I am generating ECDSA Prime256 keypair using OpenSSL with C++ and trying to import the hex version of the public key using Java. I pass the byte array I obtain from C++ to the following function in java which expects the byte array to be in an X.509 encoded format.
public static PublicKey getPublicKey(byte[] pk) throws NoSuchAlgorithmException, InvalidKeySpecException {
EncodedKeySpec publicKeySpec = new X509EncodedKeySpec(pk);
KeyFactory kf = KeyFactory.getInstance(Constant.KEY_FACTORY_TYPE);
PublicKey pub = kf.generatePublic(publicKeySpec);
return pub;
}
I create an elliptic curve key pair using the following function which retuns an EC_KEY*
EC_KEY* generate_keypair() {
EC_KEY *eckey = EC_KEY_new();
EC_GROUP *ecgroup = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
EC_KEY_set_group(eckey, ecgroup);
EC_KEY_set_asn1_flag(eckey, OPENSSL_EC_NAMED_CURVE);
int kpGenerationStatus = EC_KEY_generate_key(eckey);
if (kpGenerationStatus) {
return eckey;
}
return nullptr;
}
Given the keypair returned by the function above, I want to export the public key to an ASN1.DER format which can be imported using the java method above.
I convert the public key which is of type EC_POINT* to its hex form using EC_POINT_point2hex() by doing the following:
EC_GROUP *ecgroup = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
EC_KEY *keypair = generate_keypair();
char *result = NULL;
BN_CTX *ctx;
ctx = BN_CTX_new();
const EC_POINT *pub = EC_KEY_get0_public_key(keypair);
result = EC_POINT_point2hex(ecgroup, pub, POINT_CONVERSION_UNCOMPRESSED, ctx);
printf("%s\n", result);
Which return the following:
04F588CD1D7103A993D47E53D58C3F40BE8F570604CF2EA01A7657C1423EB19C51BC379F0BEE1FAA60BB9A07DE73EA9BEF7709C1C6429D4051B44F73A458FFB80D
When I inspect this with the ASN.1 decoder I see a message which says Length over 48 bits not supported at position 1 and trying to import it using the java method I receive an error as follows:
java.security.spec.InvalidKeySpecException: java.security.InvalidKeyException: IOException: DerInputStream.getLength(): Should use short form for length
Is there something I am missing while exporting the public key from EC_POINT* to a X.509 Encoded hex string that I can import for validating any signatures?
You are going in the incorrect direction as you want ASN1 base64 value.
EC_POINT_point2hex is converting the internal public key value to hex. It's not in ASN1 format.
You can produce what you want from the command line like so:
Generate EC private key:
openssl ecparam -name prime256v1 -genkey -noout -out key.pem
Extra public key in DER(ASN1) format:
openssl ec -in key.pem -pubout -outform der -out public.cer
Convert to base64
openssl base64 -in .\public.cer
If you take that output and paste it into ASN.1 decoder link it works fine.
Now to turn this into code, you have the EC key generation, but what you want is the steps to:
Generate ASN1 formatted public key
Convert it to base64
To generate the ASN1 formatted public key you want to use the i2d_EC_PUBKEY set of methods and then convert to base64 using BIO_f_base64 filter.
So here is an example problem that when I copy the output to ASN.1 decoder link it works fine.
#include <openssl/bio.h>
#include <openssl/ec.h>
#include <openssl/evp.h>
#include <openssl/x509.h>
EC_KEY* generate_keypair() {
EC_KEY *eckey = EC_KEY_new();
EC_GROUP *ecgroup = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
EC_KEY_set_group(eckey, ecgroup);
EC_KEY_set_asn1_flag(eckey, OPENSSL_EC_NAMED_CURVE);
int kpGenerationStatus = EC_KEY_generate_key(eckey);
if (kpGenerationStatus) {
return eckey;
}
return nullptr;
}
int main()
{
EC_GROUP *ecgroup = EC_GROUP_new_by_curve_name(NID_X9_62_prime256v1);
EC_KEY *keypair = generate_keypair();
BIO* out = BIO_new(BIO_s_mem());
BIO* b64 = BIO_new(BIO_f_base64());
BIO_push(b64, out);
i2d_EC_PUBKEY_bio(b64, keypair);
BIO_flush(b64);
// do what you want this the output in out memory BIO
char* p;
long length = BIO_get_mem_data(out, &p);
// ensure null terminated but copying the buffer into a string to output...
puts(std::string(p, length).c_str());
BIO_free_all(out);
}
I can't complete on the Java side, but if it works with the manual openssl generated base64 string then it will work with the sample application.
I need to store certificates and their private key in memory.
