docs(tt_um_litneet64_ro_puf): sync diagram fix and readme details

projects/tt_um_litneet64_ro_puf/docs/info.md

@@ -9,12 +9,12 @@ You can also include images in this folder and reference them in the markdown. E
 
 ## How it works
 
-A physical unclonable function (PUF) is a hardware primitive that maps an input (called a challenge) to an output (called a response) in a similar fashion to a hash function. The goal of a PUF can be many: uniquely identifying an integrated circuit (IC) from another while still keeping deterministic outputs for the same IC, using a set of challenge-response pairs (CRP); generating random-enough nonces; or even authenticating an IC (stronger version of identification). In order to evaluate its performance for those goals, relevant metrics such as **uniqueness**, **reliability**, **uniformity** and **entropy** of CRPs over many PUF ICs are commonly employed. The PUF implementation for this project uses many identical, 7-inverter ring oscillators (RO) which introduce randomness or variation in their operating frequencies at the time of the fabrication process itself. 
+A physical unclonable function (PUF) is a hardware security primitive that maps an input (called a challenge) to an output (called a response) in a similar fashion to a hash function. The goal of a PUF can be many: uniquely identifying an integrated circuit (IC) from another while still keeping deterministic outputs for the same IC, using a set of challenge-response pairs (CRP); generating random-enough nonces; or even authenticating an IC (stronger version of identification). In order to evaluate its performance for those goals, relevant metrics such as **uniqueness**, **reliability**, **uniformity** and **entropy** of CRPs over many PUF ICs are commonly employed. The PUF implementation for this project uses many identical, 7-inverter ring oscillators (RO) which introduce randomness or variation in their operating frequencies at the time of the fabrication process itself. 
 
 ![](ro_puf_1bit_block.png)
 
 In this case, an 8-bit parallel architecture for each bit of a CR
-P is adopted. The 8-bit challenge is shared along 8 independent blocks in order to derive only 1-bit of the response per block. One PUF block contains 32 ROs, where one RO is selected between the top half of the ROs over a challenge-dependent 16-bit mux, while other RO is selected from the remaining bottom half over the second chall-dependent 16-bit mux. Then, both muxes connect directly to 1 counter of its own. Both of the counters then race each other until a given threshold (65535 in this case) is reached, and an arbiter module that's connected to both counters declares the winner in a 1-bit response.
+P is adopted. The 8-bit challenge is shared along 8 independent blocks in order to derive only 1-bit of the response per block. One PUF block contains 32 ROs, where one RO is selected between the top half of the ROs over a challenge-dependent (4 MSB) 16-bit mux, while other RO is selected from the remaining bottom half over the second chall-dependent (4 LSB) 16-bit mux. Then, both muxes connect directly to 1 counter of its own. Both of the counters then race each other until a given threshold (65535 in this case) is reached, and an arbiter module that's connected to both counters declares the winner in a 1-bit response.
 
 ![](ro_puf_8bit.png)