* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at https://mozilla.org/MPL/2.0/.
*
* (c) ZeroTier, Inc.
* https://www.zerotier.com/
*/
* This file defines the elliptic curve crypto used for ZeroTier V1. The normal
* public version uses C25519 and Ed25519, while the FIPS version uses NIST.
* FIPS builds are completely incompatible with regular ZeroTier, but that's
* fine since FIPS users typically want a fully isolated private network. If you
* are not such a user you probably don't want this.
*/
#ifndef ZT_ECC_HPP
#define ZT_ECC_HPP
#include "Utils.hpp"
#ifdef ZT_FIPS
#include <openssl/bn.h>
#include <openssl/ec.h>
#include <openssl/err.h>
#include <openssl/evp.h>
#include <openssl/pem.h>
#define ZT_ECC_EPHEMERAL_PUBLIC_KEY_LEN 97
#define ZT_ECC_PUBLIC_KEY_SET_LEN (97 * 2)
#define ZT_ECC_PRIVATE_KEY_SET_LEN (48 * 2)
#define ZT_ECC_SIGNATURE_LEN 96
class ECC {
public:
struct Public {
uint8_t data[ZT_ECC_PUBLIC_KEY_SET_LEN];
};
struct Private {
uint8_t data[ZT_ECC_PRIVATE_KEY_SET_LEN];
};
struct Signature {
uint8_t data[ZT_ECC_SIGNATURE_LEN];
};
struct Pair {
Public pub;
Private priv;
};
};
#else
namespace ZeroTier {
#define ZT_ECC_EPHEMERAL_PUBLIC_KEY_LEN 32
#define ZT_ECC_PUBLIC_KEY_SET_LEN 64
#define ZT_ECC_PRIVATE_KEY_SET_LEN 64
#define ZT_ECC_SIGNATURE_LEN 96
class ECC {
public:
struct Public {
uint8_t data[ZT_ECC_PUBLIC_KEY_SET_LEN];
};
struct Private {
uint8_t data[ZT_ECC_PRIVATE_KEY_SET_LEN];
};
struct Signature {
uint8_t data[ZT_ECC_SIGNATURE_LEN];
};
struct Pair {
Public pub;
Private priv;
};
* Generate an elliptic curve key pair
*/
static inline Pair generate()
{
Pair kp;
Utils::getSecureRandom(kp.priv.data, ZT_ECC_PRIVATE_KEY_SET_LEN);
_calcPubDH(kp);
_calcPubED(kp);
return kp;
}
* Generate a key pair satisfying a condition
*
* This begins with a random keypair from a random secret key and then
* iteratively increments the random secret until cond(kp) returns true.
* This is used to compute key pairs in which the public key, its hash
* or some other aspect of it satisfies some condition, such as for a
* hashcash criteria.
*
* @param cond Condition function or function object
* @return Key pair where cond(kp) returns true
* @tparam F Type of 'cond'
*/
template <typename F> static inline Pair generateSatisfying(F cond)
{
Pair kp;
void* const priv = (void*)kp.priv.data;
Utils::getSecureRandom(priv, ZT_ECC_PRIVATE_KEY_SET_LEN);
_calcPubED(kp);
do {
++(((uint64_t*)priv)[1]);
--(((uint64_t*)priv)[2]);
_calcPubDH(kp);
} while (! cond(kp));
return kp;
}
* Perform C25519 ECC key agreement
*
* Actual key bytes are generated from one or more SHA-512 digests of
* the raw result of key agreement.
*
* @param mine My private key
* @param their Their public key
* @param keybuf Buffer to fill
* @param keylen Number of key bytes to generate
*/
static void agree(const Private& mine, const Public& their, void* keybuf, unsigned int keylen);
static inline void agree(const Pair& mine, const Public& their, void* keybuf, unsigned int keylen)
{
agree(mine.priv, their, keybuf, keylen);
}
* Sign a message with a sender's key pair
*
* This takes the SHA-521 of msg[] and then signs the first 32 bytes of this
* digest, returning it and the 64-byte ed25519 signature in signature[].
* This results in a signature that verifies both the signer's authenticity
* and the integrity of the message.
*
* This is based on the original ed25519 code from NaCl and the SUPERCOP
* cipher benchmark suite, but with the modification that it always
* produces a signature of fixed 96-byte length based on the hash of an
* arbitrary-length message.
*
* @param myPrivate My private key
* @param myPublic My public key
* @param msg Message to sign
* @param len Length of message in bytes
* @param signature Buffer to fill with signature -- MUST be 96 bytes in length
*/
static void sign(const Private& myPrivate, const Public& myPublic, const void* msg, unsigned int len, void* signature);
static inline void sign(const Pair& mine, const void* msg, unsigned int len, void* signature)
{
sign(mine.priv, mine.pub, msg, len, signature);
}
* Sign a message with a sender's key pair
*
* @param myPrivate My private key
* @param myPublic My public key
* @param msg Message to sign
* @param len Length of message in bytes
* @return Signature
*/
static inline Signature sign(const Private& myPrivate, const Public& myPublic, const void* msg, unsigned int len)
{
Signature sig;
sign(myPrivate, myPublic, msg, len, sig.data);
return sig;
}
static inline Signature sign(const Pair& mine, const void* msg, unsigned int len)
{
Signature sig;
sign(mine.priv, mine.pub, msg, len, sig.data);
return sig;
}
* Verify a message's signature
*
* @param their Public key to verify against
* @param msg Message to verify signature integrity against
* @param len Length of message in bytes
* @param signature 96-byte signature
* @return True if signature is valid and the message is authentic and unmodified
*/
static bool verify(const Public& their, const void* msg, unsigned int len, const void* signature);
* Verify a message's signature
*
* @param their Public key to verify against
* @param msg Message to verify signature integrity against
* @param len Length of message in bytes
* @param signature 96-byte signature
* @return True if signature is valid and the message is authentic and unmodified
*/
static inline bool verify(const Public& their, const void* msg, unsigned int len, const Signature& signature)
{
return verify(their, msg, len, signature.data);
}
private:
static void _calcPubDH(Pair& kp);
static void _calcPubED(Pair& kp);
};
}
#endif
#endif