gotr: provide potr (rev f5551d6). now only depends on PyCrypto>=2.1

gotr/potr/utils.py

@@ -0,0 +1,65 @@
+#    Copyright 2012 Kjell Braden <afflux@pentabarf.de>
+#
+#    This file is part of the python-potr library.
+#
+#    python-potr is free software; you can redistribute it and/or modify
+#    it under the terms of the GNU Lesser General Public License as published by
+#    the Free Software Foundation; either version 3 of the License, or
+#    (at your option) any later version.
+#
+#    python-potr is distributed in the hope that it will be useful,
+#    but WITHOUT ANY WARRANTY; without even the implied warranty of
+#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#    GNU Lesser General Public License for more details.
+#
+#    You should have received a copy of the GNU Lesser General Public License
+#    along with this library.  If not, see <http://www.gnu.org/licenses/>.
+
+# some python3 compatibilty
+from __future__ import unicode_literals
+
+
+import struct
+
+def pack_mpi(n):
+    return pack_data(long_to_bytes(n))
+def read_mpi(data):
+    n, data = read_data(data)
+    return bytes_to_long(n), data
+def pack_data(data):
+    return struct.pack(b'!I', len(data)) + data
+def read_data(data):
+    datalen, data = unpack(b'!I', data)
+    return data[:datalen], data[datalen:]
+def unpack(fmt, buf):
+    s = struct.Struct(fmt)
+    return s.unpack(buf[:s.size]) + (buf[s.size:],)
+
+
+def bytes_to_long(b):
+    l = len(b)
+    s = 0
+    for i in range(l):
+        s += byte_to_long(b[i:i+1]) << 8*(l-i-1)
+    return s
+
+def long_to_bytes(l):
+    b = b''
+    while l != 0:
+        b = long_to_byte(l & 0xff) + b
+        l >>= 8
+    return b
+
+def byte_to_long(b):
+    return struct.unpack(b'B', b)[0]
+def long_to_byte(l):
+    return struct.pack(b'B', l)
+
+def human_hash(fp):
+    fp = fp.upper()
+    fplen = len(fp)
+    wordsize = fplen//5
+    buf = ''
+    for w in range(0, fplen, wordsize):
+        buf += '{0} '.format(fp[w:w+wordsize])
+    return buf.rstrip()