To provide an information recorder or the like capable of preventing content data from being unauthorizedly used by securely concealing secret data from an unauthorized reproduction.

An information recording and reproduction device 200 selects a physical address of a specific ECC block 10P as a specific block address on the basis of prescribed unique identification information when recording the specific ECC block 10P in an information recording medium 300. Then, the information recording and reproduction device 200 selects an error data string, error data and a position in the specific ECC block 10P of secret data on the basis of the prescribed unique identification information and the selected specific block address, and embeds the error data and the secret data in the specific ECC block 10P.