diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md
index 4ba4a91bf..2bd7f23b7 100644
--- a/specs/core/0_beacon-chain.md
+++ b/specs/core/0_beacon-chain.md
@@ -799,6 +799,9 @@ def compute_domain(domain_type: DomainType, fork_version: Version=Version()) ->
 
 ```python
 def compute_signing_root(ssz_object: SSZObject, domain: Domain) -> Root:
+    """
+    Return the signing root of an object by calculating the root of the object-domain tree.
+    """
     domain_wrapped_object = SigningRoot(
         object_root=hash_tree_root(ssz_object),
         domain=domain,
@@ -959,11 +962,11 @@ def get_total_active_balance(state: BeaconState) -> Gwei:
 #### `get_domain`
 
 ```python
-def get_domain(state: BeaconState, domain_type: DomainType, message_epoch: Epoch=None) -> Domain:
+def get_domain(state: BeaconState, domain_type: DomainType, epoch: Epoch=None) -> Domain:
     """
     Return the signature domain (fork version concatenated with domain type) of a message.
     """
-    epoch = get_current_epoch(state) if message_epoch is None else message_epoch
+    epoch = get_current_epoch(state) if epoch is None else epoch
     fork_version = state.fork.previous_version if epoch < state.fork.epoch else state.fork.current_version
     return compute_domain(domain_type, fork_version)
 ```
diff --git a/specs/core/1_custody-game.md b/specs/core/1_custody-game.md
index 23f9f3f4d..4df9c3352 100644
--- a/specs/core/1_custody-game.md
+++ b/specs/core/1_custody-game.md
@@ -482,10 +482,8 @@ def process_early_derived_secret_reveal(state: BeaconState, reveal: EarlyDerived
     pubkeys = [revealed_validator.pubkey, masker.pubkey]
 
     domain = get_domain(state, DOMAIN_RANDAO, reveal.epoch)
-    messages = [compute_signing_root(message, domain)
-                for message in [hash_tree_root(reveal.epoch), reveal.mask]]
-
-    assert bls.AggregateVerify(pubkeys, messages, reveal.reveal)
+    signing_roots = [compute_signing_root(root, domain) for root in [hash_tree_root(reveal.epoch), reveal.mask]]
+    assert bls.AggregateVerify(pubkeys, signing_roots, reveal.reveal)
 
     if reveal.epoch >= get_current_epoch(state) + CUSTODY_PERIOD_TO_RANDAO_PADDING:
         # Full slashing when the secret was revealed so early it may be a valid custody
diff --git a/test_libs/pyspec/eth2spec/test/helpers/attestations.py b/test_libs/pyspec/eth2spec/test/helpers/attestations.py
index 52479fd75..cb3e86320 100644
--- a/test_libs/pyspec/eth2spec/test/helpers/attestations.py
+++ b/test_libs/pyspec/eth2spec/test/helpers/attestations.py
@@ -97,8 +97,8 @@ def sign_attestation(spec, state, attestation):
 
 def get_attestation_signature(spec, state, attestation_data, privkey):
     domain = spec.get_domain(state, spec.DOMAIN_BEACON_ATTESTER, attestation_data.target.epoch)
-    message = spec.compute_signing_root(attestation_data, domain)
-    return bls.Sign(privkey, message)
+    signing_root = spec.compute_signing_root(attestation_data, domain)
+    return bls.Sign(privkey, signing_root)
 
 
 def fill_aggregate_attestation(spec, state, attestation, signed=False):
diff --git a/test_libs/pyspec/eth2spec/test/helpers/block.py b/test_libs/pyspec/eth2spec/test/helpers/block.py
index 9b2cc5d03..dda03cbf1 100644
--- a/test_libs/pyspec/eth2spec/test/helpers/block.py
+++ b/test_libs/pyspec/eth2spec/test/helpers/block.py
@@ -30,8 +30,8 @@ def apply_randao_reveal(spec, state, block, proposer_index=None):
     privkey = privkeys[proposer_index]
 
     domain = spec.get_domain(state, spec.DOMAIN_RANDAO, spec.compute_epoch_at_slot(block.slot))
-    message = spec.compute_signing_root(spec.compute_epoch_at_slot(block.slot), domain)
-    block.body.randao_reveal = bls.Sign(privkey, message)
+    signing_root = spec.compute_signing_root(spec.compute_epoch_at_slot(block.slot), domain)
+    block.body.randao_reveal = bls.Sign(privkey, signing_root)
 
 
