³ò ~ñĴDc@sndZdefd„ƒYZd„Zd„Zd„Zd„Zd„Zd„Zd „Z d d d „Z d S( s„Implementation of GCM (Galois/Counter Mode). See http://csrc.nist.gov/ CryptoToolkit/modes/proposedmodes/gcm/gcm-revised-spec.pdf .tObjectcBseZd„ZRS(cOs.||_x|D]}||i|iq~ƒS(s:Convert a block (list of integer bytes) to a long integer.ii(tsumt enumeratetlen(tblockR RR ((s*/home/ping/web/passpet/darcs/server/gcm.pyttolongscCs=g}t|ddddƒD]}|t||?ƒq~S(s:Convert a long integer to a block (list of integer bytes).iiĝ˙˙˙(RR(tlongt blockbytesR tshift((s*/home/ping/web/passpet/darcs/server/gcm.pyttoblock"sc Csnx&t|ƒ|djo|d7}qWg}tdt|ƒ|ƒD]!}|tt||||!ƒqF~S(sBConvert a string to a list of blocks (a block is a list of bytes).it(RRtmaptord(tdataR!R R((s*/home/ping/web/passpet/darcs/server/gcm.pyttoblocks&scCs:dig}|D]}|ditt|ƒƒq~ƒS(s%Convert a list of blocks to a string.t(tjoinR%tchr(tblocksR R((s*/home/ping/web/passpet/darcs/server/gcm.pyttostring-scs ˆidjotdƒ‚n|d joB|d jotdƒ‚ntˆit|ˆiƒƒƒ}n|d }tˆitddƒƒƒ‰t|d>dBdƒ‰‡‡fd†‰‡fd †‰‡‡‡‡fd †}‡‡‡‡fd †}t||ƒS(sŬCreate a Galois/Counter Mode object with the given cipher. Supply a 96-bit long integer for the 'iv' argument or a single block as a long integer for the 'nonce' argument (which will be used to generate the IV). The resulting object has a method encrypt() that takes a string and yields an encrypted string concatenated with a 16-byte MAC, and a method decrypt() that takes an encrypted string with a 16-byte MAC suffix and yields the decrypted string.is)GCM requires a cipher with 128-bit blockss either iv or nonce must be givenii`ii cs~ˆ}g}x[t|dƒD]J}|d tt|dƒddƒ}|it|ˆi|ƒƒƒqWt|ƒt|ƒ S(Niiü˙˙˙ii(R(R#RtappendRtencipherR-R(R'Rt newblocksR(tciphertY0(s*/home/ping/web/passpet/darcs/server/gcm.pyt transformEs%#csTd}x0t|dƒD]}t|t|ƒAˆƒ}qWt|t|ƒdAˆƒS(Niii(R(RRR(R'RR(tH(s*/home/ping/web/passpet/darcs/server/gcm.pytghashMs csGˆ|ƒ}ˆ|ƒtˆiˆƒƒA}|tt|dƒgƒfS(Ni(RR/R-R#(R'tCtT(R3R1R2R5(s*/home/ping/web/passpet/darcs/server/gcm.pytencryptSs csUttt|ƒƒ}ˆ|ƒtˆiˆƒƒA|jotdƒ‚nˆ|ƒS(Ns#invalid message authentication code(RR%R&R/t ValueError(R'tmacR7(R3R1R2R5(s*/home/ping/web/passpet/darcs/server/gcm.pytdecryptXs&Nl@(R!t TypeErrortNoneRR/R#R(R1tivtnonceR8R;((R3R4R1R2R5s*/home/ping/web/passpet/darcs/server/gcm.pytGCM1s   % N( t__doc__tobjectRRRRRR#R(R-R=R@(((s*/home/ping/web/passpet/darcs/server/gcm.pyss