How to Stake CLO

Cold staking is a protocol that rewards long-term coin holders for staking their Callisto coins.

Holo Token (HOT) Security Audit Report

Holo Token (HOT) Security Audit Report

Here is the report of the Holo Token (HOT) Security Audit performed by the Callisto Network security department in June 2019.

About Callisto Network and the security department

Utilizing Callisto Network capabilities, we have established a free-for-all system of smart-contracts auditing, to this end, Callisto Network has founded the Callisto security department and deploys treasury funds to pay security auditors for auditing smart-contracts, to reduce risk/flaw in smart-contracts and improve the adoption of programmable blockchains for the whole crypto industry.

Holo Token (HOT) specificities

Source code

Disclosure policy




Number of lines


Holo Token (HOT) Security Audit Report

1. Summary

Holo Token smart contract security audit report performed by Callisto Security Audit Department

2. In scope


3. Findings

In total, 3 issues were reported including:

  • 2 low severity issues.
  • 1 owner privileges (the ability of an owner to manipulate contract, may be risky for investors).

No critical security issues were found.

3.1. Known vulnerabilities of ERC-20 token

Severity: low


  1. It is possible to double withdrawal attack. More details here.
  2. 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) );

3.2. Zero address checking

Severity: low


There are no zero address checking in functions setMinter at line 239, setDestroyer at line 269 and mint at line 243.

3.3. Owner privileges

Severity: owner privileges


Owner can mint any amount of tokens and for a long period of time, because he can not finish minting and can set himself as minter.

4. Conclusion

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

5. Revealing audit reports