Three major applications for Java Card technology

1. EMV (Europay, Mastercard, and Visa): 

- Primary use: Payment cards (credit and debit cards) 

- Features: 

- Secure storage of cardholder data 

- Cryptographic processing for transaction authentication 

- Support for offline and online transactions 

- Benefits: 

- Enhanced security over magnetic stripe cards 

- Flexibility to update card applications 

- Global interoperability 

2. SecurID (RSA SecurID): 

- Primary use: Two-factor authentication tokens 

- Features: - Generation of one-time passwords (OTPs) 

- Secure storage of seed values 

- Time-based or event-based OTP generation 

- Benefits: - Strong authentication for access to sensitive systems 

- Resistant to replay attacks 

- Can be implemented as hardware tokens or software tokens 

3. SIM (Subscriber Identity Module) cards for Telecom: 

- Primary use: Mobile network authentication and subscriber identity 

- Features: - Secure storage of subscriber information (IMSI, encryption keys) 

- Support for over-the-air (OTA) updates 

- Ability to run multiple applets (e.g., for mobile banking, NFC payments) 

- Benefits: - Secure authentication to mobile networks 

- Portability of subscriber identity between devices 

- Platform for value-added services 

These applications leverage Java Card's key advantages: 

1. Security: Java Card provides a secure execution environment for sensitive operations. 

2. Flexibility: The ability to update and add applications post-issuance. 

3. Interoperability: Java Card applets can run on different hardware, promoting standardization. 

4. Multi-application support: A single card can host multiple secure applications. 

For each of these applications, Java Card technology allows for secure, updatable, and interoperable implementations, which are crucial in the fields of finance, authentication, and telecommunications.