SPAKE2-C

Implementation of SPAKE2 protocol in C, fully compatible with the BoringSSL implementation.

Get Started

If you have make installed, you can easily install the library in Linux or macOS by running

make install

or, to build a shared/dynamic library in Linux/macOS/Windows:

make build

In the latter case, you have to copy or add the contents of the ./include/ directory to your include path as well as add the shared library in the library path.

After installing the library, you can simply import <spake2/spake2.h>.

// Create alice (client) and bob (server)
struct spake2_ctx_st *alice = SPAKE2_CTX_new(spake2_role_alice, kClientName, sizeof(kClientName), kServerName, sizeof(kServerName));
struct spake2_ctx_st *bob = SPAKE2_CTX_new(spake2_role_bob, kServerName, sizeof(kServerName), kClientName, sizeof(kClientName));
// TODO: Check if any of them returns NULL, and if so, fail operation

// The fields below are kept for compatibility with BoringSSL (if you use them)
// alice->disable_password_scalar_hack = (char) 1;
// bob->disable_password_scalar_hack = (char) 1;

// Generate message from password
int statusAlice = SPAKE2_generate_msg(alice, aMessage, &aMsgSize, SPAKE2_MAX_MSG_SIZE, kPassword, sizeof(kPassword));
int statusBob = SPAKE2_generate_msg(bob, bMessage, &bMsgSize, SPAKE2_MAX_MSG_SIZE, kPassword, sizeof(kPassword));
// TODO: Check if the status is 1 (success) or fail operation

// Get key from message
statusAlice = SPAKE2_process_msg(alice, aKey, &aKeyLen, sizeof(aKey), (uint8_t *) bMessage, bMsgSize);
statusBob = SPAKE2_process_msg(bob, bKey, &bKeyLen, sizeof(bKey), (uint8_t *) aMessage, aMsgSize);
// TODO: Check if the status is 1 (success) or fail operation

// At this point, aKey and bKey should be the same.

C++ wrapper

Coming soon.

Licenses

Portions of this library is available under the terms of Apache-2.0 license, LGPL-2.1 and MIT license. The library itself is licensed under LGPL-3.0 or later.

SHA512 library is the only LGPL dependency. If you know a better SHA512 implementation than glibc's, feel free to share it. I am willing to adopt a permissive license instead of LGPL.