Various security fixes

Security updates

• Additional check when Ks mismatch in savedata and sortedID in #156
• Do not normalize IDs of Shamir's Secret Sharing by @pdyraga in #155
• Check paillier ciphertext in #151
• Bugfix for vss, check shareid when construct vss in #149
• Check length of bits of NTildej by @yycen in #146
• dlog smallgroup 8 by @ackratos in #115

Other updates

• Updated protobuf dependency and fixed type clash by @PlamenHristov in #141
• cherry pick > curve as parameter (#137) by @FitzLu in #139
• fix R and S may not be 32 bytes by @ackratos in #130
• S in eddsa signature is not encoded correctly by @ackratos in #122