OEURO

Denis Bouzon

01 · OEURO — Essential Parameters

Decimals 6 On-chain precision

P2P fee 0.15% Deducted from transferred amount

Gross minimum 0.501 OEURO Ordinary P2P transfer

Oracle request 24 hours Execution window

Circulation EOA → EOA Delegated transfers disabled

Settlement Manager-gated Oracle cannot mint or burn directly

Reference testnet Sei Testnet · Chain ID 1328 0x49A0D9D353e9b9860B137DFAA7f24ab83E14c7f7

02 · OEURO on Sei Testnet

OEURO Version 2.0 has a public reference deployment on Sei Testnet for development, integration testing, wallet validation and pre-audit review. The deployed contract is publicly inspectable and its source has been verified on SeiScan with matching bytecode and ABI.

Network: Sei Testnet · EVM Chain ID 1328 (0x530)
Native gas asset: SEI
Contract: OsniasClearing_Oeuro
Contract address: 0x49A0D9D353e9b9860B137DFAA7f24ab83E14c7f7
Creation transaction: 0x97dfa508843181c4649215389c6be24f626b3510bb507d531a73e36255c37043

View verified OEURO contract on SeiScan → View creation transaction →

03 · Technical Role

A clearing register, not a market token

OEURO is designed for one specific function: representing and transferring a EUR-denominated clearing unit between user accounts. The token contract is intentionally restricted so that its ordinary circulation remains focused on direct account-to-account clearing.

Clearing

Direct P2P transfer

The normal operational path is a direct transfer from one EOA user account to another EOA user account.

Controlled supply

Explicit mint / burn

Supply changes only through explicit mint and burn paths controlled by the manager, either manually or after a valid oracle request.

Restricted integration

No delegated transfer path

The reference implementation disables approve() and transferFrom() and rejects ordinary transfers to smart-contract recipients.

04 · P2P Circulation

Gross debited / net received

For an ordinary user transfer, the sender is debited exactly the gross amount entered. A 0.15% protocol fee is deducted inside that amount and credited to the feeRecipient. The beneficiary receives the remaining net amount.

1,000.000000 OEURO

Gross amount requested by the sender.

1.500000 OEURO

0.15% protocol fee credited to the feeRecipient.

998.500000 OEURO

Net amount received by the beneficiary.

Transfer invariant. Sender debit = beneficiary credit + feeRecipient credit. The transfer-fee mechanism redistributes existing OEURO and does not create additional supply.

Ordinary circulation

EOA → EOA transfers.
Gross amount ≥ 0.501 OEURO.
0.15% protocol fee.
Restricted-recipient rules apply.

Disabled paths

approve() is disabled.
transferFrom() is disabled.
Ordinary transfer to a smart contract is rejected.
Minting to a smart-contract address is rejected by the reference implementation.

05 · Clearing / Custody Segregation

Clearing and deposit are separate operational domains

The OEURO smart contract is a clearing register. It does not receive or hold customer deposits and contains no customer-custody, lending, collateral-management, withdrawal or bank-account logic. Deposit and custody functions remain outside OEURO and are handled by separately identified external partners.

Clearing layer

OEURO records and settles EUR-denominated clearing units between eligible user-controlled accounts. Its supply and settlement functions remain governed by the OEURO manager/oracle architecture.

External collateral layer

EURC by Circle — recommended

Where an external EUR-denominated escrow or custody arrangement is used, EURC issued by Circle is the recommended collateral asset. EURC custody, redemption and collateral management remain outside the OEURO smart contract and confer no mint, burn, oracle or manager authority over OEURO.

Strict segregation principle. OEURO performs clearing; external escrow/custody partners perform deposit and collateral functions. The two operational domains are deliberately separated.

06 · Oracle & Settlement

The oracle attests. The manager settles.

An authorized oracle cannot directly mint or burn OEURO. It creates an on-chain MINT or BURN request after observing or verifying an external event. Only the manager can execute or permanently reject that request.

1 · Attestation

An authorized oracle validates an external event and submits a request containing the account, amount, source chain and external reference.

2 · Pending

The request is recorded on-chain with a timestamp and remains executable for 24 hours.

3 · Settlement

The manager executes or rejects the request. An expired request can no longer be executed.

Oracle authority

Request only

The oracle can attest and request; it cannot directly modify OEURO supply.

