diff --git a/mmgen/contrib/__init__.py b/mmgen/contrib/__init__.py
new file mode 100755
index 00000000..e69de29b
diff --git a/mmgen/base_proto/bitcoin/bech32.py b/mmgen/contrib/bech32.py
similarity index 100%
rename from mmgen/base_proto/bitcoin/bech32.py
rename to mmgen/contrib/bech32.py
diff --git a/mmgen/ed25519.py b/mmgen/contrib/ed25519.py
similarity index 100%
rename from mmgen/ed25519.py
rename to mmgen/contrib/ed25519.py
diff --git a/mmgen/ed25519ll_djbec.py b/mmgen/contrib/ed25519ll_djbec.py
similarity index 100%
rename from mmgen/ed25519ll_djbec.py
rename to mmgen/contrib/ed25519ll_djbec.py
diff --git a/mmgen/keccak.py b/mmgen/contrib/keccak.py
similarity index 100%
rename from mmgen/keccak.py
rename to mmgen/contrib/keccak.py
diff --git a/mmgen/license.py b/mmgen/contrib/license.py
similarity index 99%
rename from mmgen/license.py
rename to mmgen/contrib/license.py
index 1ba4f3e0..c2d9e6f6 100755
--- a/mmgen/license.py
+++ b/mmgen/contrib/license.py
@@ -20,7 +20,7 @@
 license.py:  Copyright notice and text of GPLv3
 """
 
-from .globalvars import g
+from ..globalvars import g
 
 warning = f"""
   {g.proj_name} Copyright (C) {g.Cdates} by {g.author} {g.email}.  This
diff --git a/mmgen/data/version b/mmgen/data/version
index f3303951..0dcc20bf 100644
--- a/mmgen/data/version
+++ b/mmgen/data/version
@@ -1 +1 @@
-13.1.dev017
+13.1.dev018
diff --git a/mmgen/keygen.py b/mmgen/keygen.py
index 0796acca..0275e2f8 100755
--- a/mmgen/keygen.py
+++ b/mmgen/keygen.py
@@ -137,7 +137,7 @@ class keygen_backend:
 
 			def __init__(self):
 				super().__init__()
-				from .ed25519 import edwards,encodepoint,B,scalarmult
+				from .contrib.ed25519 import edwards,encodepoint,B,scalarmult
 				self.edwards     = edwards
 				self.encodepoint = encodepoint
 				self.B           = B
@@ -173,7 +173,7 @@ class keygen_backend:
 
 			def __init__(self):
 				super().__init__()
-				from .ed25519ll_djbec import scalarmult
+				from .contrib.ed25519ll_djbec import scalarmult
 				self.scalarmult = scalarmult
 
 	class zcash_z:
diff --git a/mmgen/proto/btc.py b/mmgen/proto/btc.py
index 193651dc..3c85941c 100755
--- a/mmgen/proto/btc.py
+++ b/mmgen/proto/btc.py
@@ -86,7 +86,7 @@ class mainnet(CoinProtocol.Secp256k1): # chainparams.cpp
 	def parse_addr(self,addr):
 
 		if 'B' in self.mmtypes and addr[:len(self.bech32_hrp)] == self.bech32_hrp:
-			import mmgen.base_proto.bitcoin.bech32 as bech32
+			import mmgen.contrib.bech32 as bech32
 			ret = bech32.decode(self.bech32_hrp,addr)
 
 			if ret[0] != self.witness_vernum:
@@ -117,7 +117,7 @@ class mainnet(CoinProtocol.Secp256k1): # chainparams.cpp
 
 	def pubhash2bech32addr(self,pubhash):
 		d = list(pubhash)
-		import mmgen.base_proto.bitcoin.bech32 as bech32
+		import mmgen.contrib.bech32 as bech32
 		return bech32.bech32_encode(self.bech32_hrp,[self.witness_vernum]+bech32.convertbits(d,8,5))
 
 class testnet(mainnet):
diff --git a/mmgen/proto/xmr.py b/mmgen/proto/xmr.py
index 115e2538..2112c83f 100755
--- a/mmgen/proto/xmr.py
+++ b/mmgen/proto/xmr.py
@@ -34,7 +34,7 @@ class mainnet(CoinProtocol.DummyWIF,CoinProtocol.Base):
 	coin_amt       = 'XMRAmt'
 
 	def preprocess_key(self,sec,pubkey_type): # reduce key
-		from ..ed25519 import l
+		from ..contrib.ed25519 import l
 		return int.to_bytes(
 			int.from_bytes( sec[::-1], 'big' ) % l,
 			self.privkey_len,
diff --git a/mmgen/util.py b/mmgen/util.py
index 6e061c01..c07dbcda 100755
--- a/mmgen/util.py
+++ b/mmgen/util.py
@@ -211,14 +211,14 @@ def get_keccak():
 	from .opts import opt
 	# called in opts.init() via CoinProtocol, so must use getattr():
 	if getattr(opt,'use_internal_keccak_module',False):
-		from .keccak import keccak_256
+		from .contrib.keccak import keccak_256
 		qmsg('Using internal keccak module by user request')
 		return keccak_256
 
 	try:
 		from sha3 import keccak_256
 	except:
-		from .keccak import keccak_256
+		from .contrib.keccak import keccak_256
 
 	return keccak_256
 
@@ -619,7 +619,7 @@ def do_license_msg(immed=False):
 	if opt.quiet or g.no_license or opt.yes or not g.stdin_tty:
 		return
 
-	import mmgen.license as gpl
+	import mmgen.contrib.license as gpl
 	msg(gpl.warning)
 
 	from .term import get_char
diff --git a/setup.cfg b/setup.cfg
index 2213de70..02023bf0 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -41,6 +41,7 @@ install_requires =
 
 packages =
 	mmgen
+	mmgen.contrib
 	mmgen.base_proto
 	mmgen.base_proto.bitcoin
 	mmgen.base_proto.bitcoin.tx
diff --git a/test/hashfunc.py b/test/hashfunc.py
index dbc1e8ae..049062f5 100755
--- a/test/hashfunc.py
+++ b/test/hashfunc.py
@@ -84,7 +84,7 @@ class TestHashFunc(object):
 class TestKeccak(TestHashFunc):
 	desc = 'keccak_256'
 	def __init__(self):
-		from mmgen.keccak import keccak_256
+		from mmgen.contrib.keccak import keccak_256
 		import sha3
 		self.t_cls = keccak_256
 		self.hashlib = sha3
diff --git a/test/overlay/__init__.py b/test/overlay/__init__.py
index 9978353f..485a26e1 100644
--- a/test/overlay/__init__.py
+++ b/test/overlay/__init__.py
@@ -38,6 +38,7 @@ def overlay_setup(repo_root):
 		shutil.rmtree(overlay_dir,ignore_errors=True)
 		for d in (
 				'mmgen',
+				'mmgen.contrib',
 				'mmgen.base_proto',
 				'mmgen.base_proto.bitcoin',
 				'mmgen.base_proto.bitcoin.tx',