The hedge fund deploys Shamir's Secret Sharing algorithm:
"The private key itself is AES-256 encrypted. After exporting Bitcoin private keys from wallet.dat file, data is stored in a TrueCrypt container on three separate flash drives. Using Shamir’s Secret Sharing algorithm, the container password is then split into three parts utilizing a 2-of-3 secret sharing model. Incorporating physical security with electronic security, each flash drive from various manufacturers is duplicated several times and, together with a CD-ROM, those items are vaulted in a bank safety deposit box in three different legal jurisdictions. To leverage geographic distribution as well, each bank stores only part of a key, so if a single deposit box is compromised, no funds are lost."
"The private key itself is AES-256 encrypted. After exporting Bitcoin private keys from wallet.dat file, data is stored in a TrueCrypt container on three separate flash drives. Using Shamir’s Secret Sharing algorithm, the container password is then split into three parts utilizing a 2-of-3 secret sharing model. Incorporating physical security with electronic security, each flash drive from various manufacturers is duplicated several times and, together with a CD-ROM, those items are vaulted in a bank safety deposit box in three different legal jurisdictions. To leverage geographic distribution as well, each bank stores only part of a key, so if a single deposit box is compromised, no funds are lost."