How to fix 51% attacks on (distributed) blockchains

distributed Blockchains on quorum base are vulnerable if one party controlls over 50% of the mining power.
My solution for this problem is, that not all mining is anonymous. Some miners are registered and sign their blocks extra with a public and verified certificate.
For the sacrifice of anonymity they get more share (at least 51%) or are in other models required for some block verifications. The clients are not affected.
If different mining pools are under the control of the same party, they get no extra share as it is easily detect and blockable because they are not anonymous.