Encrypt in Java (AES), Decrypt in C++ (OpenSSL)

Question

All,

I'm trying to encrypt a string in Java using AES 256 and decrypt it in C++ using openssl. In java I:

Generated a SecretKey in a JCEKS
Encrypted the string
encoded both the string and getEncoded() from the SecretKey in base64

Now I'm trying to decrypt it in C++ using OpenSSL:

string encoded = string("LtANvfmnb5zj+4+g6I7hC53eHMIRa4BOkzMpXYLlA9DRnRWjQjO9uMot6hR7zzTIOtdmkRJ16aVZRfIT3sYn17jYEJjvAN9/N7FbblLplCtOuHatGffH0pSf8lu76SUzDIZU+EXgTnK1SsEa4sndcXvg5jaElxr4GCHq+F2aL7t+LVjbqWg4kpYkYbKdrKQgOsMCbBBG2aMFTmQ/cxnVyH8juC/ZTSrPMyjZ7KxS0P9PzfmxkeSi3VsBIjXL6Q4pneZeemP+1JdG02yQWhruJUuH5aRE0piQ776lxt6g0wU=");
string encodedKey = string("1rE2AM4Xf0ItxN/s1oDvaNmXhXlVF3hE+vSkyMPzDl4=");

string decodedEnc = base64_decode(encoded);
string decodedKey = base64_decode(encodedKey);

const unsigned char *keyBytes = reinterpret_cast<const unsigned char*>(decodedKey.c_str());
const unsigned char *in = reinterpret_cast<const unsigned char*>(decodedEnc.c_str());



cout << "initializing" << endl;
AES_KEY key;
/* set the encryption key */
AES_set_encrypt_key(keyBytes, 256, &key);

unsigned char *out = (unsigned char*) malloc(1024);

cout << "Decrypting" << endl;

AES_ecb_encrypt(in,out,&key,AES_DECRYPT);

cout << "decrypted " << out << endl;
char* dec = reinterpret_cast< char*>(out);

string decrypted = std::string(dec);

cout << "Decrypted String : '" << decrypted << "'" << endl;

All I am getting is garbage printed to the terminal. I feel like I'm close, so any help would be greatly appreciated.

Thanks Marc

Orochi Orochi · Accepted Answer · 2011-05-12T12:40:31

according to my understanding, try the decryption key and then AES_decrypt which should be called as follows:

cout << "Decrypting" << endl;

from this line onwards... use the code as follows:

AES_KEY k
AES_set_decrypt_key(keyBytes, 256, &k);

unsigned char* outdecrypt = new unsigned char[1024];
AES_decrypt(out, outdecrypt, &k);

Encrypt in Java (AES), Decrypt in C++ (OpenSSL)

3 Answers