diff --git a/src/github.com/stellar/gateway/bridge/handlers/request_handler_authorize_test.go b/src/github.com/stellar/gateway/bridge/handlers/request_handler_authorize_test.go
index 521fbd4..cc4f4da 100644
--- a/src/github.com/stellar/gateway/bridge/handlers/request_handler_authorize_test.go
+++ b/src/github.com/stellar/gateway/bridge/handlers/request_handler_authorize_test.go
@@ -54,7 +54,7 @@ func TestRequestHandlerAuthorize(t *testing.T) {
 				    "name": "account_id"
 				  }
 				}`)
-				assert.Equal(t, expected, test.StringToJSONMap(responseString))
+				assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 			})
 		})
 
@@ -73,7 +73,7 @@ func TestRequestHandlerAuthorize(t *testing.T) {
 				    "name": "asset_code"
 				  }
 				}`)
-				assert.Equal(t, expected, test.StringToJSONMap(responseString))
+				assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 			})
 		})
 
diff --git a/src/github.com/stellar/gateway/bridge/handlers/request_handler_builder.go b/src/github.com/stellar/gateway/bridge/handlers/request_handler_builder.go
index 3fe0836..146334e 100644
--- a/src/github.com/stellar/gateway/bridge/handlers/request_handler_builder.go
+++ b/src/github.com/stellar/gateway/bridge/handlers/request_handler_builder.go
@@ -42,7 +42,7 @@ func (rh *RequestHandler) Builder(w http.ResponseWriter, r *http.Request) {
 
 	sequenceNumber, err := strconv.ParseUint(request.SequenceNumber, 10, 64)
 	if err != nil {
-		errorResponse := protocols.NewInvalidParameterError("sequence_number", request.SequenceNumber)
+		errorResponse := protocols.NewInvalidParameterError("sequence_number", request.SequenceNumber, "Sequence number must be a number")
 		log.WithFields(errorResponse.LogData).Error(errorResponse.Error())
 		server.Write(w, errorResponse)
 		return
diff --git a/src/github.com/stellar/gateway/bridge/handlers/request_handler_payment.go b/src/github.com/stellar/gateway/bridge/handlers/request_handler_payment.go
index 62cde96..447962f 100644
--- a/src/github.com/stellar/gateway/bridge/handlers/request_handler_payment.go
+++ b/src/github.com/stellar/gateway/bridge/handlers/request_handler_payment.go
@@ -134,10 +134,9 @@ func (rh *RequestHandler) Payment(w http.ResponseWriter, r *http.Request) {
 			}
 		}
 
-		_, err = keypair.Parse(destinationObject.AccountID)
-		if err != nil {
+		if !protocols.IsValidAccountID(destinationObject.AccountID) {
 			log.WithFields(log.Fields{"AccountId": destinationObject.AccountID}).Print("Invalid AccountId in destination")
-			server.Write(w, protocols.NewInvalidParameterError("destination", request.Destination))
+			server.Write(w, protocols.NewInvalidParameterError("destination", request.Destination, "Destination public key must start with `G`."))
 			return
 		}
 
@@ -231,7 +230,7 @@ func (rh *RequestHandler) Payment(w http.ResponseWriter, r *http.Request) {
 			id, err := strconv.ParseUint(memo, 10, 64)
 			if err != nil {
 				log.WithFields(log.Fields{"memo": memo}).Print("Cannot convert memo_id value to uint64")
-				server.Write(w, protocols.NewInvalidParameterError("memo", request.Memo))
+				server.Write(w, protocols.NewInvalidParameterError("memo", request.Memo, "Memo.id must be a number"))
 				return
 			}
 			memoMutator = b.MemoID{id}
@@ -241,7 +240,7 @@ func (rh *RequestHandler) Payment(w http.ResponseWriter, r *http.Request) {
 			memoBytes, err := hex.DecodeString(memo)
 			if err != nil || len(memoBytes) != 32 {
 				log.WithFields(log.Fields{"memo": memo}).Print("Cannot decode hash memo value")
-				server.Write(w, protocols.NewInvalidParameterError("memo", request.Memo))
+				server.Write(w, protocols.NewInvalidParameterError("memo", request.Memo, "Memo.hash must be 32 bytes and hex encoded."))
 				return
 			}
 			var b32 [32]byte
@@ -250,7 +249,7 @@ func (rh *RequestHandler) Payment(w http.ResponseWriter, r *http.Request) {
 			memoMutator = &b.MemoHash{hash}
 		default:
 			log.Print("Not supported memo type: ", memoType)
-			server.Write(w, protocols.NewInvalidParameterError("memo", request.Memo))
+			server.Write(w, protocols.NewInvalidParameterError("memo", request.Memo, "Memo type not supported"))
 			return
 		}
 
@@ -289,12 +288,12 @@ func (rh *RequestHandler) Payment(w http.ResponseWriter, r *http.Request) {
 			case tx.Err.Error() == "Asset code length is invalid":
 				server.Write(
 					w,
-					protocols.NewInvalidParameterError("asset_code", request.AssetCode),
+					protocols.NewInvalidParameterError("asset_code", request.AssetCode, "Asset code length is invalid"),
 				)
 			case strings.Contains(tx.Err.Error(), "cannot parse amount"):
 				server.Write(
 					w,
-					protocols.NewInvalidParameterError("amount", request.Amount),
+					protocols.NewInvalidParameterError("amount", request.Amount, "Cannot parse amount"),
 				)
 			default:
 				log.WithFields(log.Fields{"err": tx.Err}).Print("Transaction builder error")
diff --git a/src/github.com/stellar/gateway/bridge/handlers/request_handler_payment_test.go b/src/github.com/stellar/gateway/bridge/handlers/request_handler_payment_test.go
index f04453a..e5815b8 100644
--- a/src/github.com/stellar/gateway/bridge/handlers/request_handler_payment_test.go
+++ b/src/github.com/stellar/gateway/bridge/handlers/request_handler_payment_test.go
@@ -81,7 +81,7 @@ func TestRequestHandlerPayment(t *testing.T) {
     "name": "source"
   }
 }`)
-				assert.Equal(t, expected, test.StringToJSONMap(responseString))
+				assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 			})
 		})
 
