Create an encryption key stored in a file You can use a file as a key store. Each file holds a single encryption key. Before you begin You must create the encryption key separately. The name of the key file must match the key alias specified in the encryption keys table in the instance. Procedure Create a file store. OptionDescription AES 128 Place the encryption key, exactly 16 bytes, into the file. AES 256 Place the encryption key, exactly 32 bytes, into the file.