Providing data for training a machine learning model

It is provided a method for providing data for training a machine learning model. The method is performed in a training data provider (1) and comprises the steps of: obtaining (40) a data structure comprising a chain of delegations, the chain of delegations covering a delegation path from a media capturing device (3) to the training data provider (1) such that, in the chain of delegations, each delegation is a delegation from a delegator to a receiver; sending (42) a key request to a delegation verifier (2), the key request comprising the data structure; receiving (44) a decryption key from the delegation verifier (2); obtaining (46) encrypted media data captured by the media capturing device (3); decrypting (48) the encrypted media data, resulting in decrypted media data; and providing (50) the decrypted media data for training the machine learning model.