type
Post
status
Published
date
Jul 4, 2022
slug
n1AES
summary
n1AES
tags
Crypto
CTF
category
CRYPTO
icon
password
n1AES
看加密函数
def encrypt(self, plaintext): self.plain_state = text2matrix(plaintext) self.add_round_key(self.plain_state, self.round_keys[:4]) for i in range(1, 10): self.round_encrypt(self.plain_state, self.round_keys[4 * i: 4 * (i + 1)]) self.sub_bytes(self.plain_state) self.shift_rows(self.plain_state) self.add_round_key(self.plain_state, self.round_keys[40:]) return matrix2text(self.plain_state)
那么解密函数就是
def decrypt(self, plaintext): self.plain_state = text2matrix(plaintext) self.add_round_key(self.plain_state, self.round_keys[40:]) self._shift_rows(self.plain_state) self._sub_bytes(self.plain_state) for i in range(9, 0,-1): self.round_decrypt(self.plain_state, self.round_keys[4 * i: 4 * (i + 1)]) self.add_round_key(self.plain_state, self.round_keys[:4]) return matrix2text(self.plain_state)
shift_rows的逆函数
def _shift_rows(self, s): r = [14, 12, 10, 11, 3, 2, 0, 13, 9, 5, 4, 8, 15, 1, 6, 7] t = [] for i in xrange(4): for j in xrange(4): t.append(s[i][j]) for i in xrange(16): s[i/4][i%4] = t[r.index(i)]
sub_bytes 的逆函数
def _sub_bytes(self, s): for i in range(4): for j in range(4): s[i][j] = InvSbox[s[i][j]]
round_decrypt函数
def round_decrypt(self, state_matrix, key_matrix): self.add_round_key(state_matrix, key_matrix) self._mix_columns(state_matrix) self._shift_rows(state_matrix) self._sub_bytes(state_matrix)
主要是列混淆的逆函数
def _mix_columns(self, s): wt = [99, 214, 252, 197] for i in range(4): s0 = xx(s[0][i],wt[0]) ^ xx(s[1][i],wt[1]) ^ xx(s[2][i],wt[2]) ^ xx(s[3][i],wt[3]) s1 = xx(s[0][i],wt[1]) ^ xx(s[1][i],wt[2]) ^ xx(s[2][i],wt[3]) ^ xx(s[3][i],wt[0]) s2 = xx(s[0][i],wt[2]) ^ xx(s[1][i],wt[3]) ^ xx(s[2][i],wt[0]) ^ xx(s[3][i],wt[1]) s3 = xx(s[0][i],wt[3]) ^ xx(s[1][i],wt[0]) ^ xx(s[2][i],wt[1]) ^ xx(s[3][i],wt[2]) s[0][i] = s0 s[1][i] = s1 s[2][i] = s2 s[3][i] = s3
主要是需要算出[3, 10, 8, 6]在模P多项式P(x) = x^8 + x^6 + x^2 + 1下的逆
不太懂怎么算
exp
def xor(a, b): return ''.join(chr(ord(ac) ^ ord(bc)) for ac, bc in zip(a, b)) Sbox = ( 0x63, 0x7C, 0x77, 0x7B, 0xF2, 0x6B, 0x6F, 0xC5, 0x30, 0x01, 0x67, 0x2B, 0xFE, 0xD7, 0xAB, 0x76, 0xCA, 0x82, 0xC9, 0x7D, 0xFA, 0x59, 0x47, 0xF0, 0xAD, 0xD4, 0xA2, 0xAF, 0x9C, 0xA4, 0x72, 0xC0, 0xB7, 0xFD, 0x93, 0x26, 0x36, 0x3F, 0xF7, 0xCC, 0x34, 0xA5, 0xE5, 0xF1, 0x71, 0xD8, 0x31, 