Anti-replay

Single-use proof

The same source-chain / external-reference pair can be consumed only once. Rejection does not make the proof reusable.

Finality

Terminal state

Executed and rejected requests remain identifiable through their final on-chain status and emitted events.

07 · Technical Specification

OEURO token design

Open OEURO Technical Documentation · PDF ↗

Full name	Osnias Euro Clearing.
Symbol	OEuro.
Solidity	^0.8.22 in the reference implementation.
Public reference network	Sei Testnet · EVM Chain ID 1328 (0x530) · native gas asset SEI.
Verified contract	0x49A0D9D353e9b9860B137DFAA7f24ab83E14c7f7
Creation transaction	0x97dfa508843181c4649215389c6be24f626b3510bb507d531a73e36255c37043
Compiler / optimizer	Solidity v0.8.22+commit.4fc1097e · optimizer enabled · 200 runs · EVM target Paris.
Explorer verification	SeiScan · matching bytecode and ABI.
External escrow collateral	EURC issued by Circle is recommended for external EUR-denominated escrow/custody arrangements; custody remains outside OEURO.
Base standard	OpenZeppelin ERC-20 with Ownable2Step administration.
Decimals	6.
Minimum ordinary transfer	501,000 base units = 0.501000 OEURO gross.
Protocol fee	15 basis points = 0.15%, deducted from the gross transferred amount.
Ordinary circulation	Direct EOA → EOA transfer, subject to minimum amount and recipient restrictions.
approve / transferFrom	Disabled in the reference implementation.
Manual mint / burn	Manager-only.
Oracle request	MINT or BURN request, valid for 24 hours.
Oracle settlement	Execution or rejection reserved to the manager.
Anti-replay	A sourceChain + externalRef proof pair can be consumed only once.
Fee recipient	Configurable by the manager; must be an EOA in the reference implementation.
Restricted recipients	The initial manager, GasPool and authorized oracles are prevented from receiving ordinary OEURO transfers under the current reference design.

08 · Security Invariants

Explicit trust boundaries

Supply

Explicit supply paths

Minting and burning are limited to clearly identified manager-authorized functions.

Oracle

Separation of powers

Compromise of an oracle alone is insufficient to mint or burn OEURO because final settlement remains manager-gated.

Proof integrity

Anti-replay

An external proof cannot be used to create multiple OEURO requests.

Transfer accounting

Conservation

Ordinary transfer fees redistribute existing OEURO between the beneficiary and feeRecipient without fee-induced inflation.

Recipient policy

EOA-focused design

Ordinary transfers to smart contracts are rejected, keeping the normal clearing path account-to-account.

Administration

Two-step ownership

Ownable2Step provides an explicit acceptance step when administrative ownership is transferred.

09 · Transparency

Public source, ABI and flattened contract

OEURO technical files are publicly accessible from the /oeuro/ repository directory. The links below point to the current public technical package.

Permanent technical archive — Zenodo. OEURO Version 2.0 is permanently archived on Zenodo under DOI 10.5281/zenodo.22195130. The archive contains the Solidity source code, ABI, flattened contract and the OEURO Technical White Paper & Audit Reference.

oeuro-sei-testnet-main.sol Reference Solidity source

SOURCE ↗

oeuro-sei-testnet.abi Public contract ABI

ABI ↗

oeuro-sei-testnet-flat.sol Flattened Solidity source for technical review

FLAT ↗

Sei Testnet — verified OEURO contract 0x49A0D9D353e9b9860B137DFAA7f24ab83E14c7f7

SEISCAN ↗

OEURO_Technical_White_Paper.pdf OEURO Technical White Paper & Audit Reference

PDF ↗

Reference testnet deployment — Sei Testnet. OEURO Version 2.0 reference address: 0x49A0D9D353e9b9860B137DFAA7f24ab83E14c7f7. Source verification on SeiScan produced matching bytecode and ABI. The creation transaction is 0x97dfa508843181c4649215389c6be24f626b3510bb507d531a73e36255c37043.

Document scope. The OEURO Technical White Paper describes the token architecture, deployment model, smart-contract behavior, operational roles, security boundaries and audit invariants. Legal, regulatory, contractual and compliance matters are addressed separately in dedicated Osnias Clearing regulatory documentation.