def visitStatementList(self, ast: StatementList):
"""
Rule (1)
All statements are transformed individually.
Whenever the transformation of a statement requires the introduction of additional statements
(the CircuitHelper indicates this by storing them in the statement's pre_statements list), they are prepended to the transformed
statement in the list.
If transformation changes the appearance of a statement (apart from type changes),
the statement is wrapped in a comment block which displays the original statement's code.
"""
new_statements = []
for idx, stmt in enumerate(ast.statements):
old_code = stmt.code()
transformed_stmt = self.visit(stmt)
if transformed_stmt is None:
continue
old_code_wo_annotations = re.sub(r'(?=\b)me(?=\b)', 'msg.sender',
re.sub(f'@{WS_PATTERN}*{ID_PATTERN}', '', old_code))
new_code_wo_annotation_comments = re.sub(r'/\*.*?\*/', '', transformed_stmt.code())
if old_code_wo_annotations == new_code_wo_annotation_comments:
new_statements.append(transformed_stmt)
else:
new_statements += Comment.comment_wrap_block(old_code, transformed_stmt.pre_statements + [transformed_stmt])
if new_statements and isinstance(new_statements[-1], BlankLine):
new_statements = new_statements[:-1]
ast.statements = new_statements
return ast
def visitStatementList(self, ast: StatementList):
ast.after_analysis = self.propagate(ast.statements,
ast.before_analysis)
def create_external_wrapper_body(int_fct: ConstructorOrFunctionDefinition, ext_circuit: CircuitHelper,
original_params: List[Parameter], requires_proof: bool) -> Block:
"""
Return Block with external wrapper function body.
:param int_fct: corresponding internal function
:param ext_circuit: [SIDE EFFECT] circuit helper of the external wrapper function
:param original_params: list of transformed function parameters without additional parameters added due to transformation
:return: body with wrapper code
"""
priv_args = [p for p in original_params if p.annotated_type.is_cipher()]
args_backends = OrderedDict.fromkeys([p.annotated_type.type_name.crypto_params for p in priv_args])
stmts = []
for crypto_params in args_backends:
assert crypto_params in int_fct.used_crypto_backends
# If there are any private arguments with homomorphism 'hom', we need the public key for that crypto backend
ext_circuit._require_public_key_for_label_at(None, Expression.me_expr(), crypto_params)
for crypto_params in cfg.all_crypto_params():
if crypto_params.is_symmetric_cipher():
if (MeExpr(), crypto_params) in ext_circuit.requested_global_keys or crypto_params in args_backends:
# Make sure msg.sender's key pair is available in the circuit
stmts += ext_circuit.request_private_key(crypto_params)
# Verify that out parameter has correct size
stmts += [RequireStatement(IdentifierExpr(cfg.zk_out_name).dot('length').binop('==', NumberLiteralExpr(ext_circuit.out_size_trans)))]
# IdentifierExpr for array var holding serialized public circuit inputs
in_arr_var = IdentifierExpr(cfg.zk_in_name).as_type(Array(AnnotatedTypeName.uint_all()))
# Request static public keys
offset = 0
key_req_stmts = []
me_key_idx: Dict[CryptoParams, int] = {}
if ext_circuit.requested_global_keys:
# Ensure that me public key is stored starting at in[0]
keys = [key for key in ext_circuit.requested_global_keys]
tmp_keys = {}
for crypto_params in int_fct.used_crypto_backends:
tmp_key_var = Identifier(f'_tmp_key_{crypto_params.identifier_name}')
key_req_stmts.append(tmp_key_var.decl_var(AnnotatedTypeName.key_type(crypto_params)))
tmp_keys[crypto_params] = tmp_key_var
for (key_owner, crypto_params) in keys:
tmp_key_var = tmp_keys[crypto_params]
idf, assignment = ext_circuit.request_public_key(crypto_params, key_owner, ext_circuit.get_glob_key_name(key_owner, crypto_params))
assignment.lhs = IdentifierExpr(tmp_key_var.clone())
key_req_stmts.append(assignment)
# Remember me-keys for later use in symmetrically encrypted keys
if key_owner == MeExpr():
