diff --git a/miden-tx/src/testing/mock_chain/mod.rs b/miden-tx/src/testing/mock_chain/mod.rs
index 8dd7b3796..5c63d2aae 100644
--- a/miden-tx/src/testing/mock_chain/mod.rs
+++ b/miden-tx/src/testing/mock_chain/mod.rs
@@ -653,7 +653,9 @@ impl MockChain {
     /// This will also make all the objects currently pending available for use.
     /// If `block_num` is `Some(number)`, blocks will be generated up to `number`.
     pub fn seal_block(&mut self, block_num: Option<u32>) -> Block {
-        let next_block_num = self.blocks.last().map_or(0, |b| b.header().block_num().child());
+        let next_block_num =
+            self.blocks.last().map_or(0, |b| b.header().block_num().child().as_u32());
+
         let target_block_num = block_num.unwrap_or(next_block_num);
 
         if target_block_num < next_block_num {
diff --git a/objects/src/block/block_number.rs b/objects/src/block/block_number.rs
index 5e4bfa862..51efc33de 100644
--- a/objects/src/block/block_number.rs
+++ b/objects/src/block/block_number.rs
@@ -22,14 +22,17 @@ impl BlockNumber {
     /// exponent.
     pub const EPOCH_LENGTH_EXPONENT: u8 = 16;
 
+    /// Genesis BlockNumber
+    pub const GENESIS: Self = Self(0);
+
     /// Returns the previous block number
-    pub fn parent(&self) -> u32 {
-        self.checked_sub(1).expect("Cannot go below Genesis block!").0
+    pub fn parent(self) -> Option<BlockNumber> {
+        self.checked_sub(1)
     }
 
     /// Returns the next block number
-    pub fn child(&mut self) -> u32 {
-        self.0 + 1
+    pub fn child(self) -> BlockNumber {
+        self + 1
     }
 
     /// Creates the [`BlockNumber`] corresponding to the epoch block for the provided `epoch`.
@@ -62,7 +65,7 @@ impl BlockNumber {
         self.0 as usize
     }
 
-    /// Checked integer subtraction. Computes `self - rhs`, returning `None` if overflow occurred.
+    /// Checked integer subtraction. Computes `self - rhs`, returning `None` if underflow occurred.
     pub fn checked_sub(&self, rhs: u32) -> Option<Self> {
         self.0.checked_sub(rhs).map(Self)
     }
diff --git a/objects/src/errors.rs b/objects/src/errors.rs
index d93ee04d3..9b5413a06 100644
--- a/objects/src/errors.rs
+++ b/objects/src/errors.rs
@@ -356,7 +356,7 @@ pub enum TransactionInputError {
     #[error("block in which input note with id {0} was created is not in chain mmr")]
     InputNoteBlockNotInChainMmr(NoteId),
     #[error("input note with id {0} was not created in block {1}")]
-    InputNoteNotInBlock(NoteId, u32),
+    InputNoteNotInBlock(NoteId, BlockNumber),
     #[error("account ID computed from seed is invalid")]
     InvalidAccountIdSeed(#[source] AccountIdError),
     #[error(
diff --git a/objects/src/transaction/inputs.rs b/objects/src/transaction/inputs.rs
index 8ae09ebe5..b011cbc10 100644
--- a/objects/src/transaction/inputs.rs
+++ b/objects/src/transaction/inputs.rs
@@ -402,10 +402,7 @@ fn validate_is_in_block(
         .note_path()
         .verify(note_index, note_hash, &block_header.note_root())
         .map_err(|_| {
-            TransactionInputError::InputNoteNotInBlock(
-                note.id(),
-                proof.location().block_num().as_u32(),
-            )
+            TransactionInputError::InputNoteNotInBlock(note.id(), proof.location().block_num())
         })
 }