Introduction

On September 29th, 2017, ABDK Consulting was contacted by the eSports.com development team and was asked to audit a set of smart contracts for the eSports ICO. Given the amount of code for review, ABDK has asked $12000 for the audit, of which 40% must be an advance payment. An agreement was signed by Pietro Seminara, the alleged director of eSports.com LTD with the help of Natalia Stoyanova-Perron. The agreement stipulated that eSports.com has 5 days to file complaints.

Audit

ABDK Consulting has finished the report on October 26th. Among others, a critical flaw was found: the smart contract has some tokens frozen till certain time, but later anyone, not only the legitimate owner could withdraw them. The developers, having seen the report, fixed the mistake saving potentially millions of dollars in tokens for eSports. On October 30th, ABDK has reviewed the corrections to the code made by the developers.

Payment

The payment has never happened, even the advance one. The invoice was sent on November 9th. On November 10th Natalia promised to return to me on Monday [13th]. On 13th she commanded us to contact their CEO Philipp Geppert. When we provided our phone number, on 16th she said “he will call you tomorrow”. On November 18th Philipp promised to contact on Monday-Tuesday [20th-21th]. He did not call. After a reminder on 23th Philipp sent a cryptic message about token naming and mentions that he is very busy. On November 25th he finally called and said he did not see the agreement. He could not provide details on what the problems are. On November 27th we got a message he is on flight to Singapore.


Dmitry Khovratovich,
CEO of ABDK Consulting

For those who does not want to participate in the INS ICO, do not worry: the token contract will be destructed by its end and the tokens will seamlessly disappear from MEW and Etherscan.

We have recently developed a memory-hard proof-of-work, which is based on the well known Generalized Birthday problem: given a list of binary vectors X₁, X₂,..X_N and number k find i1,i2,..ik such that
X_i1 + X_i2 +.. + X_ik =0.

The non-trivial algorithm for it was developed by Wagner in 2001 and has been studied extensively since then.

Our proof-of-work is tunable for time, memory, and time-memory tradeoff independently, and verification is instant. Uniquely, by varying k  any tradeoff resilience level can be chosen (e.g., one may require that the time grows as 4-th power of the memory reduction).

 For example, the proof for 700-MB memory is 148 bytes long. The implementation exists but is not optimized.

In our paper we explore in details all the related time-space tradeoffs, compare the scheme to existing alternatives such as Momentum and Cuckoo, discuss its implementations on ASICs and GPUs, and estimate its performance and bandwidth requirements.

The full paper is available at http://eprint.iacr.org/2015/946

Comments are welcome.

Alex Biryukov
Dmitry Khovratovich