assert crypto_params not in me_key_idx
me_key_idx[crypto_params] = offset
# Manually add to circuit inputs
key_len = crypto_params.key_len
key_req_stmts.append(in_arr_var.slice(offset, key_len).assign(IdentifierExpr(tmp_key_var.clone()).slice(0, key_len)))
offset += key_len
assert offset == ext_circuit.in_size
# Check encrypted parameters
param_stmts = []
for p in original_params:
""" * of T_e rule 8 """
if p.annotated_type.is_cipher():
cipher_payload_len = p.annotated_type.type_name.crypto_params.cipher_payload_len
assign_stmt = in_arr_var.slice(offset, cipher_payload_len).assign(IdentifierExpr(p.idf.clone()).slice(0, cipher_payload_len))
ext_circuit.ensure_parameter_encryption(assign_stmt, p)
# Manually add to circuit inputs
param_stmts.append(assign_stmt)
offset += cipher_payload_len
# Populate sender field of parameters encrypted with a symmetric cipher
copy_stmts = []
for p in original_params:
if p.annotated_type.is_cipher():
c = p.annotated_type.type_name
assert isinstance(c, CipherText)
if c.crypto_params.is_symmetric_cipher():
sender_key = in_arr_var.index(me_key_idx[c.crypto_params])
idf = IdentifierExpr(p.idf.clone()).as_type(p.annotated_type.clone())
cipher_payload_len = cfg.get_crypto_params(p.annotated_type.homomorphism).cipher_payload_len
lit = ArrayLiteralExpr([idf.clone().index(i) for i in range(cipher_payload_len)] + [sender_key])
copy_stmts.append(VariableDeclarationStatement(VariableDeclaration([], p.annotated_type.clone(), p.idf.clone(), 'memory'), lit))
if copy_stmts:
param_stmts += [Comment(), Comment('Copy from calldata to memory and set sender field')] + copy_stmts
# Declare in array
new_in_array_expr = NewExpr(AnnotatedTypeName(TypeName.dyn_uint_array()), [NumberLiteralExpr(ext_circuit.in_size_trans)])
in_var_decl = in_arr_var.idf.decl_var(TypeName.dyn_uint_array(), new_in_array_expr)
stmts.append(in_var_decl)
stmts.append(Comment())
stmts += Comment.comment_wrap_block('Request static public keys', key_req_stmts)
stmts += Comment.comment_wrap_block('Backup private arguments for verification', param_stmts)
# Call internal function
args = [IdentifierExpr(param.idf.clone()) for param in original_params]
internal_call = FunctionCallExpr(IdentifierExpr(int_fct.idf.clone()).override(target=int_fct), args)
internal_call.sec_start_offset = ext_circuit.priv_in_size
if int_fct.requires_verification:
ext_circuit.call_function(internal_call)
args += [in_arr_var.clone(), NumberLiteralExpr(ext_circuit.in_size),
IdentifierExpr(cfg.zk_out_name), NumberLiteralExpr(ext_circuit.out_size)]
if int_fct.return_parameters:
stmts += Comment.comment_list("Declare return variables", [VariableDeclarationStatement(deep_copy(vd)) for vd in int_fct.return_var_decls])
in_call = TupleExpr([IdentifierExpr(vd.idf.clone()) for vd in int_fct.return_var_decls]).assign(internal_call)
else:
in_call = ExpressionStatement(internal_call)
stmts.append(Comment("Call internal function"))
stmts.append(in_call)
stmts.append(Comment())
# Call verifier
if requires_proof and not cfg.disable_verification:
verifier = IdentifierExpr(cfg.get_contract_var_name(ext_circuit.verifier_contract_type.code()))
verifier_args = [IdentifierExpr(cfg.proof_param_name), IdentifierExpr(cfg.zk_in_name), IdentifierExpr(cfg.zk_out_name)]
verify = ExpressionStatement(verifier.call(cfg.verification_function_name, verifier_args))
stmts.append(StatementList([Comment('Verify zk proof of execution'), verify], excluded_from_simulation=True))
# Add return statement at the end if necessary
if int_fct.return_parameters:
stmts.append(ReturnStatement(TupleExpr([IdentifierExpr(vd.idf.clone()) for vd in int_fct.return_var_decls])))
return Block(stmts)
def create_internal_verification_wrapper(self, ast: ConstructorOrFunctionDefinition):
"""
Add the necessary additional parameters and boiler plate code for verification support to the given function.
