There are 3 legal mechanisms for sharing data while ensuring proper credit: 1) licenses, which grant rights through copyright but require attribution; 2) contracts, which establish attribution norms through bilateral agreements but provide less control than licenses; and 3) waivers, which do not require attribution but also do not provide control over downstream use like licenses and contracts. However, none of these mechanisms alone can perfectly balance credit, control, and open sharing since attribution and credit are not precisely defined by law and can vary depending on social norms.