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Introduction to EVVM Signature Structures

All EVVM operations require cryptographic signatures for security. This guide explains the universal signature format used across all EVVM services.

Universal Message Format​

Every EVVM signature follows this standardized structure:

<evvmId>,<functionName>,<param1>,<param2>,...,<paramN>

Components:

  • <evvmId>: Network identifier (typically 1)
  • <functionName>: Operation to execute (pay, registerUsername, etc.)
  • <param1>, <param2>...: Function parameters in exact order

EIP-191 Message Signing​

EVVM uses the EIP-191 standard - the same protocol used by MetaMask and other Ethereum wallets.

How it works:

  1. Build your message: 1,pay,0x742c...,0x0000...,50000000000000000,1000000000000000,42,false,0x0000...
  2. EIP-191 wraps it: "\x19Ethereum Signed Message:\n145" + message
  3. Wallet creates signature from the wrapped message

This prevents signatures from being used on other systems or contracts.

Parameter Formatting Rules​

All parameters must be converted to strings:

  • Numbers: 50000000000000000 (decimal, no separators)
  • Addresses: 0x742c7b6b472c8f4bd58e6f9f6c82e8e6e7c82d8c (lowercase hex with 0x)
  • Strings: alice (as provided)
  • Booleans: true or false (lowercase)
  • Bytes: 0xa1b2c3d4... (hex with 0x)

Message Construction Process​

  1. Convert Parameters: Transform all values to proper string format
  2. Concatenate: Join with commas in exact parameter order
  3. Sign: Use wallet to create EIP-191 signature

Example: Payment Transaction​

Scenario: Send 0.05 ETH to another user

Function Parameters:

  1. Recipient: 0x742c7b6b472c8f4bd58e6f9f6c82e8e6e7c82d8c
  2. Token: 0x0000000000000000000000000000000000000000 (ETH)
  3. Amount: 50000000000000000 (0.05 ETH in wei)
  4. Priority Fee: 1000000000000000 (0.001 ETH)
  5. Nonce: 42
  6. Priority Flag: false (sync execution)
  7. Executor: 0x0000000000000000000000000000000000000000 (unrestricted)

Constructed Message:

1,pay,0x742c7b6b472c8f4bd58e6f9f6c82e8e6e7c82d8c,0x0000000000000000000000000000000000000000,50000000000000000,1000000000000000,42,false,0x0000000000000000000000000000000000000000

Username Alternative: Replace address with username alice:

1,pay,alice,0x0000000000000000000000000000000000000000,50000000000000000,1000000000000000,42,false,0x0000000000000000000000000000000000000000

EVVM Services Overview​

EVVM Core Functions​

Payments and transfers:

  • Single payments to addresses or usernames
  • Batch payments to multiple recipients
  • Withdrawal operations (coming soon)

Name Service Functions​

Username management:

  • Registration (pre-register → register process)
  • Marketplace (make/withdraw/accept offers)
  • Metadata management and renewal

Staking Functions​

Token staking operations:

  • Public and presale staking/unstaking
  • Reward claiming and management

Treasury Functions​

Cross-chain operations:

  • Bridge transfers between blockchains
  • Asset management across networks

Important Rules​

  • Parameter Order: Must match exact function specification
  • Nonce Usage: Each signature requires unique nonce per service
  • Format Precision: No extra spaces, correct case sensitivity
  • Address Format: Always lowercase with 0x prefix