:param ast: [SIDE EFFECT] Internal function which requires verification
"""
circuit = self.circuits[ast]
stmts = []
symmetric_cipher_used = any([backend.is_symmetric_cipher() for backend in ast.used_crypto_backends])
if symmetric_cipher_used and 'pure' in ast.modifiers:
# Symmetric trafo requires msg.sender access -> change from pure to view
ast.modifiers = ['view' if mod == 'pure' else mod for mod in ast.modifiers]
# Add additional params
ast.add_param(Array(AnnotatedTypeName.uint_all()), cfg.zk_in_name)
ast.add_param(AnnotatedTypeName.uint_all(), f'{cfg.zk_in_name}_start_idx')
ast.add_param(Array(AnnotatedTypeName.uint_all()), cfg.zk_out_name)
ast.add_param(AnnotatedTypeName.uint_all(), f'{cfg.zk_out_name}_start_idx')
# Verify that in/out parameters have correct size
out_start_idx, in_start_idx = IdentifierExpr(f'{cfg.zk_out_name}_start_idx'), IdentifierExpr(f'{cfg.zk_in_name}_start_idx')
out_var, in_var = IdentifierExpr(cfg.zk_out_name), IdentifierExpr(cfg.zk_in_name).as_type(Array(AnnotatedTypeName.uint_all()))
stmts.append(RequireStatement(out_start_idx.binop('+', NumberLiteralExpr(circuit.out_size_trans)).binop('<=', out_var.dot('length'))))
stmts.append(RequireStatement(in_start_idx.binop('+', NumberLiteralExpr(circuit.in_size_trans)).binop('<=', in_var.dot('length'))))
# Declare zk_data struct var (if needed)
if circuit.requires_zk_data_struct():
zk_struct_type = StructTypeName([Identifier(circuit.zk_data_struct_name)])
stmts += [Identifier(cfg.zk_data_var_name).decl_var(zk_struct_type), BlankLine()]
# Declare return variable if necessary
if ast.return_parameters:
stmts += Comment.comment_list("Declare return variables", [VariableDeclarationStatement(vd) for vd in ast.return_var_decls])
# Find all me-keys in the in array
me_key_idx: Dict[CryptoParams, int] = {}
offset = 0
for (key_owner, crypto_params) in circuit.requested_global_keys:
if key_owner == MeExpr():
assert crypto_params not in me_key_idx
me_key_idx[crypto_params] = offset
offset += crypto_params.key_len
# Deserialize out array (if any)
deserialize_stmts = []
offset = 0
for s in circuit.output_idfs:
deserialize_stmts.append(s.deserialize(cfg.zk_out_name, out_start_idx, offset))
if isinstance(s.t, CipherText) and s.t.crypto_params.is_symmetric_cipher():
# Assign sender field to user-encrypted values if necessary
# Assumption: s.t.crypto_params.key_len == 1 for all symmetric ciphers
assert s.t.crypto_params in me_key_idx, "Symmetric cipher but did not request me key"
key_idx = me_key_idx[s.t.crypto_params]
sender_key = in_var.index(key_idx)
cipher_payload_len = s.t.crypto_params.cipher_payload_len
deserialize_stmts.append(s.get_loc_expr().index(cipher_payload_len).assign(sender_key))
offset += s.t.size_in_uints
if deserialize_stmts:
stmts.append(StatementList(Comment.comment_wrap_block("Deserialize output values", deserialize_stmts), excluded_from_simulation=True))
# Include original transformed function body
stmts += ast.body.statements
# Serialize in parameters to in array (if any)
serialize_stmts = []
offset = 0
for s in circuit.input_idfs:
serialize_stmts += [s.serialize(cfg.zk_in_name, in_start_idx, offset)]
offset += s.t.size_in_uints
if offset:
stmts.append(Comment())
stmts += Comment.comment_wrap_block('Serialize input values', serialize_stmts)
# Add return statement at the end if necessary
# (was previously replaced by assignment to return_var by ZkayStatementTransformer)
if circuit.has_return_var:
stmts.append(ReturnStatement(TupleExpr([IdentifierExpr(vd.idf.clone()).override(target=vd) for vd in ast.return_var_decls])))
ast.body.statements[:] = stmts
def create_external_wrapper_body(int_fct: ConstructorOrFunctionDefinition,
ext_circuit: CircuitHelper,
original_params: List[Parameter],
requires_proof: bool) -> Block:
"""
Return Block with external wrapper function body.
