From 378f13d94881a8fcb25323ee4f530c5b5e1ce4e3 Mon Sep 17 00:00:00 2001
From: Bartosz Nowak <bartekn337@gmail.com>
Date: Sat, 6 Jan 2024 19:27:49 +0100
Subject: [PATCH] impl refactor

---
 src/proof_of_work/proof_of_work.cairo         | 56 +++++--------------
 src/proof_of_work/tests.cairo                 |  2 +-
 .../tests/test_proof_of_work.cairo            | 10 ++++
 3 files changed, 25 insertions(+), 43 deletions(-)

diff --git a/src/proof_of_work/proof_of_work.cairo b/src/proof_of_work/proof_of_work.cairo
index 0b3505be4..a0a8b550b 100644
--- a/src/proof_of_work/proof_of_work.cairo
+++ b/src/proof_of_work/proof_of_work.cairo
@@ -1,17 +1,13 @@
-use core::array::SpanTrait;
-use core::array::ArrayTrait;
-use cairo_verifier::common::flip_endianness::FlipEndiannessTrait;
-use core::debug::PrintTrait;
 use cairo_verifier::{
-    common::{blake2s_u8::blake2s, array_append::ArrayAppendTrait, math::pow},
+    common::{
+        flip_endianness::FlipEndiannessTrait, array_print::{SpanPrintTrait, ArrayPrintTrait},
+        blake2s_u8::blake2s, array_append::ArrayAppendTrait, math::pow,
+    },
     channel::channel::{Channel, ChannelTrait},
     proof_of_work::config::{ProofOfWorkConfig, BYTE_UPPER_BOUND, WORD_UPPER_BOUND}
 };
-use cairo_verifier::common::array_print::{SpanPrintTrait, ArrayPrintTrait};
 
-const POW_2_12: u256 = 79228162514264337593543950336;
-const POW_2_4: u256 = 4294967296;
-const POW_2_3: u256 = 16777216;
+const MAGIC: u64 = 0x0123456789abcded;
 
 #[derive(Drop, Copy)]
 struct ProofOfWorkUnsentCommitment {
@@ -31,45 +27,21 @@ fn verify_proof_of_work(digest: u256, n_bits: u8, nonce: u64) {
     //      8 bytes          || 32 bytes || 1 byte
     // Total of 0x29 = 41 bytes.
 
-    // let init_hash_value: u256 = 0x0123456789abcded000000000000000000000000000000000000000000000000
-    //     // digest >> 12 -> digest << 4 -> nbits << 3
-    //     + digest / POW_2_12 * POW_2_4 + n_bits.into() * POW_2_3;
-
     let mut init_hash_data = ArrayTrait::<u8>::new();
-    init_hash_data.append_big_endian(u256{low: 0xD7CA1D48A19D8FF802A71D94169DE383, high: 0x0123456789ABCDED1C5A5F4381DF1F5C});
-    init_hash_data.append_big_endian(u256{low: 0x00000000000000000000000000000000, high: 0x82621FDC5514A10A1400000000000000});
-    let span = init_hash_data.span().slice(0,0x29);
-    let mut arr = ArrayTrait::<u8>::new();
-    let mut i:u32 = 0;
-    loop {
-        if i == span.len() {
-            break;
-        }
-
-        arr.append(*span.at(i));
-        i+=1;
-    };
-    let init_hash = blake2s(arr).flip_endianness();
+    init_hash_data.append_big_endian(MAGIC);
+    init_hash_data.append_big_endian(digest);
+    init_hash_data.append(n_bits);
+    let init_hash = blake2s(init_hash_data).flip_endianness();
 
-    // // Compute Hash(init_hash || nonce   )
-    // //              32 bytes  || 8 bytes
-    // // Total of 0x28 = 40 bytes.
+    // Compute Hash(init_hash || nonce   )
+    //              32 bytes  || 8 bytes
+    // Total of 0x28 = 40 bytes.
 
     let mut hash_data = ArrayTrait::<u8>::new();
     hash_data.append_big_endian(init_hash);
-    hash_data.append_big_endian(u256{low: 0x00000000000000000000000000000000, high: 0x000000000001683b0000000000000000});
-    let span = hash_data.span().slice(0,0x28);
-    let mut arr = ArrayTrait::<u8>::new();
-    let mut i:u32 = 0;
-    loop {
-        if i == span.len() {
-            break;
-        }
+    hash_data.append_big_endian(nonce);
+    let hash = blake2s(hash_data).flip_endianness();
 
-        arr.append(*span.at(i));
-        i+=1;
-    };
-    let hash = blake2s(arr).flip_endianness();
     let work_limit = pow(2, 128 - n_bits.into());
     assert(
         Into::<u128, u256>::into(hash.high) < Into::<felt252, u256>::into(work_limit),
diff --git a/src/proof_of_work/tests.cairo b/src/proof_of_work/tests.cairo
index 1164558f8..57bb36e70 100644
--- a/src/proof_of_work/tests.cairo
+++ b/src/proof_of_work/tests.cairo
@@ -1 +1 @@
-mod test_proof_of_work;
\ No newline at end of file
+mod test_proof_of_work;
diff --git a/src/proof_of_work/tests/test_proof_of_work.cairo b/src/proof_of_work/tests/test_proof_of_work.cairo
index 0f1401677..78716fabc 100644
--- a/src/proof_of_work/tests/test_proof_of_work.cairo
+++ b/src/proof_of_work/tests/test_proof_of_work.cairo
@@ -8,3 +8,13 @@ fn test_verify_proof_of_work_0() {
     let n_bits: u8 = 20;
     verify_proof_of_work(digest, n_bits, nonce);
 }
+
+#[test]
+#[should_panic]
+#[available_gas(9999999999)]
+fn test_verify_proof_of_work_1() {
+    let digest: u256 = 0x1c5a5f4381df1f5cd7ca1d48a19d8ff802a71d94169de38382621fdc5514a10a;
+    let nonce: u64 = 0x1683b + 1;
+    let n_bits: u8 = 20;
+    verify_proof_of_work(digest, n_bits, nonce);
+}