ChainLink Token (LINK) security audit, conducted by the Callisto Network Security Department in April 2019.


ChainLink Token (LINK) Specificities



Token Description

Symbol      : LINK
Name        : ChainLink Token
Total supply: 1,000,000,000
Decimals    : 18 
Standard    : ERC677

Deployed at:

Source Code:



Number of lines:



ChainLink (LINK) Smart Contract Security Audit Report

Are Your Funds Safe?


1. In scope

2. Findings

In total, 2 issues were reported including:

  • 2 low severity issues.

No critical security issues were found.

2.1. Known vulnerabilities of ERC-20 token

Severity: low


  • It is possible to double withdrawal attack. More details here.
  • Lack of transaction handling mechanism issue. WARNING! This is a very common issue and it already caused millions of dollars losses for lots of token users! More details here.


Add the following code to the transfer(_to address, ...) function:

require( _to != address(this) );

2.2. No zero address checking

Severity: low


  • In functions transfer(Line 81) and transferFrom(Line 118) there are no zero address checking.

Code snippet:

3. Conclusion

The audited smart contract can be deployed. Only low severity issues were found during the audit.

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