feat: Set transaction expiry block delta (#897)

* feat: Set transaction recency conditions

* Correctly build stack outputs for verifier

* Format correctly

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ## 0.6.0 (TBD)
 
+- Implemented kernel procedure to set transaction expiration block delta (#897).
 - Created a proving service that receives `TransactionWitness` and returns the proof using gRPC (#881).
 - Made note scripts public (#880).
 - Implemented serialization for `TransactionWitness`, `ChainMmr`, `TransactionInputs` and `TransactionArgs` (#888).

miden-lib/asm/kernels/transaction/api.masm

@@ -893,6 +893,32 @@ export.end_foreign_context
     dropw
 end
 
+#! Updates the transaction expiration time delta.
+#! Once set, the delta can be decreased but not increased. 
+#!
+#! The input block height delta is added to the reference block in order to output an upper limit
+#! up until which the transaction will be considered valid (not expired).
+#!
+#! Inputs: [block_height_delta, ...]
+#! Output: [...]
+#!
+#! Where:
+#! - block_height_delta is the desired expiration time delta (1 to 0xFFFF).
+export.update_expiration_block_num
+    exec.tx::update_expiration_block_num
+end
+
+#! Gets the transaction expiration delta.
+#!
+#! Inputs: [...]
+#! Output: [block_height_delta, ...]
+#!
+#! Where:
+#! - block_height_delta is the stored expiration time delta (1 to 0xFFFF).
+export.get_expiration_delta
+    exec.tx::get_expiration_delta
+end
+
 #! Executes a kernel procedure specified by its offset.
 #!
 #! Inputs: [procedure_offset, <procedure_inputs>, <pad>]

miden-lib/asm/kernels/transaction/lib/epilogue.masm

@@ -3,6 +3,7 @@ use.kernel::asset_vault
 use.kernel::constants
 use.kernel::memory
 use.kernel::note
+use.kernel::tx
 
 use.std::crypto::hashes::native
 
@@ -224,7 +225,7 @@ end
 #! - asserts that the input and output vault roots are equal
 #!
 #! Stack: []
-#! Output: [OUTPUT_NOTES_COMMITMENT, FINAL_ACCOUNT_HASH]
+#! Output: [OUTPUT_NOTES_COMMITMENT, FINAL_ACCOUNT_HASH, tx_expiration_block_num]
 #!
 #! - OUTPUT_NOTES_COMMITMENT is the commitment of the output notes
 #! - FINAL_ACCOUNT_HASH is the final account hash
@@ -308,4 +309,9 @@ export.finalize_transaction
     # assert no net creation or destruction of assets over the transaction
     exec.memory::get_input_vault_root exec.memory::get_output_vault_root assert_eqw.err=ERR_EPILOGUE_ASSETS_DONT_ADD_UP
     # => [OUTPUT_NOTES_COMMITMENT, FINAL_ACCOUNT_HASH]
+
+    swapdw
+    exec.memory::get_expiration_block_num
+    swap drop swapdw
+    # => [OUTPUT_NOTES_COMMITMENT, FINAL_ACCOUNT_HASH, tx_expiration_block_num]
 end

miden-lib/asm/kernels/transaction/lib/memory.masm

@@ -32,6 +32,9 @@ const.CURRENT_ACCOUNT_DATA_PTR=5
 # The memory address at which the native account's new code commitment is stored.
 const.NEW_CODE_ROOT_PTR=6
 
+# The memory address at which the absolute expiration block number is stored.
+const.TX_EXPIRATION_BLOCK_NUM_PTR=7
+
 # GLOBAL INPUTS
 # -------------------------------------------------------------------------------------------------
 
@@ -829,6 +832,22 @@ export.set_new_acct_code_commitment
     mem_storew
 end
 
+#! Sets the transaction expiration block number.
+#!
+#! Inputs: [tx_expiration_block_num, ...]
+#! Output: [...]
+export.set_expiration_block_num
+    push.TX_EXPIRATION_BLOCK_NUM_PTR mem_store
+end
+
+#! Gets the transaction expiration block number.
+#!
+#! Inputs: []
+#! Output: [tx_expiration_block_num]
+export.get_expiration_block_num
+    push.TX_EXPIRATION_BLOCK_NUM_PTR mem_load
+end
+
 #! Returns the number of procedures contained in the account code.
 #!
 #! Stack: []

miden-lib/asm/kernels/transaction/lib/prologue.masm

@@ -9,6 +9,12 @@ use.kernel::constants
 use.kernel::memory
 use.kernel::utils
 
+# CONSTS
+# =================================================================================================
+
+# Max U32 value, used for initializing the expiration block number
+const.MAX_BLOCK_NUM=0xFFFFFFFF
+
 # ERRORS
 # =================================================================================================
 
@@ -1233,4 +1239,6 @@ export.prepare_transaction
     exec.process_input_notes_data
     exec.process_tx_script_root
     # => []
+
+    push.MAX_BLOCK_NUM exec.memory::set_expiration_block_num
 end

miden-lib/asm/kernels/transaction/lib/tx.masm

@@ -15,6 +15,9 @@ const.ENCRYPTED_NOTE=3  # 0b11
 # Two raised to the power of 38 (2^38), used for shifting the note type value
 const.TWO_POW_38=274877906944
 
+# Max value for U16, used as the upper limit for expiration block delta
+const.EXPIRY_UPPER_LIMIT=0xFFFF+1
+
 # ERRORS
 # =================================================================================================
 
@@ -61,6 +64,9 @@ const.ERR_NON_FUNGIBLE_ASSET_ALREADY_EXISTS=0x00020051
 # Note idx must be within [0, num_of_notes]
 const.ERR_INVALID_NOTE_IDX=0x00020052
 
