cryptopp base64 trailing 0x0a

Question

I'm using CryptoPP to encode a string "abc", the problem is the encoded base64 string always has a trailing '0x0a'? here's my code:

#include <iostream>
#include <string>

using namespace std;

#include "crypto/base64.h"
using namespace CryptoPP;

int main() {
string in("abc");

string encoded;

CryptoPP::StringSource ss(
    in,
    true, 
    new CryptoPP::Base64Encoder(
        new CryptoPP::StringSink(encoded)
    )
);

cout << encoded.length() << endl;// outputs 5, should be 4
cout << encoded;
}

the string "abc" should be encoded to "YWJj", but the result is YWJj\n, (\n == 0x0a), and the length is 5 .

Changing the source string doesn't help, any string will be encrypted with a trailing \n Why is that? Thanks

Answer 1

From the Base64Encoder docs, the signature of the constructor is

Base64Encoder (BufferedTransformation *attachment=NULL,
               bool insertLineBreaks=true,
               int maxLineLength=72)

So you get line breaks by default in your encoded string. To avoid this, just do:

CryptoPP::StringSource ss(
    in,
    true, 
    new CryptoPP::Base64Encoder(
        new CryptoPP::StringSink(encoded),
        false
    )
);