Spencer McIntyre
58 lines
1.2 KiB
Python
58 lines
1.2 KiB
Python
import sys,math,random,binascii as ba,os
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from struct import unpack as u
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from struct import pack
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is2 = sys.version_info[0]<3
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def bt(b):
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if is2:
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return b
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return ord(b)
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def b2i(b):
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return int(ba.b2a_hex(b),16)
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def i2b(i):
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h='%x'%i
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if len(h)%2==1:
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h ='0'+h
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if not is2:
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h=h.encode('utf-8')
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return ba.a2b_hex(h)
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def rs(a,o):
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if a[o]==bt(pack('B',0x81)):
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return(u('B',a[o+1])[0],2+o)
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elif a[o] == bt(pack('B',0x82)):
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return(u('>H',a[o+1:o+3])[0],3+o)
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def ri(b,o):
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i,o =rs(b,o)
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return(b[o:o+i],o+i)
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def b2me(b):
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if b[0]!=bt(pack('B',0x30)):
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return(None,None)
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_,o=rs(b,1)
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if b[o]!=bt(pack('B',2)):
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return(None,None)
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(m,o)=ri(b,o+1)
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if b[o]!=bt(pack('B',2)):
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return(None,None)
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e=b[o+2:]
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return(b2i(m),b2i(e))
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def der2me(d):
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if d[0]!=bt(pack('B',0x30)):
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return(None,None)
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_,o=rs(d,1)
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while o<len(d):
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if d[o]==bt(pack('B',0x30)):
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o+=u('B',d[o+1:o+2])[0]
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elif d[o]==bt(pack('B',0x05)):
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o+=2
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elif d[o]==bt(pack('B',0x03)):
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_,o=rs(d,o+1)
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return b2me(d[o+1:])
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else:
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return(None,None)
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def rsa_enc(der,msg):
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m,e=der2me(der)
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h=pack('BB',0,2)
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d=pack('B',0)
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l=256-len(h)-len(msg)-len(d)
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p=os.urandom(512).replace(pack('B',0),pack(''))
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return i2b(pow(b2i(h+p[:l]+d+msg),e,m))
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