Spencer McIntyre
131 lines
5.1 KiB
Python
131 lines
5.1 KiB
Python
import copy,struct,sys
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def chunks(lst, n):
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for i in range(0,len(lst),n):
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yield lst[i:i+n]
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def _cw(word):
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return(word[0]<<24)|(word[1]<<16)|(word[2]<<8)|word[3]
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def _s2b(text):
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return list(ord(c)for c in text)
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def _b2s(binary):
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return "".join(chr(b)for b in binary)
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if sys.version_info[0]>=3:
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xrange=range
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def _s2b(text):
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if isinstance(text,bytes):
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return text
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return[ord(c)for c in text]
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def _b2s(binary):
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return bytes(binary)
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else:
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bytes=lambda s,e:s
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def _gmul(a, b):
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r=0
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while b:
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if b&1: r^=a
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a<<=1
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if a>255: a^=0x11B
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b>>=1
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return r
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def _mix(n, vec):
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return sum(_gmul(n,v)<<(24-8*shift) for shift,v in enumerate(vec))
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def _ror32(n):
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return (n&255)<<24|n>>8
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def _rcon():
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return [_gmul(1, 1<<n) for n in range(30)]
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def _Si(S):
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return [S.index(n) for n in range(len(S))]
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def _mixl(S, vec):
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return [_mix(s, vec) for s in S]
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def _rorl(T):
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return [_ror32(t) for t in T]
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empty=struct.pack('')
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class AESCBC(object):
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nrs={16:10,24:12,32:14}
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rcon=_rcon()
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S=[99,124,119,123,242,107,111,197,48,1,103,43,254,215,171,118,202,130,201,125,250,89,71,240,173,212,162,175,156,164,114,192,183,253,147,38,54,63,247,204,52,165,229,241,113,216,49,21,4,199,35,195,24,150,5,154,7,18,128,226,235,39,178,117,9,131,44,26,27,110,90,160,82,59,214,179,41,227,47,132,83,209,0,237,32,252,177,91,106,203,190,57,74,76,88,207,208,239,170,251,67,77,51,133,69,249,2,127,80,60,159,168,81,163,64,143,146,157,56,245,188,182,218,33,16,255,243,210,205,12,19,236,95,151,68,23,196,167,126,61,100,93,25,115,96,129,79,220,34,42,144,136,70,238,184,20,222,94,11,219,224,50,58,10,73,6,36,92,194,211,172,98,145,149,228,121,231,200,55,109,141,213,78,169,108,86,244,234,101,122,174,8,186,120,37,46,28,166,180,198,232,221,116,31,75,189,139,138,112,62,181,102,72,3,246,14,97,53,87,185,134,193,29,158,225,248,152,17,105,217,142,148,155,30,135,233,206,85,40,223,140,161,137,13,191,230,66,104,65,153,45,15,176,84,187,22]
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Si=_Si(S)
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T1=_mixl(S, (2,1,1,3))
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T2=_rorl(T1)
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T3=_rorl(T2)
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T4=_rorl(T3)
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T5=_mixl(Si, (14,9,13,11))
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T6=_rorl(T5)
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T7=_rorl(T6)
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T8=_rorl(T7)
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U1=_mixl(range(256), (14,9,13,11))
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U2=_rorl(U1)
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U3=_rorl(U2)
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U4=_rorl(U3)
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def __init__(self,key):
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if len(key)not in(16,24,32):
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raise ValueError('Invalid key size')
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rds=self.nrs[len(key)];self._Ke=[[0]*4 for i in xrange(rds+1)];self._Kd=[[0]*4 for i in xrange(rds+1)];rnd_kc=(rds+1)*4;KC=len(key)//4;tk=[struct.unpack('>i',key[i:i+4])[0]for i in xrange(0,len(key),4)];rconpointer=0;t=KC
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for i in xrange(0,KC):
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self._Ke[i//4][i%4]=tk[i];self._Kd[rds-(i//4)][i%4]=tk[i]
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while t < rnd_kc:
