serval-dna/nacl/nacl-20110221/crypto_secretbox/wrapper-open.cpp
Daniel O'Connor bf9710fd5a Unpacked nacl-20110221 after processing by nacl-prepare-sources.
This only affects build_android, if nacl-gcc-prep is run then build/`uname -s` will be created.
2012-02-27 12:40:14 +10:30

23 lines
974 B
C++

#include <string>
using std::string;
#include "crypto_secretbox.h"
string crypto_secretbox_open(const string &c,const string &n,const string &k)
{
if (k.size() != crypto_secretbox_KEYBYTES) throw "incorrect key length";
if (n.size() != crypto_secretbox_NONCEBYTES) throw "incorrect nonce length";
size_t clen = c.size() + crypto_secretbox_BOXZEROBYTES;
unsigned char cpad[clen];
for (int i = 0;i < crypto_secretbox_BOXZEROBYTES;++i) cpad[i] = 0;
for (int i = crypto_secretbox_BOXZEROBYTES;i < clen;++i) cpad[i] = c[i - crypto_secretbox_BOXZEROBYTES];
unsigned char mpad[clen];
if (crypto_secretbox_open(mpad,cpad,clen,(const unsigned char *) n.c_str(),(const unsigned char *) k.c_str()) != 0)
throw "ciphertext fails verification";
if (clen < crypto_secretbox_ZEROBYTES)
throw "ciphertext too short"; // should have been caught by _open
return string(
(char *) mpad + crypto_secretbox_ZEROBYTES,
clen - crypto_secretbox_ZEROBYTES
);
}