Add crypto_scrypt to the Python script package

scrypt.diff

diff -ru scrypt-0.5.3/src/scrypt2.c scrypt-mod/src/scrypt2.c
--- scrypt-0.5.3/src/scrypt2.c	2011-02-19 06:56:07.000000000 -0800
+++ scrypt-mod/src/scrypt2.c	2012-05-12 01:19:06.933753937 -0700
@@ -27,6 +27,7 @@
 #include <Python.h>
 
 #include "scryptenc/scryptenc.h"
+#include "crypto/crypto_scrypt.h"
 
 static PyObject *ScryptError;
 
@@ -139,11 +140,74 @@
     return value;
 }
 
+static PyObject *scrypt_hash(PyObject *self, PyObject *args, PyObject* kwargs) {
+    PyStringObject *password,   *salt;
+    size_t          passwordlen, saltlen;
+    int paramerror, hasherror;
+    uint64_t N = 1 << 14;
+    uint32_t r = 8;
+    uint32_t p = 1;
+    uint8_t *outbuf;
+    size_t   outbuflen;
+
+    static char *g2_kwlist[] = {"password", "salt", "N", "r", "p", NULL};
+
+    // note, this assumes uint32_t is unsigned long (k)
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "SS|Kkk", g2_kwlist,
+                                                    &password, &salt,
+                                                    &N, &r, &p)) {
+        return NULL;
+    }
+
+    Py_INCREF(password);
+    Py_INCREF(salt);
+
+    passwordlen = PyString_Size((PyObject*) password);
+    saltlen = PyString_Size((PyObject*) salt);
+
+    // note, output buffer must be less than (2^32-1) * 32
+    outbuf = PyMem_Malloc(64);
+    outbuflen = 64;
+
+    Py_BEGIN_ALLOW_THREADS;
+
+    if ( r * p >= (1 << 30) || N <= 1 || (N & (N-1)) != 0) {
+        paramerror = -1;
+    } else {
+        paramerror = 0;
+        hasherror = crypto_scrypt((uint8_t *) PyString_AsString((PyObject *) password), passwordlen,
+                                  (uint8_t *) PyString_AsString((PyObject *) salt),     saltlen,
+                                  N, r, p,
+                                  outbuf, outbuflen);
+    }
+   
+    Py_END_ALLOW_THREADS;
+
+    Py_DECREF(password);
+    Py_DECREF(salt);
+
+    PyObject *value = NULL;
+    if (paramerror != 0) {
+        PyErr_Format(ScryptError, "%s",
+            "hash parameters are wrong (r*p should be < 2**30, and N should be a power of two > 1)");
+    } else {
+        if (hasherror != 0) {
+            PyErr_Format(ScryptError, "%s", "could not compute hash");
+        } else {
+            value = Py_BuildValue("z#", outbuf, outbuflen);
+        }
+    }
+    PyMem_Free(outbuf);
+    return value;
+}
+
 static PyMethodDef ScryptMethods[] = {
     { "encrypt", (PyCFunction) scrypt_encrypt, METH_VARARGS | METH_KEYWORDS,
 			"encrypt(input, password, maxtime=300, maxmem=0, maxmemfrac=0.5): str; encrypt a string" },
     { "decrypt", (PyCFunction) scrypt_decrypt, METH_VARARGS | METH_KEYWORDS,
 			"decrypt(input, password, maxtime=300, maxmem=0, maxmemfrac=0.5): str; decrypt a string" },
+    { "hash", (PyCFunction) scrypt_hash, METH_VARARGS | METH_KEYWORDS,
+			"hash(password, salt, N=2**14, r=8, p=1): str; compute a 64-byte scrypt hash" },
     { NULL, NULL, 0, NULL }
 };