Adds missing auth module.

auth.nim

@@ -0,0 +1,60 @@
+import random, md5
+
+import bcrypt
+
+proc randomSalt(): string =
+  result = ""
+  for i in 0..127:
+    var r = rand(225)
+    if r >= 32 and r <= 126:
+      result.add(chr(rand(225)))
+
+proc devRandomSalt(): string =
+  when defined(posix):
+    result = ""
+    var f = open("/dev/urandom")
+    var randomBytes: array[0..127, char]
+    discard f.readBuffer(addr(randomBytes), 128)
+    for i in 0..127:
+      if ord(randomBytes[i]) >= 32 and ord(randomBytes[i]) <= 126:
+        result.add(randomBytes[i])
+    f.close()
+  else:
+    result = randomSalt()
+
+proc makeSalt*(): string =
+  ## Creates a salt using a cryptographically secure random number generator.
+  ##
+  ## Ensures that the resulting salt contains no ``\0``.
+  try:
+    result = devRandomSalt()
+  except IOError:
+    result = randomSalt()
+
+  var newResult = ""
+  for i in 0 ..< result.len:
+    if result[i] != '\0':
+      newResult.add result[i]
+  return newResult
+
+proc makePassword*(password, salt: string, comparingTo = ""): string =
+  ## Creates an MD5 hash by combining password and salt.
+  when defined(windows):
+    result = getMD5(salt & getMD5(password))
+  else:
+    let bcryptSalt = if comparingTo != "": comparingTo else: genSalt(8)
+    result = hash(getMD5(salt & getMD5(password)), bcryptSalt)
+
+proc makeIdentHash*(user, password, epoch, secret: string,
+                   comparingTo = ""): string =
+  ## Creates a hash verifying the identity of a user. Used for password reset
+  ## links and email activation links.
+  ## If ``epoch`` is smaller than the epoch of the user's last login then
+  ## the link is invalid.
+  ## The ``secret`` is the 'salt' field in the ``person`` table.
+  echo(user, password, epoch, secret)
+  when defined(windows):
+    result = getMD5(user & password & epoch & secret)
+  else:
+    let bcryptSalt = if comparingTo != "": comparingTo else: genSalt(8)
+    result = hash(user & password & epoch & secret, bcryptSalt)