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/* tell python that PyArg_ParseTuple(t#) means Py_ssize_t, not int */
#define PY_SSIZE_T_CLEAN
#include <Python.h>
#if (PY_VERSION_HEX < 0x02050000)
typedef int Py_ssize_t;
#endif
/* This is required for compatibility with Python 2. */
#if PY_MAJOR_VERSION >= 3
#include <bytesobject.h>
#define y "y"
#else
#define PyBytes_FromStringAndSize PyString_FromStringAndSize
#define y "t"
#endif
int curve25519_sign(unsigned char* signature_out,
const unsigned char* curve25519_privkey,
const unsigned char* msg, const unsigned long msg_len,
const unsigned char* random);
int curve25519_verify(const unsigned char* signature,
const unsigned char* curve25519_pubkey,
const unsigned char* msg, const unsigned long msg_len);
int curve25519_donna(char *mypublic,
const char *secret, const char *basepoint);
static PyObject *
calculateSignature(PyObject *self, PyObject *args)
{
const char *random;
const char *privatekey;
const char *message;
char signature[64];
Py_ssize_t randomlen, privatekeylen, messagelen;
if (!PyArg_ParseTuple(args, y"#"y"#"y"#:generate",&random, &randomlen, &privatekey, &privatekeylen, &message, &messagelen))
return NULL;
if (privatekeylen != 32) {
PyErr_SetString(PyExc_ValueError, "private key must be 32-byte string" );
return NULL;
}
if (randomlen != 64) {
PyErr_SetString(PyExc_ValueError, "random must be 64-byte string");
return NULL;
}
curve25519_sign((unsigned char *)signature, (unsigned char *)privatekey,
(unsigned char *)message, messagelen, (unsigned char *)random);
return PyBytes_FromStringAndSize((char *)signature, 64);
}
static PyObject *
verifySignature(PyObject *self, PyObject *args)
{
const char *publickey;
const char *message;
const char *signature;
Py_ssize_t publickeylen, messagelen, signaturelen;
if (!PyArg_ParseTuple(args, y"#"y"#"y"#:generate", &publickey, &publickeylen, &message, &messagelen, &signature, &signaturelen))
return NULL;
if (publickeylen != 32) {
PyErr_SetString(PyExc_ValueError, "publickey must be 32-byte string");
return NULL;
}
if (signaturelen != 64) {
PyErr_SetString(PyExc_ValueError, "signature must be 64-byte string");
return NULL;
}
int result = curve25519_verify((unsigned char *)signature, (unsigned char *)publickey,
(unsigned char *)message, messagelen);
return Py_BuildValue("i", result);
}
static PyObject *
generatePrivateKey(PyObject *self, PyObject *args)
{
char *random;
Py_ssize_t randomlen;
if(!PyArg_ParseTuple(args, y"#:clamp", &random, &randomlen)) {
return NULL;
}
if(randomlen != 32) {
PyErr_SetString(PyExc_ValueError, "random must be 32-byte string");
return NULL;
}
random[0] &= 248;
random[31] &= 127;
random[31] |= 64;
return PyBytes_FromStringAndSize((char *)random, 32);
}
static PyObject *
generatePublicKey(PyObject *self, PyObject *args)
{
const char *private;
char mypublic[32];
char basepoint[32] = {9};
Py_ssize_t privatelen;
if (!PyArg_ParseTuple(args, y"#:makepublic", &private, &privatelen))
return NULL;
if (privatelen != 32) {
PyErr_SetString(PyExc_ValueError, "input must be 32-byte string");
return NULL;
}
curve25519_donna(mypublic, private, basepoint);
return PyBytes_FromStringAndSize((char *)mypublic, 32);
}
static PyObject *
calculateAgreement(PyObject *self, PyObject *args)
{
const char *myprivate, *theirpublic;
char shared_key[32];
Py_ssize_t myprivatelen, theirpubliclen;
if (!PyArg_ParseTuple(args, y"#"y"#:generate",
&myprivate, &myprivatelen, &theirpublic, &theirpubliclen))
return NULL;
if (myprivatelen != 32) {
PyErr_SetString(PyExc_ValueError, "input must be 32-byte string");
return NULL;
}
if (theirpubliclen != 32) {
PyErr_SetString(PyExc_ValueError, "input must be 32-byte string");
return NULL;
}
curve25519_donna(shared_key, myprivate, theirpublic);
return PyBytes_FromStringAndSize((char *)shared_key, 32);
}
static PyMethodDef
curve25519_functions[] = {
{"calculateSignature", calculateSignature, METH_VARARGS, "random+privatekey+message->signature"},
{"verifySignature", verifySignature, METH_VARARGS, "publickey+message+signature->valid"},
{"generatePrivateKey", generatePrivateKey, METH_VARARGS, "data->private"},
{"generatePublicKey", generatePublicKey, METH_VARARGS, "private->public"},
{"calculateAgreement", calculateAgreement, METH_VARARGS, "private+public->shared"},
{NULL, NULL, 0, NULL},
};
#if PY_MAJOR_VERSION >= 3
static struct PyModuleDef
curve25519_module = {
PyModuleDef_HEAD_INIT,
"axolotl_curve25519",
NULL,
0,
curve25519_functions,
};
PyObject *
PyInit_axolotl_curve25519(void)
{
return PyModule_Create(&curve25519_module);
}
#else
PyMODINIT_FUNC
initaxolotl_curve25519(void)
{
(void)Py_InitModule("axolotl_curve25519", curve25519_functions);
}
#endif
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