Certificates can be in the 4 following formats : PEM, PKCS12, PKCS7, DER.
I'ill need to write them back as PEM later.
All the snippets i see are storing only the public certificate in a X509 struct.
What about the private part ??
I've found a way using X509_INFO, but i got a major problem with it :
I haven't find a way to get a X509_INFO from DER/PKCS7/PKCS12 files
For the moment i got the following code :
QList<X509_INFO*>* Certificat::stringPEMToX509_INFO(QString stringPem)
{
QList <X509_INFO*>* liste_certificats = new QList<X509_INFO*>;
STACK_OF(X509_INFO)* pile_certificats = NULL;
X509_INFO* certificat;
BIO* bio = BIO_new(BIO_s_mem());
const char* pem = stringPem.toAscii().constData();
BIO_puts(bio, pem);
//https://github.com/openssl/openssl/blob/master/crypto/pem/pem_info.c
pile_certificats = PEM_X509_INFO_read_bio(bio, NULL, NULL, NULL);
for (int i = 0; i < sk_X509_INFO_num(pile_certificats); i++)
{
certificat = sk_X509_INFO_value(pile_certificats, i);
liste_certificats->push_back(certificat);
}
sk_X509_INFO_pop_free(pile_certificats, X509_INFO_free);
BIO_free_all(bio);
return liste_certificats;
}
My goal would be to have the same function but for DER, PKCS12 and PKCS7.
I tried to get a X509_INFO from a DER like this :
p12 = d2i_PKCS12_bio(bio, NULL);
certificat = X509_INFO_new();
certificat->x509 = cert;
certificat->x_pkey = pkey;
But x_pkey is a X509_PKEY and pkey an EVP_PKEY...
If there is no way to store it as a single struct, would it be possible to store my certificates as X509 + a EVP_PKEY for the private key, and still output both private and public part in a PEM ?
PKCS7 is only meant for public keys. DER and PEM are simply ways of encoding a PKCS (and many other) objects. Since you want to store everything into a single structure, you would probably most benefit from PKCS12. OpenSSL provides functions to parse PKCS12 data and get both the cert and key out of it.
I have to send some encrypted data throught the network (websocket)
I generated a key pair with the the following node.js module :
https://github.com/juliangruber/keypair
My public key looks like this:
-----BEGIN RSA PUBLIC KEY-----
MIIBCgKCAQEAlUiMDQsBgj5P/T86w/eg9MXUj8M4WMVihP8YzmDxMqCFb7D+w4N/1XcxWxQT
....
Wo+SRCsr6npfp1ctDhMtkXIeNT4lKf3qUGhP5tbx/TreaNF/d8zCeinGR/KeBGadMwIDAQAB
-----END RSA PUBLIC KEY-----
In the C++ code, I generated a RSA class with read the public key via a char*
const char rsaKey1[] = "-----BEGIN RSA PUBLIC KEY-----\n"
"MIIBCgKCAQEAlUiMDQsBgj5P/T86w/eg9MXUj8M4WMVihP8YzmDxMqCFb7D+w4N/1XcxWxQT\n"
....
"Wo+SRCsr6npfp1ctDhMtkXIeNT4lKf3qUGhP5tbx/TreaNF/d8zCeinGR/KeBGadMwIDAQAB\n"
"-----END RSA PUBLIC KEY-----\n";
BIO* bio = BIO_new_mem_buf( rsaKey1, strlen(rsaKey1));
m_rsaPubKey = PEM_read_bio_RSAPublicKey(bio, NULL, NULL, NULL);
usigned the m_rsaPubKey , I have able to generate a std::vector of unsigned char with encrypted data
std::vector<u8> Rsa::encrypt(std::string & msg)
{
std::vector<u8> encryptedData;
char *encrypt = new char[RSA_size(m_rsaPubKey)];
int encryptLen;
if (encryptLen = RSA_public_encrypt(msg.size() + 1, (unsigned
char*)msg.c_str(), (unsigned char*)encrypt, m_rsaPubKey,
RSA_PKCS1_OAEP_PADDING) == -1)
{
LogOutSys("error encoding string");
}
for (u32 i = 0; i < strlen(encrypt); i++)
{
encryptedData.push_back(encrypt[i]);
}
delete encrypt;
return encryptedData;
}
I don't get any errors while reading the public key or encrypting my data so I assume the encryption went ok.
then the data went throught a websocket and is received with node.js
the private key is read like this:
var rsa = new RSA(fs.readFileSync("./rsa-keys/sj_private_1.pem"),
{encryptionScheme :'pkcs8'})
and decoding
var decrypted = rsa.decrypt(data)
where data is a buffer of same length and content (no corruption while sending via the websocket)
c++ side:
encrypted len 256, first bytes 117 125 58 109
node size :
Buffer(256) [117, 125, 58, 109, 38, 229, 7, 189, …]
the rsa.decrypt generated an exception :
TypeError: Cannot read property 'length' of null
I tried several encryptionScheme option (including the default , but always getting the same error or Incorrect key or data
Because of the random padding in OAEP, troubleshooting encryption issues with it can sometimes be a bit tricky.
