SIDF

Technical Explanation

The SIDF is located inside the home network UDM (or co-located ARPF). It receives the encrypted SUCI from the visited AMF/AUSF, retrieves the operator's secret private key from a Hardware Security Module (HSM), and decrypts the SUCI to recover the plaintext SUPI for subscriber verification.

Key Functions

• Decrypts incoming SUCI tokens using the operator's private cryptographic key
• Hosted securely within home network UDM Hardware Security Modules (HSM)
• Ensures visited foreign networks never gain access to operator private keys