How to setup Oracle Network Integrity

Encryption will protect your data from being read in clear text, when in transition.
However, data can still be tampered with and arrive modified at the receiver's end.

To protect against modification, you need to ensure the integrity of the data being sent over the network.

Data integrity protection from Oracle works independently from the encryption process. In other words, you can use both encryption and checksuming together or either one separately.

To implement network integrity, add the following to your server’s sqlnet.ora file:

SQLNET.CRYPTO_CHECKSUM_SERVER = requested
SQLNET.CRYPTO_CHECKSUM_TYPES_SERVER= (SHA256, SHA384, SHA512, SHA1, MD5)

All of the hash algorithms in the list create a checksum that changes if the data is altered in any way.

The value "requested" in the CRYPTO_CHECKSUM_SERVER instructs the Oracle server that calculating checksums when sending network packets to the client is desirable, but not required. Other valid settings are "required", "accepted" and "rejected". See the documentation for details.

The list of available encryption algorithms are stated in the CRYPTO_CHECKSUM_TYPE_SERVER, and the first one common to both client and server in the list will be selected. During my tests, the SHA256 was selected.

More information is to be found in the official documentation