EIP-3198: BASEFEE opcode


  Ethereum Improvement Proposals
        
        
          
            
              
            
          
        

        AllCoreNetworkingInterfaceERCMetaInformational

      



      
        
  
    

  
    
    
    
    
    
      Standards Track: Core
    
  
  
    
      EIP-3198: BASEFEE opcode
    
    
      
        
      
    
    
      
        
      
    
  

  

  	Authors	Abdelhamid Bakhta (@abdelhamidbakhta), Vitalik Buterin (@vbuterin)
	Created	2021-01-13
	Requires	

  EIP-1559




  


  

  
    Table of Contents

    	Simple Summary
	Abstract
	Motivation
	Specification
	Rationale
    	Gas cost


  
	Backwards Compatibility
	Test Cases
    	Nominal case


  
	Security Considerations
	Copyright



  


  
      
      
         Simple Summary
      
      
    

Adds an opcode that gives the EVM access to the block’s base fee.

  
    
      
      
         Abstract
      
      
    


Add a BASEFEE (0x48) that returns the value of the base fee of the current block it is executing in.

  
    
      
      
         Motivation
      
      
    

The intended use case would be for contracts to get the value of the base fee. This feature would enable or improve existing use cases, such as:

	Contracts that need to set bounties for anyone to “poke” them with a transaction could set the bounty to be BASEFEE + x, or BASEFEE * (1 + x). This makes the mechanism more reliable, because they will always pay “enough” regardless of market conditions.
	Gas futures can be implemented based on it. This would be more precise than gastokens.
	Improve the security for state channels, plasma, optirolls and other fraud proof driven solutions. Having the BASEFEE as an input allows you to lengthen the challenge period automatically if you see that the BASEFEE is high.


  
    
      
      
         Specification
      
      
    

Add a BASEFEE opcode at (0x48), with gas cost G_base.


	Op	Input	Output	Cost
	0x48	0	1	2


  
    
      
      
         Rationale
      
      
    

  
    
      
      
         Gas cost
      
      
    

The value of the base fee is needed to process transactions. That means it’s value is already available before running the EVM code.
The opcode does not add extra complexity and additional read/write operations, hence the choice of G_base gas cost.

  
    
      
      
         Backwards Compatibility
      
      
    

There are no known backward compatibility issues with this opcode.

  
    
      
      
         Test Cases
      
      
    

  
    
      
      
         Nominal case
      
      
    

Assuming current block base fee is 7 wei.
This should push the value 7 (left padded byte32) to the stack.


Bytecode: 0x4800 (BASEFEE, STOP)


	Pc	Op	Cost	Stack	RStack
	0	BASEFEE	2	[]	[]
	1	STOP	0	[7]	[]



Output: 0x
Consumed gas: 2

  
    
      
      
         Security Considerations
      
      
    

The value of the base fee is not sensitive and is publicly accessible in the block header. There are no known security implications with this opcode.

  
    
      
      
         Copyright
      
      
    

Copyright and related rights waived via CC0.


  Citation

  Please cite this document as:

  
  Abdelhamid Bakhta (@abdelhamidbakhta), Vitalik Buterin (@vbuterin), "EIP-3198: BASEFEE opcode," Ethereum Improvement Proposals, no. 3198, January 2021. [Online serial]. Available: https://eips.ethereum.org/EIPS/eip-3198.






      
    
  

  

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