 # Fully ignore the function if BLS is off, beacon-proposer index calculation is slow.
@@ -42,9 +42,9 @@ def apply_sig(spec, state, signed_block, proposer_index=None):
     proposer_index = get_proposer_index_maybe(spec, state, block.slot, proposer_index)
     privkey = privkeys[proposer_index]
     domain = spec.get_domain(state, spec.DOMAIN_BEACON_PROPOSER, spec.compute_epoch_at_slot(block.slot))
-    message = spec.compute_signing_root(block, domain)
+    signing_root = spec.compute_signing_root(block, domain)
 
-    signed_block.signature = bls.Sign(privkey, message)
+    signed_block.signature = bls.Sign(privkey, signing_root)
 
 
 def sign_block(spec, state, block, proposer_index=None):
diff --git a/test_libs/pyspec/eth2spec/test/helpers/block_header.py b/test_libs/pyspec/eth2spec/test/helpers/block_header.py
index bb5fe692f..c1bc746cc 100644
--- a/test_libs/pyspec/eth2spec/test/helpers/block_header.py
+++ b/test_libs/pyspec/eth2spec/test/helpers/block_header.py
@@ -6,6 +6,6 @@ def sign_block_header(spec, state, header, privkey):
         state=state,
         domain_type=spec.DOMAIN_BEACON_PROPOSER,
     )
-    message = spec.compute_signing_root(header, domain)
-    signature = bls.Sign(privkey, message)
+    signing_root = spec.compute_signing_root(header, domain)
+    signature = bls.Sign(privkey, signing_root)
     return spec.SignedBeaconBlockHeader(message=header, signature=signature)
diff --git a/test_libs/pyspec/eth2spec/test/helpers/custody.py b/test_libs/pyspec/eth2spec/test/helpers/custody.py
index f75cb9607..e00d64a17 100644
--- a/test_libs/pyspec/eth2spec/test/helpers/custody.py
+++ b/test_libs/pyspec/eth2spec/test/helpers/custody.py
@@ -18,13 +18,13 @@ def get_valid_early_derived_secret_reveal(spec, state, epoch=None):
 
     # Generate the secret that is being revealed
     domain = spec.get_domain(state, spec.DOMAIN_RANDAO, epoch)
-    message = spec.compute_signing_root(spec.Epoch(epoch), domain)
-    reveal = bls.Sign(privkeys[revealed_index], message)
+    signing_root = spec.compute_signing_root(spec.Epoch(epoch), domain)
+    reveal = bls.Sign(privkeys[revealed_index], signing_root)
     # Generate the mask (any random 32 bytes that don't reveal the masker's secret will do)
     mask = hash(reveal)
     # Generate masker's signature on the mask
-    message = spec.compute_signing_root(mask, domain)
-    masker_signature = bls.Sign(privkeys[masker_index], message)
+    signing_root = spec.compute_signing_root(mask, domain)
+    masker_signature = bls.Sign(privkeys[masker_index], signing_root)
     masked_reveal = bls.Aggregate([reveal, masker_signature])
 
     return spec.EarlyDerivedSecretReveal(
@@ -48,8 +48,8 @@ def get_valid_custody_key_reveal(spec, state, period=None):
 
     # Generate the secret that is being revealed
     domain = spec.get_domain(state, spec.DOMAIN_RANDAO, epoch_to_sign)
-    message = spec.compute_signing_root(spec.Epoch(epoch_to_sign), domain)
-    reveal = bls.Sign(privkeys[revealer_index], message)
+    signing_root = spec.compute_signing_root(spec.Epoch(epoch_to_sign), domain)
+    reveal = bls.Sign(privkeys[revealer_index], signing_root)
     return spec.CustodyKeyReveal(
         revealer_index=revealer_index,
         reveal=reveal,
@@ -74,8 +74,8 @@ def get_valid_bit_challenge(spec, state, attestation, invalid_custody_bit=False)
 
     # Generate the responder key
     domain = spec.get_domain(state, spec.DOMAIN_RANDAO, epoch)
-    message = spec.compute_signing_root(spec.compute_signing_root, domain)
-    responder_key = bls.Sign(privkeys[responder_index], message)
+    signing_root = spec.compute_signing_root(spec.Epoch(epoch), domain)
+    responder_key = bls.Sign(privkeys[responder_index], signing_root)
 
     chunk_count = spec.get_custody_chunk_count(attestation.data.crosslink)
 
diff --git a/test_libs/pyspec/eth2spec/test/helpers/deposits.py b/test_libs/pyspec/eth2spec/test/helpers/deposits.py
index 720704576..337ad7d82 100644
--- a/test_libs/pyspec/eth2spec/test/helpers/deposits.py
+++ b/test_libs/pyspec/eth2spec/test/helpers/deposits.py
@@ -30,8 +30,8 @@ def sign_deposit_data(spec, deposit_data, privkey, state=None):
         pubkey=deposit_data.pubkey,
         withdrawal_credentials=deposit_data.withdrawal_credentials,
