diff --git a/include/bitcoin/system/chain/block.hpp b/include/bitcoin/system/chain/block.hpp
index 6db8d06e2f..3d1869dad2 100644
--- a/include/bitcoin/system/chain/block.hpp
+++ b/include/bitcoin/system/chain/block.hpp
@@ -112,6 +112,9 @@ class BC_API block
     /// Reference used to avoid copy, sets cache if not set (not thread safe).
     const hash_digest& get_hash() const NOEXCEPT;
 
+    /// Optimized hash derivations using wire serialization of same block.
+    void set_hashes(const data_chunk& data) NOEXCEPT;
+
     /// Set/get memory allocation.
     void set_allocation(size_t allocation) const NOEXCEPT;
     size_t get_allocation() const NOEXCEPT;
diff --git a/include/bitcoin/system/chain/transaction.hpp b/include/bitcoin/system/chain/transaction.hpp
index 9d9f6f5fb3..ec1b1fb055 100644
--- a/include/bitcoin/system/chain/transaction.hpp
+++ b/include/bitcoin/system/chain/transaction.hpp
@@ -45,9 +45,14 @@ class BC_API transaction
     typedef std::shared_ptr<const transaction> cptr;
     typedef input_cptrs::const_iterator input_iterator;
 
+    /// Not genesis and at least 100 blocks deep.
     static bool is_coinbase_mature(size_t coinbase_height,
         size_t height) NOEXCEPT;
 
+    /// Optimized non-witness hash derivation using witness-serialized tx.
+    static hash_digest desegregated_hash(size_t witnessed,
+        size_t unwitnessed, const uint8_t* data) NOEXCEPT;
+
     /// Constructors.
     /// -----------------------------------------------------------------------
 
diff --git a/src/chain/block.cpp b/src/chain/block.cpp
index 33d5d84319..1bff491f9b 100644
--- a/src/chain/block.cpp
+++ b/src/chain/block.cpp
@@ -263,6 +263,44 @@ const hash_digest& block::get_hash() const NOEXCEPT
     return header_->get_hash();
 }
 
+void block::set_hashes(const data_chunk& data) NOEXCEPT
+{
+    constexpr auto header_size = chain::header::serialized_size();
+
+    // Cache header hash.
+    header_->set_hash(bitcoin_hash(header_size, data.data()));
+
+    // Skip transaction count, guarded by preceding successful block construct.
+    auto start = std::next(data.data(), header_size);
+    std::advance(start, size_variable(*start));
+
+    // Cache transaction hashes.
+    auto coinbase = true;
+    for (const auto& tx: *txs_)
+    {
+        const auto witness_size = tx->serialized_size(true);
+
+        // If !witness then wire txs cannot have been segregated.
+        if (tx->is_segregated())
+        {
+            const auto nominal_size = tx->serialized_size(false);
+
+            tx->set_nominal_hash(transaction::desegregated_hash(
+                witness_size, nominal_size, start));
+
+            if (!coinbase)
+                tx->set_witness_hash(bitcoin_hash(witness_size, start));
+        }
+        else
+        {
+            tx->set_nominal_hash(bitcoin_hash(witness_size, start));
+        }
+
+        coinbase = false;
+        std::advance(start, witness_size);
+    }
+}
+
 // static/private
 block::sizes block::serialized_size(
     const chain::transaction_cptrs& txs) NOEXCEPT
diff --git a/src/chain/transaction.cpp b/src/chain/transaction.cpp
index c270817f12..488531738a 100644
--- a/src/chain/transaction.cpp
+++ b/src/chain/transaction.cpp
@@ -442,6 +442,27 @@ hash_digest transaction::hash(bool witness) const NOEXCEPT
     return digest;
 }
 
+// static
+hash_digest transaction::desegregated_hash(size_t witnessed,
+    size_t unwitnessed, const uint8_t* data) NOEXCEPT
+{
+    if (is_null(data))
+        return null_hash;
+
+    constexpr auto preamble = sizeof(uint32_t) + two * sizeof(uint8_t);
+    const auto puts = floored_subtract(unwitnessed, two * sizeof(uint32_t));
+    const auto locktime = floored_subtract(witnessed, sizeof(uint32_t));
+
+    hash_digest digest{};
+    stream::out::fast stream{ digest };
+    hash::sha256x2::fast sink{ stream };
+    sink.write_bytes(data, sizeof(uint32_t));
+    sink.write_bytes(std::next(data, preamble), puts);
+    sink.write_bytes(std::next(data, locktime), sizeof(uint32_t));
+    sink.flush();
+    return digest;
+}
+
 // Methods.
 // ----------------------------------------------------------------------------