+# Input transaction expiration block delta is not within 0x1 and 0xFFFF.
+const.ERR_INVALID_TX_EXPIRATION_DELTA=0x00020055
+
 # EVENTS
 # =================================================================================================
 
@@ -73,7 +79,7 @@ const.NOTE_AFTER_CREATED_EVENT=131084
 const.NOTE_BEFORE_ADD_ASSET_EVENT=131085
 # Event emitted after an ASSET is added to a note
 const.NOTE_AFTER_ADD_ASSET_EVENT=131086
-
+ 
 #! Returns the block hash of the reference block to memory.
 #!
 #! Stack: []
@@ -178,6 +184,53 @@ proc.add_non_fungible_asset_to_note
     # => [note_ptr, note_idx]
 end
 
+#! Updates the transaction expiration block number.
+#!
+#! The input block_height_delta is added to the block reference number in order to output an upper
+#! limit at which the transaction will be considered valid (not expired).
+#! This value can be later decreased, but not increased. 
+#!
+#! Inputs: [block_height_delta, ...]
+#! Output: [...]
+#!
+#! Where:
+#! - block_height_delta is the desired expiration time delta (1 to 0xFFFF).
+export.update_expiration_block_num
+    # Ensure block_height_delta is between 1 and 0xFFFF (inclusive)
+    dup neq.0 assert.err=ERR_INVALID_TX_EXPIRATION_DELTA
+    dup push.EXPIRY_UPPER_LIMIT lt assert.err=ERR_INVALID_TX_EXPIRATION_DELTA
+    # => [block_height_delta]
+
+    exec.get_block_number add
+    # => [absolute_expiration_num]
+
+    # Load the current stored delta from memory
+    dup exec.memory::get_expiration_block_num  
+    # => [stored_expiration_block_num, absolute_expiration_num, absolute_expiration_num]
+
+    # Check if block_height_delta is greater
+    u32lt
+    if.true
+        # Set new expiration delta
+        exec.memory::set_expiration_block_num 
+    else
+        drop                           
+    end
+end
+
+#! Gets the transaction expiration delta.
+#!
+#! Inputs: [...]
+#! Output: [block_height_delta, ...]
+#!
+#! Where:
+#! - block_height_delta is the stored expiration time delta (1 to 0xFFFF).
+export.get_expiration_delta
+    exec.memory::get_expiration_block_num exec.get_block_number
+    sub
+end
+
+
 #! Adds a fungible asset to a note. If the note already holds an asset issued by the
 #! same faucet id the two quantities are summed up and the new quantity is stored at the
 #! old position in the note. In the other case, the asset is stored at the next available

miden-lib/asm/miden/kernel_proc_offsets.masm

@@ -38,6 +38,8 @@ const.GET_BLOCK_HASH_OFFSET=26
 const.GET_BLOCK_NUMBER_OFFSET=27
 const.START_FOREIGN_CONTEXT_OFFSET=28
 const.END_FOREIGN_CONTEXT_OFFSET=29
+const.UPDATE_EXPIRATION_BLOCK_NUM_OFFSET=30
+const.GET_EXPIRATION_DELTA_OFFSET=31
 
 # ACCESSORS
 # -------------------------------------------------------------------------------------------------
@@ -105,7 +107,7 @@ end
 #! Returns an offset of the `get_account_item` kernel procedure.
 #!
 #! Stack: []
-#! Output: [proc_offset]
+#! Output: [proc_offset] 
 #!
 #! Where:
 #! - proc_offset is the offset of the `get_account_item` kernel procedure required to get the 
@@ -258,6 +260,30 @@ export.get_block_number_offset
     push.GET_BLOCK_NUMBER_OFFSET
 end
 
+#! Returns an offset of the `update_expiration_block_num` kernel procedure.
+#!
+#! Stack: []
+#! Output: [proc_offset]
+#!
+#! Where:
+#! - proc_offset is the offset of the `set_tx_expiration_delta` kernel procedure required to get the 
+#! address where this procedure is stored.
+export.update_expiration_block_num_offset
+    push.UPDATE_EXPIRATION_BLOCK_NUM_OFFSET
+end
+
+#! Returns an offset of the `get_expiration_delta` kernel procedure.
+#!
+#! Stack: []
+#! Output: [proc_offset]
+#!
+#! Where:
+#! - proc_offset is the offset of the `set_tx_expiration_delta` kernel procedure required to get the 
+#! address where this procedure is stored.
+export.get_expiration_block_delta_offset
+    push.GET_EXPIRATION_DELTA_OFFSET
+end
+
 #! Returns an offset of the `get_block_hash` kernel procedure.
 #!
 #! Stack: []

miden-lib/src/transaction/memory.rs

@@ -14,7 +14,7 @@ pub type StorageSlot = u8;
 //
 // | Section           | Start address |  End address |
 // | -------------     | :------------:| :-----------:|
-// | Bookkeeping       | 0             | 6            |
+// | Bookkeeping       | 0             | 7            |
 // | Global inputs     | 100           | 105          |
 // | Block header      | 200           | 208          |
 // | Chain MMR         | 300           | 332?         |
@@ -73,6 +73,9 @@ pub const CURRENT_ACCOUNT_DATA_PTR: MemoryAddress = 5;
 /// The memory address at which the native account's new code commitment is stored.
 pub const NEW_CODE_ROOT_PTR: MemoryAddress = 6;
 
+/// The memory address at which the transaction expiration block number is stored.
+pub const TX_EXPIRATION_BLOCK_NUM_PTR: MemoryAddress = 7;
+
 // GLOBAL INPUTS
 // ------------------------------------------------------------------------------------------------