         amount=deposit_data.amount)
-    message = spec.compute_signing_root(deposit_message, domain)
-    deposit_data.signature = bls.Sign(privkey, message)
+    signing_root = spec.compute_signing_root(deposit_message, domain)
+    deposit_data.signature = bls.Sign(privkey, signing_root)
 
 
 def build_deposit(spec,
diff --git a/test_libs/pyspec/eth2spec/test/helpers/phase1/attestations.py b/test_libs/pyspec/eth2spec/test/helpers/phase1/attestations.py
index 7947ba811..622183fe9 100644
--- a/test_libs/pyspec/eth2spec/test/helpers/phase1/attestations.py
+++ b/test_libs/pyspec/eth2spec/test/helpers/phase1/attestations.py
@@ -26,5 +26,5 @@ def sign_shard_attestation(spec, beacon_state, shard_state, block, participants)
 
 def get_attestation_signature(spec, beacon_state, shard_state, message_hash, block_epoch, privkey):
     domain = spec.get_domain(beacon_state, spec.DOMAIN_SHARD_ATTESTER, block_epoch)
-    message = spec.compute_signing_root(message_hash, domain)
-    return bls.Sign(privkey, message)
+    signing_root = spec.compute_signing_root(message_hash, domain)
+    return bls.Sign(privkey, signing_root)
diff --git a/test_libs/pyspec/eth2spec/test/helpers/phase1/shard_block.py b/test_libs/pyspec/eth2spec/test/helpers/phase1/shard_block.py
index a72a50649..6e1fba8dc 100644
--- a/test_libs/pyspec/eth2spec/test/helpers/phase1/shard_block.py
+++ b/test_libs/pyspec/eth2spec/test/helpers/phase1/shard_block.py
@@ -19,8 +19,8 @@ def sign_shard_block(spec, beacon_state, shard_state, block, proposer_index=None
 
     privkey = privkeys[proposer_index]
     domain = spec.get_domain(beacon_state, spec.DOMAIN_SHARD_PROPOSER, spec.compute_epoch_of_shard_slot(block.slot))
-    message = spec.compute_signing_root(block, domain)
-    block.signature = bls.Sign(privkey, message)
+    signing_root = spec.compute_signing_root(block, domain)
+    block.signature = bls.Sign(privkey, signing_root)
 
 
 def build_empty_shard_block(spec,
diff --git a/test_libs/pyspec/eth2spec/test/helpers/voluntary_exits.py b/test_libs/pyspec/eth2spec/test/helpers/voluntary_exits.py
index f186f1533..55310ef7d 100644
--- a/test_libs/pyspec/eth2spec/test/helpers/voluntary_exits.py
+++ b/test_libs/pyspec/eth2spec/test/helpers/voluntary_exits.py
@@ -3,8 +3,8 @@ from eth2spec.utils import bls
 
 def sign_voluntary_exit(spec, state, voluntary_exit, privkey):
     domain = spec.get_domain(state, spec.DOMAIN_VOLUNTARY_EXIT, voluntary_exit.epoch)
-    message = spec.compute_signing_root(voluntary_exit, domain)
+    signing_root = spec.compute_signing_root(voluntary_exit, domain)
     return spec.SignedVoluntaryExit(
         message=voluntary_exit,
-        signature=bls.Sign(privkey, message)
+        signature=bls.Sign(privkey, signing_root)
     )
diff --git a/test_libs/pyspec/eth2spec/test/sanity/test_blocks.py b/test_libs/pyspec/eth2spec/test/sanity/test_blocks.py
index ae02d8c1a..b386d36b4 100644
--- a/test_libs/pyspec/eth2spec/test/sanity/test_blocks.py
+++ b/test_libs/pyspec/eth2spec/test/sanity/test_blocks.py
@@ -108,10 +108,10 @@ def test_invalid_block_sig(spec, state):
 
     block = build_empty_block_for_next_slot(spec, state)
     domain = spec.get_domain(state, spec.DOMAIN_BEACON_PROPOSER, spec.compute_epoch_at_slot(block.slot))
-    message = spec.compute_signing_root(block, domain)
+    signing_root = spec.compute_signing_root(block, domain)
     invalid_signed_block = spec.SignedBeaconBlock(
         message=block,
-        signature=bls.Sign(123456, message)
+        signature=bls.Sign(123456, signing_root)
     )
     expect_assertion_error(lambda: spec.state_transition(state, invalid_signed_block))
 
@@ -417,10 +417,10 @@ def test_voluntary_exit(spec, state):
         validator_index=validator_index,
     )
     domain = spec.get_domain(state, spec.DOMAIN_VOLUNTARY_EXIT)
-    message = spec.compute_signing_root(voluntary_exit, domain)
+    signing_root = spec.compute_signing_root(voluntary_exit, domain)
     signed_voluntary_exit = spec.SignedVoluntaryExit(
         message=voluntary_exit,
-        signature=bls.Sign(privkeys[validator_index], message)
+        signature=bls.Sign(privkeys[validator_index], signing_root)
     )
 
     # Add to state via block transition