From aa5365666bb17299035a3d857bcce962004bda1e Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Thu, 6 Oct 2016 20:21:16 +0200
Subject: Base64 and import/export keys

---
 rsa.cpp | 65 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 59 insertions(+), 6 deletions(-)

(limited to 'rsa.cpp')

diff --git a/rsa.cpp b/rsa.cpp
index 11bf0eb..ec79e72 100644
--- a/rsa.cpp
+++ b/rsa.cpp
@@ -1,12 +1,65 @@
+#include <cstdint>
 #include <cassert>
+#include "base64.h"
 #include "numalgo.h"
+#include "primes.h"
+#include "rng.h"
 #include "rsa.h"
 
-Bigint encrypt(const PublicKey &pubkey,Bigint msg){
-	assert(msg>1&&msg<pubkey.mod);
-	return expmod(msg,pubkey.exp,pubkey.mod);
-}
+using namespace std;
+
+namespace RSA{
+
+	Bigint encrypt(const PublicKey &pubkey,Bigint msg){
+		assert(msg>1&&msg<pubkey.mod);
+		return expmod(msg,pubkey.exp,pubkey.mod);
+	}
+
+	Bigint decrypt(const PrivateKey &privkey,Bigint encr){
+		return expmod(encr,privkey.pexp,privkey.pub.mod);
+	}
+
+	PrivateKey genkey(int nbits,Rng &rng){
+		pair<Bigint,Bigint> pq=genprimepair(rng,nbits);
+		PrivateKey key;
+		key.pub.mod=pq.first*pq.second;
+		key.pub.exp=65537;
+		Bigint x;
+		egcd((pq.first-Bigint::one)*(pq.second-Bigint::one),key.pub.exp,x,key.pexp);
+		return key;
+	}
+
+	PrivateKey genkey(int nbits){
+		Arc4Rng rng;
+		return genkey(nbits,rng);
+	}
+
+	PrivateKey genkey(int nbits,const string &password){
+		KeyRng rng(password);
+		return genkey(nbits,rng);
+	}
+
+	pair<string,string> exportkey(const PrivateKey &key){
+		string modser=key.pub.mod.serialiseMantissa();
+		int32_t modlen=modser.size();
+		string modlenstr{(char)(modlen&0xff),(char)((modlen>>8)&0xff),(char)((modlen>>16)&0xff),(char)((modlen>>24)&0xff)};
+		return make_pair(
+			Base64::encode(modlenstr + modser + key.pub.exp.serialiseMantissa()),
+			Base64::encode(modlenstr + modser + key.pexp.serialiseMantissa()));
+	}
+
+	PrivateKey importkey(const string &pub,const string &priv){
+		string pubdeser=Base64::decode(pub);
+		assert(pubdeser.size()>4);
+		int modlen=(unsigned char)(pubdeser[0])+(unsigned char)(pubdeser[1]<<8)+
+		           (unsigned char)(pubdeser[2]<<16)+(unsigned char)(pubdeser[3]<<24);
+		assert((int)pubdeser.size()-4>modlen);
+		PrivateKey key;
+		key.pub.mod.deserialiseMantissa(string(pubdeser.begin()+4,pubdeser.begin()+(4+modlen)));
+		key.pub.exp.deserialiseMantissa(string(pubdeser.begin()+(4+modlen),pubdeser.end()));
+		string privdeser=Base64::decode(priv);
+		key.pexp.deserialiseMantissa(string(privdeser.begin()+(4+modlen),privdeser.end()));
+		return key;
+	}
 
-Bigint decrypt(const PrivateKey &privkey,Bigint encr){
-	return expmod(encr,privkey.pexp,privkey.pub.mod);
 }
-- 
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