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I want to decrypt my C++ Openssl RSA message with node-rsa.

In node-rsa I get

Error: Error during decryption (probably incorrect key). Original error: Error: Incorrect data or key

Encryption:

//ADD PRIVATE KEY
const char* mKey = "...";

BIO* bo = BIO_new(BIO_s_mem());

BIO_write(bo, mKey, strlen(mKey));

EVP_PKEY* pKey = 0;
PEM_read_bio_PrivateKey(bo, &pKey, 0, 0);

BIO_free(bo);

RSA* keypair = EVP_PKEY_get1_RSA(pKey);

char msg[2048 / 8] = "Hallo Welt!";
std::cout << "Message to encrypt: " << msg << std::endl;


//ENCRYPT
char* encrypt = (char*)malloc(RSA_size(keypair));
int encrypt_len;

if ((encrypt_len = RSA_public_encrypt(strlen(msg) + 1, (unsigned char*)msg, (unsigned char*)encrypt, keypair, RSA_PKCS1_PADDING)) == -1) {
    std::cout << "ERROR";
}

std::cout << "ENCRYPTED: " << std::endl;
std::cout << base64_encode(encrypt);
std::cout << std::endl;

Result:

Message to encrypt: Hallo Welt!
ENCRYPTED:
xR00Ei3kxS4SYJfBlGX8IPyyBbOAnAOqwfdKtzJNs4JsKo/5g1IhCesY0YETyJX9S48uWNWHr5C3IAGu2+0N0qdi8WDs+m+oX/F1I7H5/n8pQcwqGn81mhSe6cYpBFHdX2GgzuJ8tNr3HsigorA=

Now the node-rsa code which doesn't work:

const NodeRSA = require('node-rsa');

const key = new NodeRSA(...);

key.setOptions({encryptionScheme: 'pkcs1'});

const text = key.decrypt("xR00Ei3kxS4SYJfBlGX8IPyyBbOAnAOqwfdKtzJNs4JsKo/5g1IhCesY0YETyJX9S48uWNWHr5C3IAGu2+0N0qdi8WDs+m+oX/F1I7H5/n8pQcwqGn81mhSe6cYpBFHdX2GgzuJ8tNr3HsigorA=", 'utf8');

console.log(text);

Used Key:

-----BEGIN RSA PRIVATE KEY-----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-----END RSA PRIVATE KEY-----

I don't understand what I am doeing wrong. Is it possible to de/encrypt with these different systems?

Improve this question
5
  • You use a 2048 bit = 256 bytes key, i.e. the ciphertext should also be 256 bytes long. But it has Base64 decoded only a length of 110 bytes. So there seems to be a problem with the encryption. Commented Feb 27, 2021 at 14:58
  • That could be but I also tried it to decrypt it as a "normal text" from a text-file with the openssl bash. Didn't worked... I've also encrypted and decrypted it with the bash and the node-rsa library. That worked perfectly! Only C++ is doeing something different. Commented Feb 27, 2021 at 16:27
  • @Topaco but now as you say it. In the bash I get "data greater than mod len" Commented Feb 27, 2021 at 16:42
  • According to this error message your plaintext is longer than the allowed length. With RSA and PKCS#1 v1.5 padding, for a 2048 bits = 256 bytes key the maximum allowed plaintext length is 245 bytes, here. For longer messages hybrid encryption is applied. Commented Feb 27, 2021 at 17:07
  • @Topaco But my message isn't so long. I have a 1024 bit private key and my plaintext is "Hallo Welt!"... And the en/decryption is working with the bash and node-rsa. I am slowly despairing... Commented Feb 27, 2021 at 21:45
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