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tt=tk[KC-1];tk[0]^=((self.S[(tt>>16)&255]<<24)^(self.S[(tt>>8)&255]<<16)^(self.S[tt&255]<<8)^self.S[(tt>>24)&255]^(self.rcon[rconpointer]<<24));rconpointer+=1
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if KC!=8:
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for i in xrange(1,KC):
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tk[i]^=tk[i-1]
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else:
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for i in xrange(1,KC//2):
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tk[i]^=tk[i-1]
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tt=tk[KC//2-1];tk[KC//2]^=(self.S[tt&255]^(self.S[(tt>>8)&255]<<8)^(self.S[(tt>>16)&255]<<16)^(self.S[(tt>>24)&255]<<24))
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for i in xrange(KC//2+1,KC):
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tk[i]^=tk[i-1]
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j=0
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while j<KC and t<rnd_kc:
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self._Ke[t//4][t%4]=tk[j];self._Kd[rds-(t//4)][t%4]=tk[j];j+=1;t+=1
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for r in xrange(1,rds):
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for j in xrange(0,4):
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tt=self._Kd[r][j];self._Kd[r][j]=(self.U1[(tt>>24)&255]^self.U2[(tt>>16)&255]^self.U3[(tt>>8)&255]^self.U4[tt&255])
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def _encdec(self,data,K,s,S,L1,L2,L3,L4):
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if len(data)!=16:
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raise ValueError('wrong block length')
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rds=len(K)-1;(s1,s2,s3)=s;a=[0,0,0,0];t=[(_cw(data[4*i:4*i+4])^K[0][i])for i in xrange(0,4)]
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for r in xrange(1,rds):
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for i in xrange(0,4):
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a[i]=(L1[(t[i]>>24)&255]^L2[(t[(i+s1)%4]>>16)&255]^L3[(t[(i+s2)%4]>>8)&255]^L4[t[(i+s3)%4]&255]^K[r][i])
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t=copy.copy(a)
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rst=[]
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for i in xrange(0,4):
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tt=K[rds][i];rst.append((S[(t[i]>>24)&255]^(tt>>24))&255);rst.append((S[(t[(i+s1)%4]>>16)&255]^(tt>>16))&255);rst.append((S[(t[(i+s2)%4]>>8)&255]^(tt>>8))&255);rst.append((S[t[(i+s3)%4]&255]^tt)&255)
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return rst
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def enc_in(self,pt):
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return self._encdec(pt,self._Ke,[1,2,3],self.S,self.T1,self.T2,self.T3,self.T4)
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def dec_in(self,ct):
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return self._encdec(ct,self._Kd,[3,2,1],self.Si,self.T5,self.T6,self.T7,self.T8)
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def pad(self,pt):
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c=16-(len(pt)%16)
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return pt+bytes(chr(c)*c,'utf-8')
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def unpad(self,pt):
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c=pt[-1]
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if type(c)!=int:
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c=ord(c)
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return pt[:-c]
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def encrypt(self,iv,pt):
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if len(iv)!=16:
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raise ValueError('initialization vector must be 16 bytes')
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else:
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self._lcb=_s2b(iv)
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pt=self.pad(pt)
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return empty.join([self.enc_b(b)for b in chunks(pt,16)])
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def enc_b(self,pt):
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if len(pt)!=16:
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raise ValueError('plaintext block must be 16 bytes')
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pt=_s2b(pt);pcb=[(p^l)for(p,l)in zip(pt,self._lcb)];self._lcb=self.enc_in(pcb)
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return _b2s(self._lcb)
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def decrypt(self,iv,ct):
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if len(iv)!=16:
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raise ValueError('initialization vector must be 16 bytes')
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else:
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self._lcb=_s2b(iv)
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if len(ct)%16!=0:
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raise ValueError('ciphertext must be a multiple of 16')
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return self.unpad(empty.join([self.dec_b(b)for b in chunks(ct,16)]))
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def dec_b(self,ct):
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if len(ct)!=16:
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raise ValueError('ciphertext block must be 16 bytes')
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cb=_s2b(ct);pt=[(p^l)for(p,l)in zip(self.dec_in(cb),self._lcb)];self._lcb=cb
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return _b2s(pt)
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