For further troubleshooting use the following checklist to shoot down potential issues:
Make sure you use the same crypto mechanism on both ends. In your C++ code you are using RSA_PKCS1_OAEP_PADDING but the JavaScript lines in your question does not tell what mechanism you use there.
Make sure that the mechanisms are implemented the same ways in both C++ and Node libraries. It is crucial you have the same hashing method and MGF1 (mask generation function) in both implementations. This is one of the most typical failing points that I've seen in my career.
Since you are working with byte arrays, make sure you are not having any issues in the byte order. In other words, make sure both ends talks the same language in regard of endianness (For self-study: https://www.cs.umd.edu/class/sum2003/cmsc311/Notes/Data/endian.html).
In my C++ program I created a public/private key pair using CryptoAPI.
CryptGenKey(eTokenProv,ENCRYPT_ALGORITHM,CRYPT_EXPORTABLE,&k1)
Keys are stored in a eToken.
Is it possible to get the public key using PKCS#11? The private key previously created is found after a search using the following search-template:
CK_ATTRIBUTE private_search[] = {
{CKA_PRIVATE, CK_TRUE, sizeof(CK_BBOOL)}
};
If I set CKA_PRIVATE to CK_FALSE, I can't get the public key. I also tried with other attributes.
Is there a way to do it?
EDIT
As owlstead suggests, I tried to create a public key starting from the modulus and public exponent of a key created in a previous session (in CAPI or, just for this test, in PKCS11). I got the modulus and public exponent from a private key in these buffers:
CK_BYTE modulus[128]; //if 1024bit
CK_BYTE publicExponent[4]; //4 Byte, according to public key blob
But when I try to create a new public with key with the following instructions:
CK_ATTRIBUTE publicKeyTemplate[] = {
{CKA_TOKEN, &yes, sizeof(true)},
{CKA_WRAP, &yes, sizeof(true)},
{CKA_ENCRYPT, &yes, sizeof(true)},
{CKA_MODULUS_BITS, &modulusBits, sizeof(modulusBits)},
{CKA_MODULUS, &modulus, sizeof(modulus)},
{CKA_PUBLIC_EXPONENT, &publicExponent, sizeof(publicExponent)}
CK_MECHANISM mechanism = {CKM_RSA_PKCS_KEY_PAIR_GEN, NULL_PTR, 0 };
rv = (*functions->C_GenerateKeyPair) (session, &mechanism, publicKeyTemplate, 6, privateKeyTemplate, 6, &hPublicKey, &hPrivateKey);
I get the error "Invalid template". The probles is the modulus, because, without it, I can create a key pair. I use the function C_GenerateKeyPair, but I'm only interested in the public key. I omitted the private template.
What is the wrong here?
CKA_PRIVATE does not indicate a private key at all.
When the CKA_PRIVATE attribute is TRUE, a user may not access the object until the user
has been authenticated to the token
Instead you should look for an attribute such as CKA_CLASS with a value CKO_PUBLIC_KEY or CKO_PRIVATE_KEY, possibly using other attributes to filter your results further.
If you cannot find any CKO_PUBLIC_KEY then I presume it was either not generated in the token (key was imported, check if CKA_LOCAL is set). Alternatively, it may have only been created as a session object. Finally it may have been removed.
Note that RSA private keys commonly do contain the public exponent, so you can still construct a public key from just the private key object (using the modulus and public exponent, of course).
Remove the reference symbol in CK_ATTRIBUTE when setting a pointer to a CK_BYTE array - in your case modulus.
