基于 pyasn1 的ASN1 编码入门

from __future__ import annotations

# 时间类型（UTCTime）
from pyasn1.type import char, univ, useful

# 整数类型（INTEGER）
age = univ.Integer(25)
print(f"INTEGER示例：{age.prettyPrint()}, 类型：{type(age)}")  # 输出：25

# 字节串（OCTET STRING）
data = univ.OctetString(b'\x01\x02\xFF')
print(f"OCTET STRING示例：{data.asOctets()}, 类型：{type(data)}")  # 输出：b'\x01\x02\xff'

# 可打印字符串（PrintableString）
name = char.PrintableString("Alice@2023")
print(f"字符串示例：{name.prettyPrint()}, 类型：{type(name)}")  # 输出：'Alice@2023'

# 布尔值（BOOLEAN）
flag = univ.Boolean(True)
print(f"布尔值示例：{flag.prettyPrint()}, 类型：{type(flag)}")  # 输出：True

# 对象标识符（OBJECT IDENTIFIER）
oid = univ.ObjectIdentifier('1.2.840.113549.1.1.1')  # RSA加密算法OID
print(f"OID示例：{oid.prettyPrint()}, 类型：{type(oid)}")  # 输出：1.2.840.113549.1.1.1

time = useful.UTCTime("250513120000Z")  # 2025-05-13 12:00:00 UTC
print(f"时间示例：{time.prettyPrint()}, 类型：{type(time)}")

# 中文、日文、韩文、泰语、越南语、印地语
utf8Str = char.UTF8String(
    "编码解码 エンコードとデコード 인코딩 및 디코딩 การเข้ารหัสและการถอดรหัส Mã hóa và Giải mã एन्कोडिंग और डिकोडिंग")
print(f"UTF8String示例：{utf8Str.prettyPrint()}, 类型：{type(utf8Str)}")

bitStr = univ.BitString(0B111000111)  # 可以指定任意长度的比特位
print(f"BitString示例：{bitStr.prettyPrint()}, 类型：{type(bitStr)}")

strList = univ.SequenceOf(char.UTF8String())  # 可以指定任意长度的字符串列表
for i in ['中文', '日文', '韩文', '泰语', '越南语', '印地语']:
    strList.append(char.UTF8String(i))
print(f"SequenceOf示例：{strList.prettyPrint()}, 类型：{type(strList)}, 元素类型：{strList.typeId}")

class MyStruct(univ.Sequence):
    componentType = namedtype.NamedTypes(
        namedtype.NamedType('myInt', univ.Integer()),
        namedtype.NamedType('myBool', univ.Boolean()),
        # ...其他字段...
    )

class InnerSeq(univ.Sequence):
    componentType = namedtype.NamedTypes(
        namedtype.NamedType('id', univ.Integer()),
        namedtype.NamedType('name', char.UTF8String())
    )

# 在主结构体中嵌套
my_struct['mySequence'] = inner_seq

# 整数列表
intList = univ.SequenceOf(univ.Integer())
for num in [1,2,3,4,5]:
    intList.append(univ.Integer(num))

# 结构体列表
seqOfSeq = univ.SequenceOf(InnerSeq())
seqOfSeq.append(InnerSeq().setComponents(...))

from __future__ import annotations

from pyasn1.codec.der import decoder, encoder
from pyasn1.type import char, namedtype, univ, useful


# 定义内嵌的Sequence类型
class InnerSeq(univ.Sequence):
    componentType = namedtype.NamedTypes(
        namedtype.NamedType('id', univ.Integer()),
        namedtype.NamedType('name', char.UTF8String()),
        namedtype.NamedType('enabled', univ.Boolean())
    )


# 主结构体
class MyStruct(univ.Sequence):
    componentType = namedtype.NamedTypes(
        namedtype.NamedType('myInt', univ.Integer()),  # INTEGER
        namedtype.NamedType('myBool', univ.Boolean()),  # BOOLEAN
        namedtype.NamedType('myOctets', univ.OctetString()),  # OCTET STRING
        namedtype.NamedType('myUtf8', char.UTF8String()),  # UTF8String
        namedtype.NamedType('myNull', univ.Null()),  # NULL
        namedtype.NamedType('myOid', univ.ObjectIdentifier()),  # OBJECT IDENTIFIER
        namedtype.NamedType('myBitStr', univ.BitString()),  # BIT STRING
        namedtype.NamedType('myTime', useful.UTCTime()),  # UTCTime
        namedtype.NamedType('mySequence', InnerSeq()),  # 嵌套Sequence,可以理解为嵌套的结构体
        namedtype.NamedType('intList', univ.SequenceOf(
            univ.Integer())),  # SequenceOf INTEGER
        namedtype.NamedType('seqOfSeq', univ.SequenceOf(
            InnerSeq()))  # SequenceOf InnerSeq
    )


# 创建数据实例
my_struct = MyStruct()

# 基本类型赋值
my_struct['myInt'] = 2025
my_struct['myBool'] = True
my_struct['myOctets'] = b'\x01\x02\x03'
my_struct['myInt'] = 123456789
my_struct['myBool'] = True
my_struct['myUtf8'] = '你好，世界'
my_struct['myNull'] = univ.Null()
my_struct['myOid'] = '1.3.6.1.4.1.99999'  # OBJECT IDENTIFIER
# my_struct['myBitStr'] = univ.BitString.fromHexString('FACE')  # 二进制位字符串
my_struct['myBitStr'] = 0b10101  # 二进制位字符串
my_struct['myTime'] = '230501120000Z'  # UTC时间(2023-05-01 12:00:00)

# 嵌套Sequence赋值
inner_seq = InnerSeq()
inner_seq['id'] = 65535
inner_seq['name'] = '嵌套结构'
inner_seq['enabled'] = False
my_struct['mySequence'] = inner_seq

# SequenceOf INTEGER赋值
# 正确赋值
for num in [1, 2, 3, 4, 5]:
    my_struct['intList'].append(univ.Integer(num))  # 正确方式

# SequenceOf InnerSeq赋值
seq_of_seq = [
    InnerSeq().setComponents(1, '第一个', True),
    InnerSeq().setComponents(2, '第二个', False)
]
for item in seq_of_seq:
    my_struct['seqOfSeq'].append(item)  # 正确方式

# DER编码
der_data = encoder.encode(my_struct)
print("DER编码结果:", der_data.hex())

# DER解码
decoded_struct, _ = decoder.decode(der_data, asn1Spec = MyStruct())

print(f"解码验证成功! decoded_struct类型：{type(decoded_struct)}")
print("嵌套Sequence:", decoded_struct['mySequence'].prettyPrint())
print("整数列表:", list(decoded_struct['intList']))
print("结构体列表:")
for i, item in enumerate(decoded_struct['seqOfSeq']):
    print(f"  结构体{i + 1}:", item.prettyPrint())