| A New Provably Secure Authentication and Key Agreement Mechanism for SIP Using Certificateless Public-Key Cryptography Recent countries visiting this post |  |
 | 8 | United States |
 | 4 | China |
 | 4 |
| A New Provably Secure Authentication and Key Agreement Mechanism for SIP Using Certificateless Public-Key Cryptography Recent countries visiting this post | |
| 8 | United States |
| 4 | China |
| 4 |