ISO isn't a protocol it is an international standard:
The ISO 8583 specification has three parts:
Part 1: Messages, data elements, and code values
Part 2: Application and registration procedures for Institution Identification Codes (IIC)
Part 3: Maintenance procedures for the aforementioned messages, data elements and code values
When one stores credit card data you need to get PCI DSS certified:
Goals PCI DSS Requirements
Build and Maintain a Secure Network and Systems
1. Install and maintain network security controls
2. Apply secure configurations to all system components
Protect Account Data
3. Protect stored account data
4. Protect cardholder data with strong cryptography during transmission over open, public networks
Maintain a Vulnerability Management Program
5. Protect all systems and networks from malicious software
6. Develop and maintain secure systems and software
Implement Strong Access Control Measures
7. Restrict access to system components and cardholder data by business need to know
8. Identify users and authenticate access to system components
9. Restrict physical access to cardholder data
Regularly Monitor and Test Networks
10. Log and monitor all access to system components and cardholder data
11. Test security of systems and networks regularly
Maintain an Information Security Policy
12. Support information security with organizational policies and programs