Rateless codes (a.k.a. fountain codes, digital fountain) have found their way in numerous peer-to-peer based applications although their robustness to the so called pollution attack has not been deeply investigated because they have been originally devised as a solution for dealing with block erasures and not for block modification. In this paper we provide an analysis of the intrinsic robustness of three rateless codes algorithms, i.e., random linear network codes (RLNC), Luby transform (LT), and band codes (BC) against intentional data modification. By intrinsic robustness we mean the ability of detecting as soon as possible that modification of at least one equation has occurred as well as the possibility a receiver can decode from the set of equations with and without the modified ones. We focus on bare rateless codes where no additional information is added to equations (e.g., tags) or higher level protocol are used (e.g., verification keys to pre-distribute to receivers) to detect and recover from data modification. We consider several scenarios that combine both random and targeted selection of equations to alter and modification of an equation that can either change the rank of the coding matrix or not. Our analysis reveals that a high percentage of attacks goes undetected unless a minimum code redundancy is achieved, LT codes are the most fragile in virtually all scenarios, RLNC and BC are quite insensitive to the victim selection and type of alteration of chosen equations and exhibit virtually identical robustness although BC offer a low complexity of the decoding algorithm.

无速率代码（又名喷泉代码，数字喷泉）已经在许多基于点对点的应用程序中找到了自己的方式，尽管它们对所谓的污染攻击具有鲁棒性尚未深入研究，因为它们最初是作为处理块擦除而不是块修改的解决方案而设计的。在本文中，我们分析了三种无速率编码算法，即随机线性网络编码 (RLNC)、Luby 变换 (LT) 和波段编码 (BC) 对故意数据修改的内在鲁棒性。我们所说的内在鲁棒性是指尽快检测至少一个方程的修改已经发生的能力，以及接收器可以从有和没有修改的方程组中解码的可能性。我们专注于裸无速率代码，其中没有向方程添加额外信息（例如，标签）或使用更高级别的协议（例如，预分发给接收器的验证密钥）来检测数据修改并从数据修改中恢复。我们考虑了几种结合随机和目标选择方程来改变和修改方程的场景，这些方程可以改变或不改变编码矩阵的秩。我们的分析表明，很高比例的攻击除非实现最小代码冗余，否则不会被检测到，LT 代码在几乎所有场景中都是最脆弱的，RLNC 和 BC 对受害者选择和所选方程的更改类型非常不敏感，并且表现出几乎相同的鲁棒性，尽管 BC 提供了低复杂度解码算法。