:param int_fct: corresponding internal function
:param ext_circuit: [SIDE EFFECT] circuit helper of the external wrapper function
:param original_params: list of transformed function parameters without additional parameters added due to transformation
:return: body with wrapper code
"""
has_priv_args = any(
[p.annotated_type.is_cipher() for p in original_params])
stmts = []
if has_priv_args:
ext_circuit._require_public_key_for_label_at(
None, Expression.me_expr())
if cfg.is_symmetric_cipher():
# Make sure msg.sender's key pair is available in the circuit
assert any(isinstance(k, MeExpr) for k in ext_circuit.requested_global_keys) \
or has_priv_args, "requires verification => both sender keys required"
stmts += ext_circuit.request_private_key()
# Verify that out parameter has correct size
stmts += [
RequireStatement(
IdentifierExpr(cfg.zk_out_name).dot('length').binop(
'==', NumberLiteralExpr(ext_circuit.out_size_trans)))
]
# IdentifierExpr for array var holding serialized public circuit inputs
in_arr_var = IdentifierExpr(cfg.zk_in_name).as_type(
Array(AnnotatedTypeName.uint_all()))
# Find index of me's public key in requested_global_keys
glob_me_key_index = -1
for idx, e in enumerate(ext_circuit.requested_global_keys):
if isinstance(e, MeExpr):
glob_me_key_index = idx
break
# Request static public keys
offset = 0
key_req_stmts = []
if ext_circuit.requested_global_keys:
# Ensure that me public key is stored starting at in[0]
keys = [key for key in ext_circuit.requested_global_keys]
if glob_me_key_index != -1:
(keys[0], keys[glob_me_key_index]) = (keys[glob_me_key_index],
keys[0])
tmp_key_var = Identifier('_tmp_key')
key_req_stmts.append(
tmp_key_var.decl_var(AnnotatedTypeName.key_type()))
for key_owner in keys:
idf, assignment = ext_circuit.request_public_key(
key_owner, ext_circuit.get_glob_key_name(key_owner))
assignment.lhs = IdentifierExpr(tmp_key_var.clone())
key_req_stmts.append(assignment)
# Manually add to circuit inputs
key_req_stmts.append(
in_arr_var.slice(offset, cfg.key_len).assign(
IdentifierExpr(tmp_key_var.clone()).slice(
0, cfg.key_len)))
offset += cfg.key_len
assert offset == ext_circuit.in_size
# Check encrypted parameters
param_stmts = []
for p in original_params:
""" * of T_e rule 8 """
if p.annotated_type.is_cipher():
assign_stmt = in_arr_var.slice(
offset, cfg.cipher_payload_len).assign(
IdentifierExpr(p.idf.clone()).slice(
0, cfg.cipher_payload_len))
ext_circuit.ensure_parameter_encryption(assign_stmt, p)
# Manually add to circuit inputs
param_stmts.append(assign_stmt)
offset += cfg.cipher_payload_len
if cfg.is_symmetric_cipher():
# Populate sender field of encrypted parameters
copy_stmts = []
for p in original_params:
if p.annotated_type.is_cipher():
sender_key = in_arr_var.index(0)
idf = IdentifierExpr(p.idf.clone()).as_type(
p.annotated_type.clone())
lit = ArrayLiteralExpr([
idf.clone().index(i)
for i in range(cfg.cipher_payload_len)
] + [sender_key])
copy_stmts.append(
VariableDeclarationStatement(
VariableDeclaration([], p.annotated_type.clone(),
p.idf.clone(), 'memory'), lit))
if copy_stmts:
param_stmts += [
Comment(),
Comment(
'Copy from calldata to memory and set sender field')
] + copy_stmts
assert glob_me_key_index != -1, "Symmetric cipher but did not request me key"
# Declare in array
new_in_array_expr = NewExpr(
AnnotatedTypeName(TypeName.dyn_uint_array()),
[NumberLiteralExpr(ext_circuit.in_size_trans)])
in_var_decl = in_arr_var.idf.decl_var(TypeName.dyn_uint_array(),
new_in_array_expr)
stmts.append(in_var_decl)
stmts.append(Comment())
stmts += Comment.comment_wrap_block('Request static public keys',
key_req_stmts)
stmts += Comment.comment_wrap_block(
'Backup private arguments for verification', param_stmts)
# Call internal function
args = [IdentifierExpr(param.idf.clone()) for param in original_params]
internal_call = FunctionCallExpr(
IdentifierExpr(int_fct.idf.clone()).override(target=int_fct), args)
internal_call.sec_start_offset = ext_circuit.priv_in_size
if int_fct.requires_verification:
ext_circuit.call_function(internal_call)
args += [
in_arr_var.clone(),
NumberLiteralExpr(ext_circuit.in_size),
IdentifierExpr(cfg.zk_out_name),
NumberLiteralExpr(ext_circuit.out_size)
]
if int_fct.return_parameters:
stmts += Comment.comment_list("Declare return variables", [
VariableDeclarationStatement(deep_copy(vd))
for vd in int_fct.return_var_decls
])
in_call = TupleExpr([
IdentifierExpr(vd.idf.clone())
for vd in int_fct.return_var_decls
]).assign(internal_call)
else:
in_call = ExpressionStatement(internal_call)
stmts.append(Comment("Call internal function"))
stmts.append(in_call)
stmts.append(Comment())
# Call verifier
if requires_proof:
verifier = IdentifierExpr(
cfg.get_contract_var_name(
ext_circuit.verifier_contract_type.code()))
verifier_args = [
IdentifierExpr(cfg.proof_param_name),
IdentifierExpr(cfg.zk_in_name),
IdentifierExpr(cfg.zk_out_name)
]
verify = ExpressionStatement(
verifier.call(cfg.verification_function_name, verifier_args))
stmts.append(
StatementList(
[Comment('Verify zk proof of execution'), verify],
excluded_from_simulation=True))
# Add return statement at the end if necessary
if int_fct.return_parameters:
stmts.append(
ReturnStatement(
TupleExpr([
IdentifierExpr(vd.idf.clone())
for vd in int_fct.return_var_decls
])))
return Block(stmts)
def visitStatementList(self, ast: StatementList):
ast.names = collect_children_names(ast)