CK_ATTRIBUTE publicKeyTemplate[] = {
{CKA_TOKEN, &yes, sizeof(true)},
{CKA_WRAP, &yes, sizeof(true)},
{CKA_ENCRYPT, &yes, sizeof(true)},
{CKA_MODULUS_BITS, &modulusBits, sizeof(modulusBits)},
{CKA_MODULUS, modulus, sizeof(modulus)},
{CKA_PUBLIC_EXPONENT, &publicExponent, sizeof(publicExponent)}
I haven't tested your code, but I am able to successfully obtain modulus of an CK_OBJECT_HANDLE (private key / public key) by setting following template and making a call to C_GetAttributeValue:
CK_BYTE modulus[128];
CK_ATTRIBUTE Modulus = { CKA_MODULUS, modulus, sizeof(modulus) };
if ((rv = (*p11FunctionList->C_GetAttributeValue)(hSession, hPrivKey /*hPubKey*/, &Modulus, 1)) == CKR_OK)
{
// do something with obtained modulus
}
The generated private-public key pair was generated as follow:
CK_OBJECT_HANDLE hPrivKey, hPubKey;
CK_BBOOL bTrue = TRUE;
CK_ULONG mod_bits = 1024;
CK_MECHANISM GenMechanism = { CKM_RSA_PKCS_KEY_PAIR_GEN, NULL_PTR, 0 };
CK_ATTRIBUTE GenPubTemplate[] = {
{ CKA_MODULUS_BITS, &mod_bits, sizeof(CK_ULONG) },
{ CKA_PUBLIC_EXPONENT, "\x01\x00\x01", 3 },
{ CKA_TOKEN, &bTrue, sizeof(CK_BBOOL) },
{ CKA_ID, (CK_CHAR_PTR)szKeyID, strlen(szKeyID) } }; // szKeyID is a const char *
CK_ATTRIBUTE GenPrivTemplate[] = {
{ CKA_TOKEN, &bTrue, sizeof(CK_BBOOL) },
{ CKA_PRIVATE, &bTrue, sizeof(CK_BBOOL) },
{ CKA_SENSITIVE, &bTrue, sizeof(CK_BBOOL) },
{ CKA_ID, (CK_CHAR_PTR)szKeyID, strlen(szKeyID) } }; // szKeyID is a const char *
// hSession is a CK_SESSION_HANDLE of an opened & logged in session
if ((rv = (*p11FunctionList->C_GenerateKeyPair)(hSession, &GenMechanism, GenPubTemplate, 4, GenPrivTemplate, 4, &hPubKey, &hPrivKey)) == CKR_OK)
{
// Now get the modulus of a the private / public key as described above
}
Though this has already been answered for others who want to do this we have created a PKCS#11 based wrapper for CryptoAPI, you can find it here:
https://github.com/PeculiarVentures/pvpkcs11
With this you can access keys stored in CryptoAPI as well as certificates using the native PKCS#11 interfaces.
What I'm trying to do is generate random RSA keys and then store them before my program terminates. This part is working just fine using RSA_generate_key, PEM_write_bio_RSAPrivateKey and PEM_write_bio_RSA_PUBKEY. I can also encrypt/decrypt just find using the RSA structure returned by RSA_generate_key.
However, my problem comes when my program restarts and I want to read back in the keys that I stored previously. I can use PEM_read_bio_RSAPrivateKey and PEM_read_bio_RSA_PUBKEY to pull the keys in, but I need to get them into the same RSA structure, similar to how they are stored by RSA_generate_key.
My code is shown below. I have the keys stored in memory along with a small header that tell me how large the keys are. The private key start right after the header and the public key is stored right after the private key.
privateKey = (uint8_t *) ( buffer + rsaStruct->hdrSize );
publicKey = (uint8_t *) ( privateKey + rsaStruct->privateKeyLength );
bioPrivate = BIO_new_mem_buf( (void *) privateKey, rsaStruct->privateKeyLength );
bioPublic = BIO_new_mem_buf( (void *) publicKey, rsaStruct->publicKeyLength );
bioPrivate = BIO_new_mem_buf( (void *) privateKey, rsaStruct->privateKeyLength + rsaStruct->publicKeyLength );
if( bioPrivate == NULL || bioPublic == NULL ) {
fprintf( stderr, "%s: BIO_new_mem_buf failed!\n", __FUNCTION__ );
return ECE_RSA_ERROR_BIO_CREATION_FAILED;
}
PEM_read_bio_RSAPrivateKey( bioPrivate, &keyPair, NULL, NULL );
PEM_read_bio_RSA_PUBKEY( bioPublic, &keyPair, NULL, NULL );
BIO_free( bioPrivate );
BIO_free( bioPublic );
If I try to just send in the same RSA structure, it doesn't seem to work. I'm able to encrypt just fine, but my decryption fails. This could likely be due to the fact that the public key is the last key retrieve and the one used for encryption. If the second call over-writes the address of my RSA struct, I would end up with an RSA structure that has nothing but the public key.
Anyway, if anyone could tell me how to get both the public and private key into the same RSA structure, that would be great!
Comparing to RSA private key, public key additionaly contains only the public exponent. So just copy it from public key to private key structure, and everything should work.