1. A method comprising: combining, by a processing device of a computer with a memory executing a pseudo-random number mixer, a first pseudo-random number received from a first source with a second pseudo-random number received from a second source non-linearly to generate a third pseudo-random number, the combining comprising: performing multiplication based on the first pseudo-random number and the second pseudo-random number; performing a modulo operation on a result of the multiplication, wherein the modulo operation has an operand that is based on a bit size of the first pseudo-random number, wherein the first pseudo-random number, the second pseudo-random number, and the third-pseudo-random number are a same bit size; and outputting a result of the modulo operation as the third pseudo-random number; and applying, by the processing device, the third pseudo-random number in a cipher operation.