0x15, 0x04, 0xC7, 0x23, 0xC3, 0x18, 0x96, 0x05, 0x9A, 0x07, 0x12, 0x80, 0xE2, 0xEB, 0x27, 0xB2, 0x75, 0x09, 0x83, 0x2C, 0x1A, 0x1B, 0x6E, 0x5A, 0xA0, 0x52, 0x3B, 0xD6, 0xB3, 0x29, 0xE3, 0x2F, 0x84, 0x53, 0xD1, 0x00, 0xED, 0x20, 0xFC, 0xB1, 0x5B, 0x6A, 0xCB, 0xBE, 0x39, 0x4A, 0x4C, 0x58, 0xCF, 0xD0, 0xEF, 0xAA, 0xFB, 0x43, 0x4D, 0x33, 0x85, 0x45, 0xF9, 0x02, 0x7F, 0x50, 0x3C, 0x9F, 0xA8, 0x51, 0xA3, 0x40, 0x8F, 0x92, 0x9D, 0x38, 0xF5, 0xBC, 0xB6, 0xDA, 0x21, 0x10, 0xFF, 0xF3, 0xD2, 0xCD, 0x0C, 0x13, 0xEC, 0x5F, 0x97, 0x44, 0x17, 0xC4, 0xA7, 0x7E, 0x3D, 0x64, 0x5D, 0x19, 0x73, 0x60, 0x81, 0x4F, 0xDC, 0x22, 0x2A, 0x90, 0x88, 0x46, 0xEE, 0xB8, 0x14, 0xDE, 0x5E, 0x0B, 0xDB, 0xE0, 0x32, 0x3A, 0x0A, 0x49, 0x06, 0x24, 0x5C, 0xC2, 0xD3, 0xAC, 0x62, 0x91, 0x95, 0xE4, 0x79, 0xE7, 0xC8, 0x37, 0x6D, 0x8D, 0xD5, 0x4E, 0xA9, 0x6C, 0x56, 0xF4, 0xEA, 0x65, 0x7A, 0xAE, 0x08, 0xBA, 0x78, 0x25, 0x2E, 0x1C, 0xA6, 0xB4, 0xC6, 0xE8, 0xDD, 0x74, 0x1F, 0x4B, 0xBD, 0x8B, 0x8A, 0x70, 0x3E, 0xB5, 0x66, 0x48, 0x03, 0xF6, 0x0E, 0x61, 0x35, 0x57, 0xB9, 0x86, 0xC1, 0x1D, 0x9E, 0xE1, 0xF8, 0x98, 0x11, 0x69, 0xD9, 0x8E, 0x94, 0x9B, 0x1E, 0x87, 0xE9, 0xCE, 0x55, 0x28, 0xDF, 0x8C, 0xA1, 0x89, 0x0D, 0xBF, 0xE6, 0x42, 0x68, 0x41, 0x99, 0x2D, 0x0F, 0xB0, 0x54, 0xBB, 0x16, ) InvSbox = ( 0x52, 0x09, 0x6A, 0xD5, 0x30, 0x36, 0xA5, 0x38, 0xBF, 0x40, 0xA3, 0x9E, 0x81, 0xF3, 0xD7, 0xFB, 0x7C, 0xE3, 0x39, 0x82, 0x9B, 0x2F, 0xFF, 0x87, 0x34, 0x8E, 0x43, 0x44, 0xC4, 0xDE, 0xE9, 0xCB, 0x54, 0x7B, 0x94, 0x32, 0xA6, 0xC2, 0x23, 0x3D, 0xEE, 0x4C, 0x95, 0x0B, 0x42, 0xFA, 0xC3, 0x4E, 0x08, 0x2E, 0xA1, 0x66, 0x28, 0xD9, 0x24, 0xB2, 0x76, 0x5B, 0xA2, 0x49, 0x6D, 0x8B, 0xD1, 0x25, 0x72, 0xF8, 0xF6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xD4, 0xA4, 0x5C, 0xCC, 0x5D, 0x65, 0xB6, 0x92, 0x6C, 0x70, 0x48, 0x50, 0xFD, 0xED, 0xB9, 0xDA, 0x5E, 0x15, 0x46, 0x57, 0xA7, 0x8D, 0x9D, 0x84, 0x90, 0xD8, 0xAB, 0x00, 0x8C, 0xBC, 0xD3, 0x0A, 0xF7, 0xE4, 0x58, 0x05, 0xB8, 0xB3, 0x45, 0x06, 0xD0, 0x2C, 0x1E, 0x8F, 0xCA, 0x3F, 0x0F, 0x02, 0xC1, 0xAF, 0xBD, 0x03, 0x01, 0x13, 0x8A, 0x6B, 0x3A, 0x91, 0x11, 0x41, 0x4F, 0x67, 0xDC, 0xEA, 0x97, 0xF2, 0xCF, 0xCE, 0xF0, 0xB4, 0xE6, 0x73, 0x96, 0xAC, 0x74, 0x22, 0xE7, 0xAD, 0x35, 0x85, 0xE2, 0xF9, 0x37, 0xE8, 0x1C, 0x75, 0xDF, 0x6E, 0x47, 0xF1, 0x1A, 0x71, 0x1D, 0x29, 0xC5, 0x89, 0x6F, 0xB7, 0x62, 0x0E, 0xAA, 0x18, 0xBE, 0x1B, 