Unable to recover the confidential data passphrase while installing HP ALM 12.53

We are upgrading ALM from 11.52 to 12.53. But we dont have the confidential data passphrase used in ALM 11.52. We have tried to recover the data passphrase by following the steps as mentioned in ALM 12.53 install guide (page 93). But the passphrase is not displayed when we reaches the security page of installation wizard. The user used for installation have admin access in application and database server. Please help in resolving this issue.