Casino software brands use some e-cash providers for making on-line money transactions, e.g., WagerLogic uses E-cash transaction processing software, developed by CryptoLogic.
These e-cash companies use 128-bit SSL digital encryption when transferring data via the Internet where each end-user is issued with a unique account number and chooses their own password, which they alone can access.
The same technology used by worldwide banks and the U.S. government to transmit data securely and confidentially between parties.
The e-cash provider also keeps a record of every transaction made. Should the need for a complete paper audit arise, the information is readily available.
So, if you fell that it is secure to buy at Amazon.com, then you should be comfortable depositing at a good casino.