NXP Semiconductors and its academic partners challenged the cryptographic community with finding practical attacks on the block cipher they designed, PRINCE. Instead of trying to attack as many rounds as possible using attacks which are usually impractical despite being faster than brute force, the challenge invites cryptographers to find practical attacks and encourages them to actually implement them. In this paper, we present new attacks on round-reduced PRINCE including the ones which won the challenge in the 4-, 6- and 8-round categories—the highest for which winners were identified. Our first attacks rely on a meet-in-the-middle approach and break up to ten rounds of the cipher. We also describe heuristic methods we used to find practical SAT-based and differential attacks. Finally, we also present an analysis of the cycle structure of the internal rounds of PRINCE leading both to a low complexity distinguisher for 4-round PRINCE-core and an alternative representation of the cipher valid in particular contexts and which highlights, in these cases, a poor diffusion.

中文翻译：

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Round-Reduced PRINCE的中间人攻击和结构分析

恩智浦半导体及其学术合作伙伴向加密社区发起挑战，他们发现了对其设计的分组密码 PRINCE 的实际攻击。挑战尝试使用尽管比蛮力更快但通常不切实际的攻击来尽可能多地进行攻击，而是邀请密码学家找到实际的攻击并鼓励他们实际实施它们。在本文中，我们提出了对减少回合的 PRINCE 的新攻击，包括在 4、6 和 8 轮类别中赢得挑战的攻击 - 确定获胜者的最高级别。我们的第一次攻击依赖于中间相遇的方法并分解多达十轮的密码。我们还描述了我们用来寻找实用的基于 SAT 和差异攻击的启发式方法。最后，