0xFC, 0x56, 0x3E, 0x4B, 0xC6, 0xD2, 0x79, 0x20, 0x9A, 0xDB, 0xC0, 0xFE, 0x78, 0xCD, 0x5A, 0xF4, 0x1F, 0xDD, 0xA8, 0x33, 0x88, 0x07, 0xC7, 0x31, 0xB1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xEC, 0x5F, 0x60, 0x51, 0x7F, 0xA9, 0x19, 0xB5, 0x4A, 0x0D, 0x2D, 0xE5, 0x7A, 0x9F, 0x93, 0xC9, 0x9C, 0xEF, 0xA0, 0xE0, 0x3B, 0x4D, 0xAE, 0x2A, 0xF5, 0xB0, 0xC8, 0xEB, 0xBB, 0x3C, 0x83, 0x53, 0x99, 0x61, 0x17, 0x2B, 0x04, 0x7E, 0xBA, 0x77, 0xD6, 0x26, 0xE1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0C, 0x7D, ) xtime = lambda a: (((a << 1) ^ 99) & 0xFF) if (a & 0x80) else (a << 1) Rcon = [0x0,0x1,0x2,0x4,0x8,0x10,0x20,0x40,0x80,0x1b,0x36,0x6c,0xd8,0xab,0x4d,0x9a,0x2f,0x5e,0xbc,0x63,0xc6,0x97,0x35,0x6a,0xd4,0xb3,0x7d,0xfa,0xef,0xc5,0x91,0x39] def xx(i,j): t = i res = 0 while j != 0: if j & 1: res ^= t t = xtime(t) j >>= 1 return res def text2matrix(text): matrix = [] for i in range(16): byte = ord(text[i]) if i % 4 == 0: matrix.append([byte]) else: matrix[i / 4].append(byte) return matrix def matrix2text(matrix): text = '' for i in range(4): for j in range(4): text = text + chr(matrix[i][j]) return text class N1AES: def __init__(self, master_key=None): if master_key: self.change_key(master_key) def change_key(self, master_key): self.skey = int(master_key.encode('hex'),16) self.round_keys = text2matrix(master_key) for i in range(4, 4 * 11): self.round_keys.append([]) if i % 4 == 0: byte = self.round_keys[i - 4][0] \ ^ Sbox[self.round_keys[i - 1][1]] \ ^ Rcon[i / 4] self.round_keys[i].append(byte) for j in range(1, 4): byte = self.round_keys[i - 4][j] \ ^ Sbox[self.round_keys[i - 1][(j + 1) % 4]] self.round_keys[i].append(byte) else: for j in range(4): byte = self.round_keys[i - 4][j] \ ^ self.round_keys[i - 1][j] self.round_keys[i].append(byte) def encrypt(self, plaintext): self.plain_state = text2matrix(plaintext) self.add_round_key(self.plain_state, self.round_keys[:4]) for i in range(1, 10): self.round_encrypt(self.plain_state, self.round_keys[4 * i: 4 * (i + 1)]) self.sub_bytes(self.plain_state) self.shift_rows(self.plain_state) self.add_round_key(self.plain_state, self.round_keys[40:]) return matrix2text(self.plain_state) def add_round_key(self, s, k): for i in range(4): for j in range(4): s[i][j] ^= k[i][j] def