Examples are described for dynamically applying a digital watermark to a file, such as a dataset of genomic sequencing data. In one example, a method of dynamically applying a watermark to at least a portion of a file includes generating, using a secret key, a first random seed, generating, using the first random seed, an ordered pseudorandom set of integers, generating, using entity information and timing information, a second random seed, selecting, using the second random seed, a subset of the ordered pseudorandom set of integers, and modifying data at data locations in the file corresponding to at least a portion of the identifiers included in the subset to generate a watermarked file. The method may further include performing a check to determine whether the watermark is present in a file using a sequence of watermark elements that are generated based on the secret key.