Merge #19145: Add hash_type MUHASH for gettxoutsetinfo

e987ae5a554c9952812746c29f2766bacea4b727 test: Add test for deterministic UTXO set hash results (Fabian Jahr)
6ccc8fc067bf516cda7bc5d7d721945be5ac2003 test: Add test for gettxoutsetinfo RPC with MuHash (Fabian Jahr)
0d3b2f643d7da3202c0a0e757539208c4aa7c450 rpc: Add hash_type MUHASH to gettxoutsetinfo (Fabian Jahr)
2474645f3b15687e7f196b89eb935d6e6a98a9da refactor: Separate hash and stats calculation in coinstats (Fabian Jahr)
a1fcceac69097a8e6540a6fd8121a5d53022528f refactor: Improve encapsulation between MuHash3072 and Num3072 (Fabian Jahr)

Pull request description:

  This is another Pr in the series PRs for Coinstatsindex (see overview in #18000). This PR adds the `hash_type` option `muhash` to `gettxoutsetinfo` through which the user can calculate the serialized muhash of the utxo set. This PR does not use the index yet.

ACKs for top commit:
  Sjors:
    tACK e987ae5
  achow101:
    ACK e987ae5a554c9952812746c29f2766bacea4b727
  jonatack:
    Tested re-ACK e987ae5a554c9952812746c29f2766bacea4b727 per `git diff 3506d90 e987ae5`, reviewed diff, debug built, ran gettxoutsetinfo -signet and help on this branch vs master, at height 23127 both returned `hash_serialized_2` of `2b72d65f3b6efb2311f58374ea2b939abf49684d44f4bafda45faa3b5452a454` and this branch returned `muhash` of `c9f1ff12d345ccf9939c6bbf087e6f7399b6115adee1569287e9c5c43dbb475c`
  ryanofsky:
    Code review ACK e987ae5a554c9952812746c29f2766bacea4b727. Looks very good. I left one suggestion to simplify code, but feel free to ignore it here and maybe consider it for later since PR has already had a lot of review.

Tree-SHA512: 9a739ce375e73749fa69a467262b60d3e5314ef384e2d7150b3bbc8e4125cd9fd1db95306623bb9a632fcbaf5d9d2bf2f5cc43bf717d4ff5e2c9c4b52dd9296c

1 files changed, 25 insertions, 17 deletions

diff --git a/src/crypto/muhash.cpp b/src/crypto/muhash.cpp
index fbd14f9325..e5a0d4cb9c 100644
--- a/src/crypto/muhash.cpp
+++ b/src/crypto/muhash.cpp
@@ -17,7 +17,6 @@ namespace {
 using limb_t = Num3072::limb_t;
 using double_limb_t = Num3072::double_limb_t;
 constexpr int LIMB_SIZE = Num3072::LIMB_SIZE;
-constexpr int LIMBS = Num3072::LIMBS;
 /** 2^3072 - 1103717, the largest 3072-bit safe prime number, is used as the modulus. */
 constexpr limb_t MAX_PRIME_DIFF = 1103717;
 
@@ -123,7 +122,7 @@ inline void square_n_mul(Num3072& in_out, const int sq, const Num3072& mul)
 
 } // namespace
 
-/** Indicates wether d is larger than the modulus. */
+/** Indicates whether d is larger than the modulus. */
 bool Num3072::IsOverflow() const
 {
     if (this->limbs[0] <= std::numeric_limits<limb_t>::max() - MAX_PRIME_DIFF) return false;
@@ -276,18 +275,33 @@ void Num3072::Divide(const Num3072& a)
     if (this->IsOverflow()) this->FullReduce();
 }
 
-Num3072 MuHash3072::ToNum3072(Span<const unsigned char> in) {
-    Num3072 out{};
-    uint256 hashed_in = (CHashWriter(SER_DISK, 0) << in).GetSHA256();
-    unsigned char tmp[BYTE_SIZE];
-    ChaCha20(hashed_in.data(), hashed_in.size()).Keystream(tmp, BYTE_SIZE);
+Num3072::Num3072(const unsigned char (&data)[BYTE_SIZE]) {
+    for (int i = 0; i < LIMBS; ++i) {
+        if (sizeof(limb_t) == 4) {
+            this->limbs[i] = ReadLE32(data + 4 * i);
+        } else if (sizeof(limb_t) == 8) {
+            this->limbs[i] = ReadLE64(data + 8 * i);
+        }
+    }
+}
+
+void Num3072::ToBytes(unsigned char (&out)[BYTE_SIZE]) {
     for (int i = 0; i < LIMBS; ++i) {
         if (sizeof(limb_t) == 4) {
-            out.limbs[i] = ReadLE32(tmp + 4 * i);
+            WriteLE32(out + i * 4, this->limbs[i]);
         } else if (sizeof(limb_t) == 8) {
-            out.limbs[i] = ReadLE64(tmp + 8 * i);
+            WriteLE64(out + i * 8, this->limbs[i]);
         }
     }
+}
+
+Num3072 MuHash3072::ToNum3072(Span<const unsigned char> in) {
+    unsigned char tmp[Num3072::BYTE_SIZE];
+
+    uint256 hashed_in = (CHashWriter(SER_DISK, 0) << in).GetSHA256();
+    ChaCha20(hashed_in.data(), hashed_in.size()).Keystream(tmp, Num3072::BYTE_SIZE);
+    Num3072 out{tmp};
+
     return out;
 }
 
@@ -301,14 +315,8 @@ void MuHash3072::Finalize(uint256& out) noexcept
     m_numerator.Divide(m_denominator);
     m_denominator.SetToOne();  // Needed to keep the MuHash object valid
 
-    unsigned char data[384];
-    for (int i = 0; i < LIMBS; ++i) {
-        if (sizeof(limb_t) == 4) {
-            WriteLE32(data + i * 4, m_numerator.limbs[i]);
-        } else if (sizeof(limb_t) == 8) {
-            WriteLE64(data + i * 8, m_numerator.limbs[i]);
-        }
-    }
+    unsigned char data[Num3072::BYTE_SIZE];
+    m_numerator.ToBytes(data);
 
     out = (CHashWriter(SER_DISK, 0) << data).GetSHA256();
 }