BUUCTF CRYPTO部分题目wp

对密码学了解不多，做一下熟悉熟悉

1，看我回旋踢

给的密文synt{5pq1004q-86n5-46q8-o720-oro5on0417r1}

简单的凯撒密码，用http://www.zjslove.com/3.decode/kaisa/index.html

得到flag

2,md5

密文：e00cf25ad42683b3df678c61f42c6bda

md5解密：https://www.cmd5.com

得到flag

3，url编码 

密文：%66%6c%61%67%7b%61%6e%64%20%31%3d%31%7d

用http://tool.chinaz.com/tools/urlencode.aspx

得到flag

4，摩丝

密文：.. .-.. --- ...- . -.-- --- ..-

用http://www.zuo114.com/mesm/

大写得到flag

5，变异凯撒

密文：afZ_r9VYfScOeO_UL^RWUc

格式：flag{}

根据格式，密文前五位ascii与格式相差为5，6，7，8，9，写脚本

m='afZ_r9VYfScOeO_UL^RWUc'
a=5
for i in range(0,len(m)):
    print(chr(ord(m[i])+a),end='')
    a+=1

  

6，Quoted-printable

密文：=E9=82=A3=E4=BD=A0=E4=B9=9F=E5=BE=88=E6=A3=92=E5=93=A6

用http://web.chacuo.net/charsetquotedprintable

解密得flag

7，password

打开文件

flag{zs19900315}

8,一眼就解密

密文：ZmxhZ3tUSEVfRkxBR19PRl9USElTX1NUUklOR30=

base64：http://tool.chinaz.com/Tools/Base64.aspx

解密得flag

9，丢失的MD5

送分题，给了一段python

import hashlib   
for i in range(32,127):
    for j in range(32,127):
        for k in range(32,127):
            m=hashlib.md5()
            m.update('TASC'+chr(i)+'O3RJMV'+chr(j)+'WDJKX'+chr(k)+'ZM')
            des=m.hexdigest()
            if 'e9032' in des and 'da' in des and '911513' in des:
                print des

 跑一遍得flag，大概是展示md5爆破

10，rabbit

密文：U2FsdGVkX1/+ydnDPowGbjjJXhZxm2MP2AgI

rabbit密码：http://tool.chinaz.com/Tools/TextEncrypt.aspx 

解密得flag

11，还原大师

md5爆破，写脚本

import hashlib
c='ABCDEFGHIJKLMNOPQRSTUVWXYZ'
a='e903???4dab????08?????51?80??8a?'
flag=0
def f(mds):
    for i in range(0,len(a)):
        if a[i]=='?':
            continue
        elif a[i]!=mds[i]:
            return 0
    return 1
for i in range(0,len(c)):
    if flag==1:
        break
    for j in range(0,len(c)):
        for k in range(0,len(c)):
            b='TASC'+c[i]+'O3RJMV'+c[j]+'WDJKX'+c[k]+'ZM'
            md=hashlib.md5(b.encode('utf8'))
            mds=md.hexdigest()
            flag=f(mds)
            if flag==1:
                print(mds)

得到flag 

12,权限获得第一步

给的文件：Administrator:500:806EDC27AA52E314AAD3B435B51404EE:F4AD50F57683D4260DFD48AA351A17A8:::

这好像是Linux的shadow文件，密码是F4AD50F57683D4260DFD48AA351A17A8

用https://www.cmd5.com 

得到flag

13，异性相吸

异或，给了两个文件，写脚本

with open('密文.txt' )as a:
    a=a.read()
with open('key.txt' )as b:
    b=b.read()
d=''
for i in range(0,len(b)):
    c=chr(ord(a[i])^ord(b[i]))
    d+=c
print(d)

 得到flag

14,window系统密码

给文件：

Administrator:500:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
ctf:1002:06af9108f2e1fecf144e2e8adef09efd:a7fcb22a88038f35a8f39d503e7f0062:::
Guest:501:aad3b435b51404eeaad3b435b51404ee:31d6cfe0d16ae931b73c59d7e0c089c0:::
SUPPORT_388945a0:1001:aad3b435b51404eeaad3b435b51404ee:bef14eee40dffbc345eeb3f58e290d56:::

和上面权限那题一样，密码：a7fcb22a88038f35a8f39d503e7f0062

解密得flag