RenVM utilizes an approach called tokenized representation. This process allows you to lock up an asset and mint a one-to-one representation of that asset in return, typically in the form of an ERC-20 token. You can then burn this tokenized asset to redeem your locked asset. RenVM does not utilize a centralized custodian to hold the locked assets; instead, it uses a novel security model reliant on a network of private and randomly grouped nodes to ensure privacy.