1. A wireless device configured for authenticating a message, comprising: means for obtaining the message; means for generating a keystream; and means for computing, at the wireless device, a message authentication code using the keystream and a universal hash function wherein the universal hash function is computed using carryless multiplication, and wherein computing the universal hash function comprises: reversing a 32-bit word of the message; computing a first 64-bit word using carryless multiplication between the reversed 32-bit word of the message and a first 32-bit word of the keystream; computing a second 64-bit word using carryless multiplication between the reversed 32-bit word of the message and a second 32-bit word of the keystream; performing an exclusive-OR operation between a lowest 32-bit word of the first 64-bit word and a highest 32-bit word of the second 64-bit word to obtain a first 32-bit variable; and performing an exclusive-OR operation between a second 32-bit variable and the first 32-bit variable.