diff --git a/login_server/src/cpp/model/gradido/GroupMemberUpdate.cpp b/login_server/src/cpp/model/gradido/GroupMemberUpdate.cpp
index 145e1e97a..223baeb92 100644
--- a/login_server/src/cpp/model/gradido/GroupMemberUpdate.cpp
+++ b/login_server/src/cpp/model/gradido/GroupMemberUpdate.cpp
@@ -67,7 +67,7 @@ namespace model {
 			const static char functionName[] = { "GroupMemberUpdate::validate" };
 			if (mProtoMemberUpdate.user_pubkey().size() != KeyPairEd25519::getPublicKeySize()) {
 				addError(new Error(functionName, "pubkey not set or wrong size"));
-				return TRANSCATION_VALID_INVALID_PUBKEY;
+				return TRANSACTION_VALID_INVALID_PUBKEY;
 			}
 
 			if (mProtoMemberUpdate.member_update_type() != proto::gradido::GroupMemberUpdate::ADD_USER) {
diff --git a/login_server/src/cpp/model/gradido/Transaction.cpp b/login_server/src/cpp/model/gradido/Transaction.cpp
index c8708ce35..dd1655885 100644
--- a/login_server/src/cpp/model/gradido/Transaction.cpp
+++ b/login_server/src/cpp/model/gradido/Transaction.cpp
@@ -590,7 +590,7 @@ namespace model {
 			auto result = validate();
 			if (TRANSACTION_VALID_OK != result) {
 				if (   TRANSACTION_VALID_MISSING_SIGN == result || TRANSACTION_VALID_CODE_ERROR == result 
-					|| TRANSACTION_VALID_MISSING_PARAM == result || TRANSCATION_VALID_INVALID_PUBKEY == result
+					|| TRANSACTION_VALID_MISSING_PARAM == result || TRANSACTION_VALID_INVALID_PUBKEY == result
 					|| TRANSACTION_VALID_INVALID_SIGN == result) {
 					addError(new ParamError(function_name, "code error", TransactionValidationToString(result)));
 					//sendErrorsAsEmail();
diff --git a/login_server/src/cpp/model/gradido/TransactionBase.cpp b/login_server/src/cpp/model/gradido/TransactionBase.cpp
index 823a4c5ea..a8c983532 100644
--- a/login_server/src/cpp/model/gradido/TransactionBase.cpp
+++ b/login_server/src/cpp/model/gradido/TransactionBase.cpp
@@ -17,7 +17,7 @@ namespace model {
 			case TRANSACTION_VALID_INVALID_TARGET_DATE: return "invalid target date";
 			case TRANSACTION_VALID_CREATION_OUT_OF_BORDER: return "creation out of border";
 			case TRANSACTION_VALID_INVALID_AMOUNT: return "invalid amount";
-			case TRANSCATION_VALID_INVALID_PUBKEY: return "invalid pubkey";
+			case TRANSACTION_VALID_INVALID_PUBKEY: return "invalid pubkey";
 			case TRANSACTION_VALID_INVALID_GROUP_ALIAS: return "invalid group alias";
 			case TRANSACTION_VALID_INVALID_SIGN: return "invalid sign";
 			}
diff --git a/login_server/src/cpp/model/gradido/TransactionBase.h b/login_server/src/cpp/model/gradido/TransactionBase.h
index bea79c971..da8930443 100644
--- a/login_server/src/cpp/model/gradido/TransactionBase.h
+++ b/login_server/src/cpp/model/gradido/TransactionBase.h
@@ -29,7 +29,7 @@ namespace model {
 			TRANSACTION_VALID_INVALID_TARGET_DATE,
 			TRANSACTION_VALID_CREATION_OUT_OF_BORDER,
 			TRANSACTION_VALID_INVALID_AMOUNT,
-			TRANSCATION_VALID_INVALID_PUBKEY,
+			TRANSACTION_VALID_INVALID_PUBKEY,
 			TRANSACTION_VALID_INVALID_GROUP_ALIAS,
 			TRANSACTION_VALID_INVALID_SIGN
 		};
diff --git a/login_server/src/cpp/model/gradido/TransactionCreation.cpp b/login_server/src/cpp/model/gradido/TransactionCreation.cpp
index e53a5544b..7461b9bce 100644
--- a/login_server/src/cpp/model/gradido/TransactionCreation.cpp
+++ b/login_server/src/cpp/model/gradido/TransactionCreation.cpp
@@ -108,7 +108,7 @@ namespace model {
 
 			if (mProtoCreation.receiver().pubkey().size() != KeyPairEd25519::getPublicKeySize()) {
 				addError(new Error(function_name, "receiver pubkey has invalid size"));
-				return TRANSCATION_VALID_INVALID_PUBKEY;
+				return TRANSACTION_VALID_INVALID_PUBKEY;
 			}
 
 			// TODO: check creation amount from last 3 month from node server
diff --git a/login_server/src/cpp/model/gradido/TransactionTransfer.cpp b/login_server/src/cpp/model/gradido/TransactionTransfer.cpp
index 6e458a87a..759d79690 100644
--- a/login_server/src/cpp/model/gradido/TransactionTransfer.cpp
+++ b/login_server/src/cpp/model/gradido/TransactionTransfer.cpp
@@ -176,11 +176,15 @@ namespace model {
 			}
 			if (receiver_pubkey->size() != KeyPairEd25519::getPublicKeySize()) {
 				addError(new Error(function_name, "invalid size of receiver pubkey"));
-				return TRANSCATION_VALID_INVALID_PUBKEY;
+				return TRANSACTION_VALID_INVALID_PUBKEY;
 			}
 			if (sender->pubkey().size() != KeyPairEd25519::getPublicKeySize()) {
 				addError(new Error(function_name, "invalid size of sender pubkey"));
-				return TRANSCATION_VALID_INVALID_PUBKEY;
+				return TRANSACTION_VALID_INVALID_PUBKEY;
+			}
+			if(0 == memcmp(sender->pubkey().data(), receiver_pubkey->data(), KeyPairEd25519::getPublicKeySize())) {
+				addError(new Error(function_name, "sender and receiver are the same"));
+				return TRANSACTION_VALID_INVALID_PUBKEY;
 			}
 			return TRANSACTION_VALID_OK;
 		}