diff --git a/tools/keytool b/tools/keytool
index 8688940e1d..e0b59525ec 100755
--- a/tools/keytool
+++ b/tools/keytool
@@ -6,7 +6,7 @@ import pyblake2
 
 
 def hex(by):
-    return str(binascii.hexlify(by), 'ascii')
+    return binascii.hexlify(by).decode()
 
 
 def combine_keys(pks):
@@ -55,7 +55,7 @@ def compute_mask(combination, m, n):
 
 def createPubkey():
     print('Enter randomness: ', end='')
-    seckey = ed25519raw.H(input().encode('utf-8'))[0:32]
+    seckey = ed25519raw.H(input().encode())[0:32]
     pubkey = ed25519raw.publickey(seckey)
     print('Secret Key: %s' % hex(seckey))
     print('Public Key: %s' % hex(pubkey))
@@ -63,7 +63,7 @@ def createPubkey():
 
 def combinePubkeys(m, n):
     if binom(n, m) > 100:
-        raise Exception("Too many keys")
+        raise Exception('Too many keys')
     pks = []
     for i in range(0, n):
         print('Enter pubkey %d: ' % i, end='')
@@ -91,7 +91,7 @@ def get_nonce(sk, data, ctr):
     a = 2 ** (b - 2) + sum(2 ** i * ed25519raw.bit(h, i) for i in range(3, b - 2))
     r = ed25519raw.Hint(bytes([h[i] for i in range(b >> 3, b >> 2)]) + data + binascii.unhexlify('%08x' % ctr))
     R = ed25519raw.scalarmult(ed25519raw.B, r)
-    return (r, ed25519raw.encodepoint(R))
+    return r, ed25519raw.encodepoint(R)
 
 
 def phase1(data):
@@ -101,7 +101,7 @@ def phase1(data):
     ctr = int(input())
     print('Enter privkey: ', end='')
     seckey = binascii.unhexlify(input())
-    (_, R) = get_nonce(seckey, digest, ctr)
+    _, R = get_nonce(seckey, digest, ctr)
     print('Local commit: %s' % hex(R))
 
 
@@ -202,9 +202,9 @@ def main():
 
 
 def test():
-    data = sys.argv[1].encode('utf-8')
-    N = 5
-    keyset = [1, 3, 4]
+    data = sys.argv[1].encode()
+    N = 3
+    keyset = [0, 2]
 
     digest = pyblake2.blake2s(data).digest()
     print('Digest: %s' % hex(digest))
@@ -215,7 +215,7 @@ def test():
     sigs = []
     for i in range(0, N):
         print('----- Key %d ------' % (i + 1))
-        seckey = ed25519raw.H(("key%d" % (i + 1)).encode('utf-8'))[0:32]
+        seckey = bytes([0x41 + i]) * 32
         pubkey = ed25519raw.publickey(seckey)
         print('Secret Key: %s' % hex(seckey))
         print('Public Key: %s' % hex(pubkey))
@@ -235,7 +235,7 @@ def test():
     print('Global commit: %s' % hex(globalR))
     print('-----------------')
 
-    for i in range(0, 5):
+    for i in range(0, N):
         seckey = sks[i]
         pubkey = pks[i]
         r = nonces[i]
@@ -250,7 +250,7 @@ def test():
         sigs.append(ed25519raw.encodeint(S))
 
     print('-----------------')
-    sig = combine_sig(globalR, [sigs[i] for i in [1, 3, 4]])
+    sig = combine_sig(globalR, [sigs[i] for i in keyset])
     print('Global sig: %s' % hex(sig))
     ed25519raw.checkvalid(sig, digest, globalPk)
     print('Valid Signature!')