In a mechanism for deleting blocks from a blockchain, a retention period (T), a minimum number of blocks (L), and a hash of the oldest block are defined. A participant node creates the new block including a block header. The participant node determines whether a timestamp in an oldest block in the blockchain is older than a current time plus T, and whether a current number of blocks in the blockchain is greater than or equal to L. When both are true, the participant node deletes an oldest block in the blockchain. The participant node adds a hash of an oldest remaining block and an original number of blocks of the blockchain to the block header of the new block. The participant node broadcasts a message announcing the new block to remaining participant nodes of the plurality of participant nodes.