Gary Gensler’s push for the Securities and Exchange Commission to get tough on cryptocurrencies is drawing a rebuke from a key GOP lawmaker. Senator Pat Toomey, the top Republican on the Senate Banking Committee, blasted Gensler for trying to regulate the digital-asset industry “by enforcement.” Toomey chided Gensler at a Tuesday hearing for not being more transparent about how the SEC determines whether a digital asset is a security that is subject to tough investor-protection rules.