Bugfixes and debugging

1 files changed, 45 insertions, 15 deletions

diff --git a/envelope.cpp b/envelope.cpp
index 5270dae..c881815 100644
--- a/envelope.cpp
+++ b/envelope.cpp
@@ -1,9 +1,12 @@
+#include <stdexcept>
 #include <cassert>
 #include "aes.h"
 #include "base64.h" //TODO: remove
 #include "envelope.h"
 #include "rng.h"
 
+#undef DEBUG
+
 using namespace std;
 
 namespace Envelope{
@@ -24,28 +27,39 @@ namespace Envelope{
 		do {
 			for(int i=0;i<keylen;i++)*(uint32_t*)&aeskey[4*i]=crng.get();
 		} while(!safeKey(aeskey));
-		// cerr<<"decrkey="<<Base64::encode(aeskey)<<endl;
+#ifdef DEBUG
+		cerr<<"decrkey="<<Base64::encode(aeskey)<<endl;
+#endif
 		
 		string payload(AES::encrypt(data,aeskey,AES::AES_256_CBC));
-		// cerr<<"payload="<<Base64::encode(payload)<<endl;
+#ifdef DEBUG
+		cerr<<"payload="<<Base64::encode(payload)<<endl;
+#endif
 		Bigint rsadata;
 		for(int i=0;i<(int)aeskey.size();i++){
 			if(i!=0)rsadata<<=8;
 			rsadata+=(uint8_t)aeskey[i];
 		}
-		// cerr<<"rsadata="<<rsadata<<endl;
+#ifdef DEBUG
+		cerr<<"rsadata="<<rsadata<<endl;
+		cerr<<"pubkey = {"<<pubkey.mod<<" , "<<pubkey.exp<<'}'<<endl;
+#endif
 		Bigint res(RSA::encrypt(rsadata,pubkey));
-		// cerr<<"rsaencr="<<res<<endl;
+#ifdef DEBUG
+		cerr<<"rsaencr="<<res<<endl;
+#endif
 
-		vector<uint8_t> bytes; //bytes in little-endian order
+		vector<uint8_t> bytes; //bytes in little-endian order (so, reverse!)
 		while(res!=0){
 			bytes.push_back(res.lowdigits()&0xff);
 			res>>=8;
 		}
-		// cerr<<"encrkey="<<Base64::encode(string(bytes.rbegin(),bytes.rend()))<<endl;
+#ifdef DEBUG
+		cerr<<"encrkey="<<Base64::encode(string(bytes.rbegin(),bytes.rend()))<<endl;
+#endif
 
 		payload.reserve(payload.size()+bytes.size()+2);
-		for(int i=bytes.size()-1;i>=0;i--)payload.push_back(bytes[i]); //append in big-endian order
+		for(int i=bytes.size()-1;i>=0;i--)payload.push_back(bytes[i]); //append in big-endian order again
 		payload.push_back(bytes.size()>>8);
 		payload.push_back((uint8_t)bytes.size()&0xff);
 
@@ -53,38 +67,54 @@ namespace Envelope{
 	}
 
 	string decrypt(const string &data,const RSA::Key &privkey){
-		// cerr<<"=== DECRYPT ==="<<endl;
+#ifdef DEBUG
+		cerr<<"=== DECRYPT ==="<<endl;
+#endif
 		if(data.size()<2)throw invalid_argument("Envelope data length invalid");
 		int encrkeylen=((uint16_t)(uint8_t)data[data.size()-2]<<8)+(uint8_t)data.back();
 		assert(encrkeylen<(1<<16));
-		// cerr<<"encrkeylen="<<encrkeylen<<endl;
+#ifdef DEBUG
+		cerr<<"encrkeylen="<<encrkeylen<<endl;
+#endif
 		if((int)data.size()<encrkeylen+2)throw invalid_argument("Envelope key format invalid");
 
 		string encrkey(encrkeylen,'\0'); //in big-endian
 		for(int i=0;i<encrkeylen;i++){
 			encrkey[i]=data[data.size()-2-encrkeylen+i];
 		}
-		// cerr<<"encrkey="<<Base64::encode(encrkey)<<endl;
+#ifdef DEBUG
+		cerr<<"encrkey="<<Base64::encode(encrkey)<<endl;
+#endif
 
 		Bigint rsadata;
 		for(int i=0;i<encrkeylen;i++){
 			if(i!=0)rsadata<<=8;
 			rsadata+=(uint8_t)encrkey[i];
 		}
-		// cerr<<"rsaencr="<<rsadata<<endl;
+#ifdef DEBUG
+		cerr<<"rsaencr="<<rsadata<<endl;
+		cerr<<"privkey = {"<<privkey.mod<<" , "<<privkey.exp<<'}'<<endl;
+#endif
 		Bigint res(RSA::decrypt(rsadata,privkey));
-		// cerr<<"rsadata="<<res<<endl;
+#ifdef DEBUG
+		cerr<<"rsadata="<<res<<endl;
+#endif
 
 		vector<uint8_t> bytes; //bytes in little-endian order
-		while(res!=0){
+		for(int i=0;i<32;i++){ //32 is the number of bytes in a 256-bit AES key (256/8=32)
 			bytes.push_back(res.lowdigits()&0xff);
 			res>>=8;
 		}
+		assert(res==0);
 		string decrkey(bytes.size(),'\0');
 		for(int i=0;i<(int)bytes.size();i++)decrkey[bytes.size()-1-i]=bytes[i];
-		// cerr<<"decrkey="<<Base64::encode(decrkey)<<endl;
+#ifdef DEBUG
+		cerr<<"decrkey="<<Base64::encode(decrkey)<<endl;
+#endif
 
-		// cerr<<"payload="<<Base64::encode(data.substr(0,data.size()-2-encrkeylen))<<endl;
+#ifdef DEBUG
+		cerr<<"payload="<<Base64::encode(data.substr(0,data.size()-2-encrkeylen))<<endl;
+#endif
 		return AES::decrypt(data.substr(0,data.size()-2-encrkeylen),decrkey,AES::AES_256_CBC);
 	}