Methods and apparatus are disclosed to identify media using hash keys. An example disclosed method includes generating a hash key based on first samples of media. In the disclosed example method, the first samples corresponds to a portion of the media sampled in a buffer of a computing device. The example method also includes applying a blurring function to the hash key to generate a blurred hash key. The example method also includes generating first confirmation data based on second samples of the media. The example method also includes storing the blurred hash key in association with the first confirmation data and first reference data in a memory separate from the buffer of the sampled media. In the example methods, the reference data identifies the portion of the media.