Data Encryption in Lawson

Field-level security: The short answer is no, except for HR, unless you're running LSF 9.0. You can do some things with drill-around security, and with record-level security for certain field conditions, which may or may not accomplish your requirements, but it's generally not worth it.

Of course, you can always upgrade to LSF 9.0, which will apply field-level security (to IOS/Portal, not to LID).

If you're not planning to go there yet, you might want to check out the Machensoft ESBus product, which would probably allow you to do it.

Data encryption - depends where the decryption should happen. If you simply want Oracle DATA to be encrypted, and decryption to be done by Oracle itself at some point of access, Oracle Advanced Security should do it for you. Please, note that performance will suffer somewhat (CPU will be spent on encryption/decryption process).
Note that Advanced Security can encrypt Oracle network connections as well, so encryption may apply even if Oracle is located on a different box.
Note also that this option costs money (it's not free as far as I know, though it MIGHT be included in the Oracle Enterprise Edition).

Lawson does not use data encryption when passing information. So Lawson does not encrypt or decrypt data. Also, portal information is sent over secured sockets, but not encrypted. Clients who are interested in data encryption should implement SSL, which provides data encryption. Lawson products are certified to work with SSL
Data encyption would have to be done by the network or database (SQLPlus) before passing it to Lawson. You can use the Oracle PS/SQL Encryption package to encrypt data. Lawson recommends using encryption at the disk level, so all data would then be encrypted and transparent to the SQL database. Lawson does support the SQL Net encryption, since it is not a Lawson product.