A wireless communication system which employs cryptographic functions requiring random data input in a mobile wireless device includes provisions for securely adding randomness to the mobile wireless device. Such added randomness can be securely provided during synchronizing sessions with a device user's base computer via secure wired and/or wireless connections. The new random data can be obtained by software and/or hardware random number generators accessible to the user's base computer and/or from accessible secure external sources (e.g., a secure website source of random data).