The post discusses the Denial of Service or alias the DoS attack. The Denial of Service (hence referred to as DoS) restricts legitimate users from using the smart contracts permanently or for a certain period unusable. In the blockchain, DoS attacks are of three types, namely: Unexpected Revert, Block Gas Limit, and Block Stuffing. For […]
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In this post, we discuss phishing attacks due to tx.origin. In the regular phishing of a website, phishing begins with a phony email or another kind of communication intended to entice a victim. In this case, the communication done appears as if it came from a reputable sender. Similarly, the case of smart contracts which
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You can check out the code for this article on our GitHub. Preamble The post discusses the next attack called the reentrancy attack. One famous reentrancy attack that occurred in 2016 was the DAO attack leading to losses of $60 million. Let us try to emulate the attack and see the possible solutions for such
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In this part 2 of the series, we’ll examine how to exploit the “private” vulnerability in Solidity. As the name suggests, private means not accessible to anyone outside. Can we expect the same in Solidity smart contracts? Is any variable declared as ” private” in Solidity is not accessible from the outside world? If the
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Unlike mobile and web development, in which software can be upgraded easily to fix any security loopholes, the same is arduous if not impossible in the field of blockchain, smart contracts in particular. The cost of failure in blockchain can be extremely high as a lot of currency is at stake. Keeping this in mind,
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You can check out the slides here (direct PDF link): What is Backtracking? Backtracking is a general approach, i.e. a variant of a depth-first search algorithm, suited for solving constraint satisfaction problems. ???? Idea: Backtracking incrementally validates candidates, tests the solutions, and backtracks from a candidate value if it determines that the final solution is
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As you watch the video, you can have a look at the slides as PDF: download slides in a new tab here. What is the Jump Point Search Algorithm? The jump point search algorithm — or shorter JPS — is a variant of the A* search algorithm, optimized for pathfinding on grid maps, i.e., in
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This tutorial guides you into the fascinating A* (A-Star) using the Python programming language. First, feel free to watch the video guide—we’ll give a detailed textual explanation below. The slides can be found as a Gif here: Okay, so let’s dive into the algorithm motivation, explanation, and Python code next! What is the A* Search
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You can download the PDF file of the presentation here. Also, watch the presentation as a Gif here: What is Dijkstra’s Algorithm? Dijkstra’s algorithm solves the single-source shortest path (SSSP) problem. Generally, it enables finding the shortest route between two vertices in a graph. Its author is dr. Edsger W. Dijkstra, a pioneering contributor to
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You can watch the slides as a GIF here: And download the slides as PDF here. What’s the Best-First Search Algorithm? After several articles on uninformed search algorithms, we continue our journey to informed search algorithms. The first one in the series is the Best-First search algorithm. In general, informed search algorithms use some kind
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