diff --git a/silkaj/crypto_tools.py b/silkaj/crypto_tools.py
index ae28606ed56dce45d404b94cab428a4d4423ab57..637d2c36a3f2192c631693d4144a3ec7b77d3e92 100644
--- a/silkaj/crypto_tools.py
+++ b/silkaj/crypto_tools.py
@@ -22,7 +22,7 @@ from silkaj.constants import PUBKEY_PATTERN
 
 PUBKEY_DELIMITED_PATTERN = "^{0}$".format(PUBKEY_PATTERN)
 CHECKSUM_PATTERN = "[1-9A-HJ-NP-Za-km-z]{3}"
-PUBKEY_CHECKSUM_PATTERN = "^{0}!{1}$".format(PUBKEY_PATTERN, CHECKSUM_PATTERN)
+PUBKEY_CHECKSUM_PATTERN = "^{0}:{1}$".format(PUBKEY_PATTERN, CHECKSUM_PATTERN)
 
 
 def check_public_key(pubkey, display_error):
@@ -34,7 +34,7 @@ def check_public_key(pubkey, display_error):
     if re.search(re.compile(PUBKEY_DELIMITED_PATTERN), pubkey):
         return pubkey
     elif re.search(re.compile(PUBKEY_CHECKSUM_PATTERN), pubkey):
-        pubkey, checksum = pubkey.split("!")
+        pubkey, checksum = pubkey.split(":")
         pubkey_byte = b58_decode(pubkey)
         checksum_calculed = b58_encode(
             hash.sha256(
@@ -44,7 +44,7 @@ def check_public_key(pubkey, display_error):
         if checksum_calculed == checksum:
             return pubkey
         else:
-            print("Error: bad checksum for following public key:")
+            print("Error: Wrong checksum for following public key:")
             return False
 
     elif display_error:
diff --git a/silkaj/tx.py b/silkaj/tx.py
index 5aa890927608a14fa8d977cad3e6779c36bd8f44..c0e6e74268c8908af7d4143845aeb79f29403049 100644
--- a/silkaj/tx.py
+++ b/silkaj/tx.py
@@ -76,7 +76,7 @@ from duniterpy.documents.transaction import OutputSource, Unlock, SIGParameter
     "-r",
     multiple=True,
     required=True,
-    help="Pubkey(s)’ recipients + optional checksum:\n-r <pubkey>[!checksum]\n\
+    help="Pubkey(s)’ recipients + optional checksum:\n-r <pubkey>[:checksum]\n\
 Sending to many recipients is possible:\n\
 * With one amount, all will receive the amount\n\
 * With many amounts (one per recipient)",
@@ -84,7 +84,7 @@ Sending to many recipients is possible:\n\
 @option("--comment", "-c", default="", help="Comment")
 @option(
     "--outputBackChange",
-    help="Pubkey recipient to send the rest of the transaction: <pubkey[!checksum]>",
+    help="Pubkey recipient to send the rest of the transaction: <pubkey[:checksum]>",
 )
 @option("--yes", "-y", is_flag=True, help="Assume yes. Do not prompt confirmation")
 @coroutine