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diff --git a/python/vyos/snmpv3_hashgen.py b/python/vyos/snmpv3_hashgen.py
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+++ b/python/vyos/snmpv3_hashgen.py
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+# Copyright 2020 VyOS maintainers and contributors <maintainers@vyos.io>
+#
+# This library 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 2.1 of the License, or (at your option) any later version.
+#
+# This library 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/>.
+
+# Documentation / Inspiration
+# - https://tools.ietf.org/html/rfc3414#appendix-A.3
+# - https://github.com/TheMysteriousX/SNMPv3-Hash-Generator
+
+key_length = 1048576
+
+def random(l):
+    # os.urandom(8) returns 8 bytes of random data
+    import os
+    from binascii import hexlify
+    return hexlify(os.urandom(l)).decode('utf-8')
+
+def expand(s, l):
+    """ repead input string (s) as long as we reach the desired length in bytes """
+    from itertools import repeat
+    reps = l // len(s) + 1 # approximation; worst case: overrun = l + len(s)
+    return ''.join(list(repeat(s, reps)))[:l].encode('utf-8')
+
+def plaintext_to_md5(passphrase, engine):
+    """ Convert input plaintext passphrase to MD5 hashed version usable by net-snmp """
+    from hashlib import md5
+    tmp = expand(passphrase, key_length)
+    hash = md5(tmp).digest()
+    engine = bytearray.fromhex(engine)
+    out = b''.join([hash, engine, hash])
+    return md5(out).digest().hex()
+
+def plaintext_to_sha1(passphrase, engine):
+    """ Convert input plaintext passphrase to SHA1hashed version usable by net-snmp """
+    from hashlib import sha1
+    tmp = expand(passphrase, key_length)
+    hash = sha1(tmp).digest()
+    engine = bytearray.fromhex(engine)
+    out = b''.join([hash, engine, hash])
+    return sha1(out).digest().hex()