The basic security requirements of a secure e-commerce site are as follows:

1. Authentication: Are parties in the transaction who claims to be?
2. Privacy and confidentiality: Are transactions data protected? The consumer may want to make anonymous purchase. Are all non-essential traces of a transaction removed from the public network and all intermediary records eliminated?
3. Integrity: Checks that the message sent is complete that is they are not corrupted.
4. Non-repudiability: Ensures sender cannot deny sending message.
5. Availability: How can threats to the community and performance of the system be eliminated?
6. Besides the above mentioned points the concepts of Digital Certificates, Digital signatures, Public key infrastructure, certificate authorities etc. can be used.