How can a miner establish an identity in a way that's hard to fake? (i. e., anyone can tell which blocks were mined by her.)

Clunker motors inc. is recalling all vehicles in its extravagant line from model years 1999—2002 as well as all vehicles in its guzzler line from model years 2004—2007. a boolean variable named recalled has been declared. given a variable modelyear and a string modelname, write a statement that assigns true to recalled if the values of modelyear and modelname match the recall details and assigns false otherwise.