round_encrypt(self, state_matrix, key_matrix): self.sub_bytes(state_matrix) self.shift_rows(state_matrix) self.mix_columns(state_matrix) self.add_round_key(state_matrix, key_matrix) def sub_bytes(self, s): for i in range(4): for j in range(4): s[i][j] = Sbox[s[i][j]] def shift_rows(self, s): r = [14, 12, 10, 11, 3, 2, 0, 13, 9, 5, 4, 8, 15, 1, 6, 7] t = [] for i in xrange(4): for j in xrange(4): t.append(s[i][j]) for i in xrange(16): s[i/4][i%4] = t[r[i]] def mix_columns(self, s): wt = [3, 10, 8, 6] for i in range(4): s0 = xx(s[0][i],wt[0]) ^ xx(s[1][i],wt[1]) ^ xx(s[2][i],wt[2]) ^ xx(s[3][i],wt[3]) s1 = xx(s[0][i],wt[1]) ^ xx(s[1][i],wt[2]) ^ xx(s[2][i],wt[3]) ^ xx(s[3][i],wt[0]) s2 = xx(s[0][i],wt[2]) ^ xx(s[1][i],wt[3]) ^ xx(s[2][i],wt[0]) ^ xx(s[3][i],wt[1]) s3 = xx(s[0][i],wt[3]) ^ xx(s[1][i],wt[0]) ^ xx(s[2][i],wt[1]) ^ xx(s[3][i],wt[2]) s[0][i] = s0 s[1][i] = s1 s[2][i] = s2 s[3][i] = s3 def decrypt(self, plaintext): self.plain_state = text2matrix(plaintext) self.add_round_key(self.plain_state, self.round_keys[40:]) self._shift_rows(self.plain_state) self._sub_bytes(self.plain_state) for i in range(9, 0,-1): self.round_decrypt(self.plain_state, self.round_keys[4 * i: 4 * (i + 1)]) self.add_round_key(self.plain_state, self.round_keys[:4]) return matrix2text(self.plain_state) def _shift_rows(self, s): r = [14, 12, 10, 11, 3, 2, 0, 13, 9, 5, 4, 8, 15, 1, 6, 7] t = [] for i in xrange(4): for j in xrange(4): t.append(s[i][j]) for i in xrange(16): s[i/4][i%4] = t[r.index(i)] def _sub_bytes(self, s): for i in range(4): for j in range(4): s[i][j] = InvSbox[s[i][j]] def round_decrypt(self, state_matrix, key_matrix): self.add_round_key(state_matrix, key_matrix) self._mix_columns(state_matrix) self._shift_rows(state_matrix) self._sub_bytes(state_matrix) def _mix_columns(self, s): wt = [99, 214, 252, 197] for i in range(4): s0 = xx(s[0][i],wt[0]) ^ xx(s[1][i],wt[1]) ^ xx(s[2][i],wt[2]) ^ xx(s[3][i],wt[3]) s1 = xx(s[0][i],wt[1]) ^ xx(s[1][i],wt[2]) ^ xx(s[2][i],wt[3]) ^ xx(s[3][i],wt[0]) s2 = xx(s[0][i],wt[2]) ^ xx(s[1][i],wt[3]) ^ xx(s[2][i],wt[0]) ^ xx(s[3][i],wt[1]) s3 = xx(s[0][i],wt[3]) ^ xx(s[1][i],wt[0]) ^ xx(s[2][i],wt[1]) ^ xx(s[3][i],wt[2]) s[0][i] = s0 s[1][i] = s1 s[2][i] = s2 s[3][i] = s3 a = N1AES("THEAESPARTN1BOOK") #b = a.encrypt(flag[:16]) + a.encrypt(flag[16:]) b='588aa4c53819273bd2cdd6a20de7453ca21ef63d75077daa42b30e7fad50b39f' b=b.decode('hex') c=a.decrypt(b[:16])+a.decrypt(b[16:]) print(c)
