True NFT Stage 0 Formal Verification Proposal

Contest Proposal: TrueNFT Smart Contract Informal Audit

Short Description

The contestants shall provide the informal audit of the central TrueNFT smart contracts (content of true-nft-core directory), hereinafter referred to as “smart contracts”, where the detailed description of the “informal audit” is described below. All debot contracts are excluded from the present contest.


Ideally speaking, all smart contracts issued by the Free TON ecosystem must pass the formal verification process. However, as the formal verification is an extremely time-consuming process, in some cases the business cannot wait for such a long time. Additionally, each bug found during the formal verification requires a major rework of the whole underlying stuff already completed.

To address both above-mentioned issues, we suggest undertaking the informal audit before proceeding to formal verification. Being capable to find most bugs, the completion of this kind of activity allows us to:

  • Release a smart contract with a high (but not the highest) level of reliability (this should be undertaken exclusively in a case of a strong business need)
  • Dramatically decrease the likelihood of finding a bug during the formal verification (taking into account that each bug found at the formal verification stage brings major overhead for the proving system)


Before entering the informal audit process, each smart contract must comply with the following rules:

  • The smart contract must be compilable with the latest version of tondev tool
  • All smart contracts must be submitted with detailed documentation
  • The smart contract’s developers must set up a Telegram group for discussions as well as a slot for one-hour voice meetings at least once a week
  • All the smart contracts being audited must be covered by unit and integration tests
  • All the tests must pass


The source code is available at at branch master with hash code equal to d7dabed756d28582450ea2e7d2a964fbd19d4c29.

Contest Terms

Contestants shall submit a document in PDF format that covers:

● All the errors found

● All the warnings found

● All the “bad code” (long functions, violation of abstraction levels, poor readability etc.)


Errors and warnings should be submitted to the developers as early as possible, during the

contest, so that the code can be fixed immediately.

In case the code is modified (due to errors and warnings found by the participants or due to any other reasons) not later than one week before the end of the contests the participants are encouraged to take these modifications into account.

The document should also contain a high-level description of the code, and any information

showing that the contest had a good understanding of the infrastructure and of the code.

Contest Dates

7 Sep 2021 - 24 Sep 2021

Proposed Prices

The total contest budget is 100 kTON, whereby 95% are allocated to the contestant awards and 5% are allocated to the jury reward.

The contestant awards are distributed as follows:

  • Place 1 - 50 kTON
  • Place 2 - 30 kTON
  • Place 3 - 15 kTON

The Jury

The Jury shall be formed from acknowledged experts in the fields of security, smart contract audit, and formal verification fields, whereby:

  • Jurors whose team(s) intend to provide submissions in this contest shall lose their right to vote in this contest
  • Each juror shall vote by rating each submission on a scale of 0 to 10 (0 equalling rejection of the proposal); a juror may abstain from voting if they do not see themselves sufficiently qualified to judge such proposal
  • A juror that has voted on a submission shall provide detailed feedback on it

Jury Guidelines

  • The main goal of the jury is to check how the provided audit is useful in terms of decreasing the bug risk for the contract being audited
  • All the requirements mentioned above are considered as mandatory otherwise some points have to be taken from the corresponding application
  • The usage of industry-adopted 3rd party tools should bring additional points in case the motivation of their usage has been clearly demonstrated
  • Any team that managed to find a non-minor bug must be placed higher than a team that failed to do it
  • Any bugs related to the kind of the exceptions as well those related to the logging or retrieving the state are considered as minor and should not be taken into account for the ranking

Jury Rewards

The total budget for jury rewards is 5% of the above-mentioned contest reward budget, or

5 kTON.

This amount shall be distributed between jurors who have voted and provided feedback on submissions.

The proportion of the total budget assigned to a juror shall be defined according to the extent of this juror’s participation in the contest, i.e. the count of votes cast by this juror divided by the total votes cast count for this contest.

Procedural Limitations

  • Only one submission per contestant shall be accepted. Multiple submissions, including but not limited to updated versions of the initial submission, are not allowed.
  • Submissions shall be made within the time frame defined above in the Contest Dates section. Late submissions shall be rejected by the Jury.
  • All submissions shall contain the contestant’s contact information (preferably a Telegram ID) to ensure that the jury can match the submission to the specific contestant. If such contact information is missing, the submission shall be rejected.
  • If the submission contains links to external material (reports on further work by the contestant), this material shall have the contestant’s contact details (preferably a Telegram ID), to ensure that the jury can match the material to the specific contestant. If such contact information is missing, the submission shall be rejected.


Anyone can participate, but Free TON cannot distribute tokens to US citizens or US entities.

Pruvendo team is going to submit its report in a few minutes. Please address all your questions via Telegram to @SergeyEgorovSPb

Hi! Here’s my submission.
Description : (attached to contest submission);
Telegram : @SuperArmor
Wallet : 0:cba39007bdb0f025aac0609b25e96a7d2153f06d22fa47b5f6c26cf756b8b2d6

Contest Submission Extension: True NFT Stage 0 Formal Verification Proposal

One of the audits was not submitted on time. We propose an extension
of the submission deadline to submit this work (and maybe other late


#17 Contest Proposal : TrueNFT Smart Contract Informal Audit

New submission deadline

Tuesday, Sep 28th, 2021, 23:59


New accepted submissions submitted in this deadline extension will
receive smaller rewards than accepted submissions that were
submitted before the extension (the accepted submissions are the
ones that received an average score of at least 6).

Extending contest submission deadline is unfair to the the contestants that submitted their works on time. It also creates a precedent that contest rules may be bent or changed if someone needs that, thus lowering the trust to the whole contest system of FreeTON.