Cipher Mail
Compose a mail by pressing [X] in the mail screen, and send it to yourself. Type "Cipher" in the subject, then type the code in the body of the email. Send the email, and exit back to the main screen (Map screen). If entered correctly, it should give you a card.
SIXGAME-O - D.Energy SubCard
NGYNGIWCUS - GhostPulse2 B. Card
AURIEFRUTS - Recovery 50 B. Card
PREOBCOPB - SearchEye SubCard
LAREBARAON - TimeBomb1 B. Card
NROSIMAMSTU - Unlocker SubCard