Crypto-communism is a secret support for, or admiration of communism. An individual or group keeps this support or admiration hidden to avoid political persecution or political suicide. Crypto-Bolshevism is synonymous, asserting secret Bolshevism.
In the United States, the labels of crypto-communist and crypto-fascist have often been pejoratively applied by political opponents, implying that anyone who supports a particular policy must be secretly extremist.
References
Crypto-communism Wikipedia(Text) CC BY-SA