In one aspect, a device includes an encoder configured to receive a speech sample and generate an encoded voice packet from the speech sample, the encoded voice packet having a packet size and a plurality of bytes. The device also includes an encryption unit configured to receive a voice block and generate an encrypted voice block, the voice block having a block size, wherein the packet size is not divisible by the block size and yields a remainder. The device further includes a packet block manager configured to divide the encoded voice packet into a plurality of the voice blocks and provide the plurality of the voice blocks to the encryption unit, the packet block manager further configured to create a remainder voice block including remainder bytes of the encoded voice packet and additional bytes from the encrypted voice block and provide the remainder voice block to the encryption unit.