# shop-js encrypted message decoder in Python # Copyright John Hanna (c) 2002 under the terms of the GPL # see http://shop-js.sf.net for details and latest version # modified 7/12/2002 # Of course to run this you'll need python from python.org or elsewhere # this is expecting private key parts as generated by the shop-js RSA key generator # you'll obviously want to replace these values with YOUR OWN private key values # privateKey=[ [d],[p],[q] ] privateKey=[ [211146173,236796389,99054011,39430498,107502635,22100528,173332685,126067633,23490737,43112374,215603654,97763768,129307240,193500832,225995383,196217318,247811242,95758361,147], [79930095,201216333,170018212,115859736,10404795,32150654,210660423,132599055,204635034,14], [47716471,908384,204231222,108648834,118784602,25920125,261301885,215145545,83985924,11]] # if you want a test phrase, decode this: # aXCFtURf_XY1L2SUxHGfR"E5FAeq9E"OeFmfl7WlNO5It131"noEcl81_UxP # BMN6siYz7M_B"vE4boCaLGzajxQhLrgyw37TGofQC2v5QYnLJfxpqWDlPgSy # J6QCBZtKde5_jbIwgC5ipn42WgU6 debug=1 successPage="http://www.yoursite.com/success.html" # or wherever you want -- see the bottom of this script import cgi def rc4(key, string): """Return string rc4 (de/en)crypted with RC4.""" s,i,j,klen=range(256),0,0,len(key) for i in range(256): j=(ord(key[i%klen])+s[i]+j)%256 s[i],s[j]=s[j],s[i] for i in range(256): j=(ord(key[i%klen])+s[i]+j)%256 s[i],s[j]=s[j],s[i] r='' for i in range(len(string)): i2=i % 256 j=(s[i2]+j)%256 s[i2],s[j]=s[j],s[i2] r+=chr(ord(string[i])^s[(s[i2]+s[j])%256]) return r def inverse(x, n): """Return the mod n inverse of x.""" y, a, b = n, 1, 0 while y>0: x, (q, y) = y, divmod(x, y) a, b = b, a - b*q if a < 0: a = a + n assert x==1, "No inverse, GCD is %d" % x return a def crt_RSA(m, d, p, q): """ Compute m**d mod p*q for RSA private key operations.""" xp = pow(m % p, d%(p-1), p) xq = pow(m % q, d%(q-1), q) t = ((xq - xp) * inverse(p, q)) % q if t < 0: t = t + q return t * p + xp b64s='abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_"' def base64ToText(text): r,m,a,c='',0,0,0 for i in text[:]: c=b64s.find(i) if(c >= 0) : if(m): r += chr((c << (8-m))& 255 | a) a = c >> m m+=2 if(m==8):m=0 return r def t2b(s): r=0L m=1L for i in s[:]: r+=m*ord(i) m*=256L return r def b2t(b): r='' while(b): r+=chr(b % 256) b>>=8 return r def fix(a): r=0L s=0 for i in a[:]: r|=long(i) << s s+=28 return r def rsaDecode(key,text): """ decode the text based on the given rsa key. """ # separate the session key from the text text=base64ToText(text) sessionKeyLength=ord(text[0]) sessionKeyEncryptedText=text[1:sessionKeyLength+1] text=text[sessionKeyLength+1:] sessionKeyEncrypted=t2b(sessionKeyEncryptedText) # un-rsa the session key sessionkey=crt_RSA(sessionKeyEncrypted,fix(key[0]),fix(key[1]),fix(key[2])) sessionkey=b2t(sessionkey) text=rc4(sessionkey,text) return text if debug: print "Content-type: text/html" print print "Decryptor" print "

Decrypting message

" form=cgi.FieldStorage() if not form.has_key('message') : print "Error: no message field found in submitted form

" else: m=form['message'].value print "Your message was

"
     print rsaDecode(privateKey, m)
     print "
" print "
" print "complete...

" else: form=cgi.FieldStorage() if form.has_key('message') : message=rsaDecode(privateKey, form['message'].value) # your processing goes here -- log in your secure database or whatever... print "Location: "+successPage else: # no message was passed -- report the error print "Content-type: text/html" print print "Decryptor Error" print "

Error Decrypting message

" print "Please report this message to your webmaster" print ""