编程实现基于属性的访问控制模型ABAC，创建主体S，客体O，环境E，操作O，创建访问控制策略，启用可信引用监测器，进行决策，决策结果为允许或拒绝

ABAC（Attribute-Based Access Control）是基于属性的访问控制模型，它使用属性来描述主体、客体和环境，并且使用属性之间的关系来制定访问控制策略。以下是一个Python实现的ABAC模型：

# 定义主体、客体、环境和操作
class Subject:
    def __init__(self, attributes):
        self.attributes = attributes

class Object:
    def __init__(self, attributes):
        self.attributes = attributes

class Environment:
    def __init__(self, attributes):
        self.attributes = attributes

class Operation:
    def __init__(self, name):
        self.name = name

# 定义访问控制策略和条件
class Policy:
    def __init__(self, subject_attr, object_attr, environment_attr, operation_name):
        self.subject_attr = subject_attr
        self.object_attr = object_attr
        self.environment_attr = environment_attr
        self.operation_name = operation_name

    def evaluate(self, subject, object, environment):
        if all(key in subject.attributes and subject.attributes[key] == value for key, value in self.subject_attr.items()) \
                and all(key in object.attributes and object.attributes[key] == value for key, value in self.object_attr.items()) \
                and all(key in environment.attributes and environment.attributes[key] == value for key, value in self.environment_attr.items()):
            return True
        else:
            return False

# 定义可信引用监测器
class ReferenceMonitor:
    def __init__(self):
        self.policy_list = []

    def add_policy(self, policy):
        self.policy_list.append(policy)

    def evaluate_access(self, subject, object, environment, operation):
        for policy in self.policy_list:
            if policy.operation_name == operation.name and policy.evaluate(subject, object, environment):
                return True
        return False

# 创建主体、客体、环境和操作
subject = Subject({'user_id': '123', 'role': 'admin'})
object = Object({'data_type': 'customer', 'location': 'US'})
environment = Environment({'time_of_day': 'morning'})
operation = Operation('read')

# 创建访问控制策略
policy1 = Policy({'user_id': '123', 'role': 'admin'}, {'data_type': 'customer'}, {'time_of_day': 'morning'}, 'read')
policy2 = Policy({'user_id': '456', 'role': 'user'}, {'data_type': 'customer', 'location': 'US'}, {'time_of_day': 'evening'}, 'read')

# 启用可信引用监测器
reference_monitor = ReferenceMonitor()
reference_monitor.add_policy(policy1)
reference_monitor.add_policy(policy2)

# 进行决策
decision = reference_monitor.evaluate_access(subject, object, environment, operation)

# 判断决策结果
if decision:
    print('Access granted!')
else:
    print('Access denied!')

在上面的代码中，我们首先定义了主体、客体、环境和操作的类。然后定义了访问控制策略的类和它的 evaluate 方法来判断是否满足策略条件。接着定义了可信引用监测器的类和它的 evaluate_access 方法来判断是否满足任何一个访问控制策略。最后，我们创建了一个主体、客体、环境和操作，创建了两个访问控制策略，并且将它们添加到可信引用监测器中。最后，我们调用可信引用监测器的 evaluate_access 方法来进行访问决策的判断。