If your Oracle Client configuration file already includes the encryption method, then DBD:Oracle uses those settings to encrypt the connection while you extract the data. For example, if you have configured the Oracle Client configuration file (sqlnet.or or .sqlnet) with the following information:

# Configure encryption of connections to Oracle
SQLNET.ENCRYPTION_CLIENT = required
SQLNET.ENCRYPTION_TYPES_CLIENT = (AES256, RC4_256)
SQLNET.CRYPTO_SEED = 'should be 10-70 random characters'

Any tool that uses the Oracle client to talk to the database will be encrypted if you set up session encryption like above.

For example, Perl DBI uses DBD-Oracle, which uses the Oracle client for actually handling database communication. If the installation of Oracle client used by Perl is set up to request encrypted connections, then your Perl connection to the Oracle database will also be encrypted.