protocol, whuch that achieves confidentiality while significantly improving blockchain scalability. However, in Mimblewimble there are no addresses, and transactions need to be built interactively by the participating parties. That poses a challenge: if Alice wants to send money to Bob, both of their wallets have to connect and perform necessary actions. Creating a direct socket connection every time is impractical while most users depend on Network Address Translations (NATs). Beam’s Secure Bulletin Board (SBBS) system solves this problem and makes the user experience similar to that of Bitcoin and other existing cryptocurrencies.

Dandelion schematics

The nodes verify that the sum of inputs and outputs is exactly zero and that the range proofs and signatures are correct. The inputs are then removed from the current UTXO set, and the outputs are saved.

To improve scalability, the MimbleWimble protocol utilizes the Transaction Cut-Through mechanism. For Beam, the intermediate states of the blockchain are not saved. The blockchain only holds the current state of the UTXO set, and thus does not have to grow linearly with the number of transactions.

As an additional privacy mechanism, Beam implements Dandelion. With Dandelion, transactions are not broadcasted to all nodes immediately. Instead, each transaction is passed through several nodes before being broadcasted to the whole network. At each step of the stem phase, the transaction is merged with other transactions arriving at the same nodes, with the addition of special decoy outputs for better obfuscation.

Lelantus-MW

With the Breaking Linkability feature at heart of Lelantus-MW, it is designed to provide maximum privacy when transacting Beam. An extra layer of protection is added to Beam’s already default privacy and allows users to unlink any potential connections between their transactions, further protecting users' privacy against attackers.

Breaking Linkability is already active on the Beam CLI wallet and in the future ill be introduced to the GUI wallets Lelantus-MW, which brings an anonymity set of 64,000.

Offline transactions

Offline transactions are not a given on any Mimblewimble implementation as by nature this protocol is interactive. Offline transactions are enabled through the Lelantus MW protocol implemented on Beam on the 5.1 wallet version.

Proof-of-Work (PoW) consensus with ASIC resistance

For consensus, Beam uses Beam Hash, a Proof-of-Work algorithm based on Equihash.

When Beam launched on Jan 3, 2019, it was announced that Beam will perform two hard forks. The rationale was to signal to ASIC developers that there is no point to start developing ASICs until the second hard fork is out. Beam timed the first fork roughly 6 months from launch, and the second one in mid 2020. The 10-month timeframe is chosen considering how long it usually takes to develop a new ASIC chip.

BeamHash III is an improvement to the Beam mining network and is it better for GPU mining and GPU miners, as memory-consuming operations in the design of BeamHash III allow better use of the fuller capabilities of a GPU card. The stronger algorithm binding of the new scheme utilized in BeamHash III aims to make "unknown optimisations" potentially used for secret mining more unlikely.

3. Economics and supply

3.1 Key metrics

3.2 Token supply distribution

The token distribution was as follows:

• Private Sale 1 tokens make up 2.40% of the total token supply. It was conducted between May to June 2018, raised a total of 2.02MM USDT at $0.32 per coin, selling 2.40% of the total token supply.
• Private Sale 2 tokens make up 1.20% of the total token supply. It was conducted between July to September 2018, raised a total of 2.02MM USDT at $0.64 per coin, selling 1.20% of the total token supply.
• Private Sale 3 tokens make up 0.55% of the total token supply. It was conducted between October to December 2018, raised a total of 1.15MM USDT at $0.80 per coin, selling 0.55% of the total token supply.
• Team owns 4.80% of the total token supply.
• Beam Foundation tokens consist of 2.40% of the total token supply.
• Advisors received 0.65% of the total token supply.
• Mining Rewards tokens make up 88.00% of the total token supply.

BEAM token distribution (%)

BEAM is designed to be a deflationary coin with capped supply, halving every four years, and stopping emission altogether after 133 years.

BEAM emission schedule is largely inspired by Bitcoin's. The main differences are that there are 10 times more blocks and that BEAM's first-year emission is 100 BEAM coins per block. The first halving occurs after 1 year, and then halvings occur every 4 years, 33 times in total.

The emission is of BEAM is denominated in Groth, the smallest unit of BEAM. One BEAM contains 100,000,000 Groth.

In the first 5 years, BEAM emission is split between Mining Rewards and the Token Treasury:

• Mining Rewards: in the first year, Mining Rewards will be 80 coins per block. In years 2–5, Mining Rewards will be 40 coins per block. In year 6, Mining Rewards will be reduced to 25 coins, and then halving will occur every 4 years until year 129. After year 133, BEAM emission will stop.
• Token Treasury: in the first year, 20 BEAM coins per block are emitted to the Token Treasury, and in the second to fifth year, the Treasury will receive 10 coins per block. The Token Treasury will be used to repay investors (Private Sale 1, 2, and 3), incentivize the Team and Advisors, and to support the Beam Foundation.

The emission curve of BEAM is shown below, which can also be found in this article:

3.3 Token governance and use of funds

Beam Foundation was set up during late 2019, and uses the funds allocated to it in Beam Treasury to support the development of the Beam protocol and to promote the wider privacy-related agenda.

The private keys to the Team and Foundation wallets are held in secured vaults with 24/7 security. Opening the vault requires physical keys from two of Beam's core team members.

4. Roadmap, updates, and business development

For the most updated Beam roadmap, see here.

4.1 Original Roadmap

5. Project team

6. Beam's activity and community overview

6.1 Development activity

Beam has a combination of public and private repositories.

6.2 Social and community data

Beam's community growth strategy is structured around 4 community groups: ambassadors, developers, miners, and privacy-tech advocates.

To foster the growth of its community, the team relies on multiple elements:

• An ambassador program: The team currently has more than 30 volunteers that are responsible for building and managing local communities.
• Active participation in conferences and events: The team has been active in blockchain events and conferences all over the world, including: Token2049, Slush Japan, Deconomy, Distribute, North America Blockchain Week, Consensus NYC.
• An online academic program: the team runs its academic program in the US to interact with Blockchain Student Associations, currently including that of Harward, Yale, Columbia, UCLA, Stanford, MIT, Carnegie Mellon, etc. The Academic Program will expand to Asia in the near future.
• Online hackathons: The team conducted an online hackathon with Qtum in summer 2019. Another hackathon will be held in September in Germany with Blockmania.
• Gamification of the mining process: Beam states that their strategy with miners will focus on gamification of the mining process.

Telegram (English)
Twitter (English)
Medium (English)
Reddit
Youtube

7. Appendix

References

• Bright Boson (v2.1.4910)
• Fast Sync
• Proof of Payment
• One side Payments
• Sparse Blocks
• Atomic Swap Demo
• Cold Wallet Implementation

Advisors

• Beni Issembert (CMO at Concordium)
• Gordon Chen (Co-Founder and CEO at Neutral)
• Bryan Bishop (Bitcoin developer at LedgerX)
• Maja Vujinovic (CEO at OGroup)
• Rami Kasterstein (Co-Founder and Board member at Spacemesh)
• Liraz Siri (CEO at TabooKey)
• Addison Huegel (Principal at BlockGroup)
• Oliver Gale (Founder at Bitt and BaseTwo)
• Marshall Ball (Cryptography researcher at Columbia and Tel Aviv University)