This is one of the forms of tzeruf, letter exchange, that was taught to us by Moshe Rabbeinu like is explained in the opening words of Sefer HaMalchut Chochmat HaTzeruf by Rabbi David HaLevi and in Kuntress Sheirit Yosef on Sefer Ma'ayan HaChochmah by Rabbi Yosef Bar Shimshon Rafoel, Sha'ar 1:2.
Each form of tzeruf transformation indicates a different level of understanding and a step down from the source letters. The greater the transformation, the greater the descent. This is discussed in the opening chapters of the second section of the Tanya, Sha'ar HaYichud v'HaEmunah.
In this particular case, the type of tzeruf used is Semichah, which means in close proximity or touching. There is not much of a transformation. It contains the same number of letters and is in the same order.
The writing on the back of the klaf is the concept of going from front to back as it appears in the Torah, like the idea of how HaShem sustains the Sitra Achra begrudgingly, by tossing sustenance to it over His shoulder, to His back so to speak.
The letters for this type of transformation are the next letters in the order of the Alef-Beit from the source phrase. For example, the letter ב is somech to the letter א. The letter ל is somech to the letter כ.
So in this case, the unadulterated, source phrase is: יהוה אלהינו יהוה.
The Semicha transformation of that phrase is: כוזו במוכסז כוזו.