[SWPU 2020]cbc1
题目
from Crypto.Cipher import AES import os flag = os.environ['FLAG'] BLOCKSIZE = 16 def pad(data): pad_len = BLOCKSIZE - (len(data) % BLOCKSIZE) if len(data) % BLOCKSIZE != 0 else 0 return data + "=" * pad_len def unpad(data): return data.replace("=","") def enc(data,key,iv): cipher = AES.new(key,AES.MODE_CBC,iv) encrypt = cipher.encrypt(pad(data)) return encrypt def dec(data,key,iv): try: cipher = AES.new(key,AES.MODE_CBC,iv) encrypt = cipher.decrypt(data) return unpad(encrypt) except: exit() def task(): try: key = os.urandom(16) iv = os.urandom(16) pre = "yusa"*4 for _ in range(3): choice = raw_input(menu) if choice == '1': name = raw_input("What's your name?") if name == 'admin': exit() token = enc(pre+name,key,iv) print "Here is your token(in hex): "+iv.encode('hex')+token.encode('hex') continue elif choice == '2': token = raw_input("Your token(in hex): ").decode('hex') iv = token[:16] name = dec(token[16:],key,iv) print iv.encode('hex')+name.encode('hex') if name[:16] == "yusa"*4: print "Hello, "+name[16:] if name[16:] == 'admin': print flag exit() else: continue except: exit() menu=''' 1. register 2. login 3. exit ''' if __name__ == "__main__": task()
m0=b'yusayusayusayusayusa'
m1=b'hhhhhhhhhhhhhhhhhhhh'
c0=E(m0^iv)
c1=E(m1^c0)
m1'=b'admin'=D(c1)^c0^m1^admin=m1^m1^admin
c0'=c0^m1^admin
D(c0')^iv=m'
m'^iv=D(c0')=>D(c0')^D(c0')^yusa*4=yusa*4
iv'=m'^yusa*4^iv
exp
from pwn import * from Crypto.Util.number import * re=remote("1.14.71.254",28645) re.recvuntil(b'3. exit') re.sendline(b'1') re.recvuntil(b"What's your name?") name='haha'*4 aa='yusa'*4 re.sendline(name.encode()) re.recvuntil(b'Here is your token(in hex): ') c=re.recvline().decode().strip() iv=c[:32] c0=c[32:64] c1=c[64:] re.recvuntil(b'3. exit') re.sendline(b'2') re.recvuntil(b'Your token(in hex): ') c00=int(c0,16)^bytes_to_long(name.encode())^bytes_to_long(b'===========admin') pl=iv+hex(c00)[2:] re.sendline(pl.encode()) mm=re.recvline().decode().strip()[32:] iv=hex(int(mm,16)^bytes_to_long(aa.encode())^int(iv,16))[2:] c=hex(c00)[2:]+c1 re.recvuntil(b'3. exit') re.sendline(b'2') re.recvuntil(b'Your token(in hex): ') p=iv+c re.sendline(p.encode()) re.interactive()
- 作者:Putao0v0
- 链接:https://tangly1024.com/article/n1AES
- 声明:本文采用 CC BY-NC-SA 4.0 许可协议,转载请注明出处。
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