upgrade python bindings to use a recent stable version of cryptopp

[dawuud]

use more recent stable version of cryptopp

[dawuud]

using the cryptopp maintainer's git repo git@…:weidai11/cryptopp.git
copied sources files from tagged branch CRYPTOPP_5_6_3;
however pycryptopp doesn't build because of errors like these

x86_64-linux-gnu-gcc -pthread -DNDEBUG -g -fwrapv -O2 -Wall -Wstrict-prototypes -fno-strict-aliasing -Wdate-time -D_FORTIFY_SOURCE=2 -g -fstack-protector-strong -Wformat -Werror=format-security -fPIC -DCRYPTOPP_DISABLE_ASM=1 -I. -I/usr/include/python2.7 -c src-cryptopp/casts.cpp -o build/temp.linux-x86_64-2.7/src-cryptopp/casts.o -w
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
In file included from src-cryptopp/seckey.h:16:0,
                 from src-cryptopp/cast.h:9,
                 from src-cryptopp/casts.cpp:2:
src-cryptopp/cryptlib.h: In member function ‘virtual void CryptoPP::SimpleKeyingInterface::Resynchronize(const byte*, int)’:
src-cryptopp/cryptlib.h:593:21: error: ‘CRYPTOPP_UNUSED’ was not declared in this scope
   CRYPTOPP_UNUSED(iv); CRYPTOPP_UNUSED(ivLength);
                     ^
src-cryptopp/cryptlib.h: In member function ‘void CryptoPP::SimpleKeyingInterface::AssertValidKeyLength(size_t) const’:
src-cryptopp/cryptlib.h:655:26: error: ‘CRYPTOPP_UNUSED’ was not declared in this scope
   {CRYPTOPP_UNUSED(length); assert(IsValidKeyLength(length));}
                          ^

[dawuud]

i got the build working. i replaced config.h with config.recommend

​https://github.com/tahoe-lafs/pycryptopp/pull/29

[dawuud]

this is the latest crypto++ from upstream master... it builds and tests fine but not additional functionality was added:
​https://github.com/tahoe-lafs/pycryptopp/pull/30

[dawuud]

here's the latest
​https://github.com/tahoe-lafs/pycryptopp/pull/32

adds cryptopp 5.6.5

all tests pass.

[daira]

We are upgrading to fix ​https://www.cvedetails.com/cve/CVE-2016-7420/ .