@@ -111,7 +111,7 @@ func TestRequestHandlerPayment(t *testing.T) {
     "name": "destination"
   }
 }`)
-				assert.Equal(t, expected, test.StringToJSONMap(responseString))
+				assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 			})
 		})
 
@@ -345,7 +345,7 @@ func TestRequestHandlerPayment(t *testing.T) {
     "name": "asset_issuer"
   }
 }`)
-				assert.Equal(t, expected, test.StringToJSONMap(responseString))
+				assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 			})
 		})
 
@@ -395,7 +395,7 @@ func TestRequestHandlerPayment(t *testing.T) {
     "name": "asset_code"
   }
 }`)
-				assert.Equal(t, expected, test.StringToJSONMap(responseString))
+				assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 			})
 		})
 
@@ -445,7 +445,7 @@ func TestRequestHandlerPayment(t *testing.T) {
     "name": "amount"
   }
 }`)
-				assert.Equal(t, expected, test.StringToJSONMap(responseString))
+				assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 			})
 		})
 
@@ -565,7 +565,7 @@ func TestRequestHandlerPayment(t *testing.T) {
     "name": "memo"
   }
 }`)
-					assert.Equal(t, expected, test.StringToJSONMap(responseString))
+					assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 				})
 
 				Convey("unsupported memo_type", func() {
@@ -581,7 +581,7 @@ func TestRequestHandlerPayment(t *testing.T) {
     "name": "memo"
   }
 }`)
-					assert.Equal(t, expected, test.StringToJSONMap(responseString))
+					assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 				})
 
 				Convey("memo is attached to the transaction", func() {
diff --git a/src/github.com/stellar/gateway/compliance/handlers/request_handler_auth.go b/src/github.com/stellar/gateway/compliance/handlers/request_handler_auth.go
index 9777434..1d24fa5 100644
--- a/src/github.com/stellar/gateway/compliance/handlers/request_handler_auth.go
+++ b/src/github.com/stellar/gateway/compliance/handlers/request_handler_auth.go
@@ -55,9 +55,9 @@ func (rh *RequestHandler) HandlerAuth(c web.C, w http.ResponseWriter, r *http.Re
 		return
 	}
 
-	if senderStellarToml.SigningKey == "" {
-		errorResponse := protocols.NewInvalidParameterError("data.sender", authData.Sender)
-		log.WithFields(errorResponse.LogData).Warn("No SIGNING_KEY in stellar.toml of sender")
+	if !protocols.IsValidAccountID(senderStellarToml.SigningKey) {
+		errorResponse := protocols.NewInvalidParameterError("data.sender", authData.Sender, "SIGNING_KEY in stellar.toml of sender is invalid")
+		log.WithFields(errorResponse.LogData).Warn("SIGNING_KEY in stellar.toml of sender is invalid")
 		server.Write(w, errorResponse)
 		return
 	}
@@ -65,7 +65,7 @@ func (rh *RequestHandler) HandlerAuth(c web.C, w http.ResponseWriter, r *http.Re
 	// Verify signature
 	signatureBytes, err := base64.StdEncoding.DecodeString(authreq.Signature)
 	if err != nil {
-		errorResponse := protocols.NewInvalidParameterError("sig", authreq.Signature)
+		errorResponse := protocols.NewInvalidParameterError("sig", authreq.Signature, "Invalid base64 string.")
 		log.WithFields(errorResponse.LogData).Warn("Error decoding signature")
 		server.Write(w, errorResponse)
 		return
@@ -77,7 +77,7 @@ func (rh *RequestHandler) HandlerAuth(c web.C, w http.ResponseWriter, r *http.Re
 			"data":        authreq.Data,
 			"sig":         authreq.Signature,
 		}).Warn("Invalid signature")
-		errorResponse := protocols.NewInvalidParameterError("sig", authreq.Signature)
+		errorResponse := protocols.NewInvalidParameterError("sig", authreq.Signature, "Invalid signature.")
 		server.Write(w, errorResponse)
 		return
 	}
@@ -86,7 +86,7 @@ func (rh *RequestHandler) HandlerAuth(c web.C, w http.ResponseWriter, r *http.Re
 	var tx xdr.Transaction
 	_, err = xdr.Unmarshal(b64r, &tx)
 	if err != nil {
-		errorResponse := protocols.NewInvalidParameterError("data.tx", authData.Tx)
+		errorResponse := protocols.NewInvalidParameterError("data.tx", authData.Tx, "Error decoding Transaction XDR")
 		log.WithFields(log.Fields{
 			"err": err,
 			"tx":  authData.Tx,
@@ -96,7 +96,7 @@ func (rh *RequestHandler) HandlerAuth(c web.C, w http.ResponseWriter, r *http.Re
 	}
 
 	if tx.Memo.Hash == nil {
-		errorResponse := protocols.NewInvalidParameterError("data.tx", authData.Tx)
+		errorResponse := protocols.NewInvalidParameterError("data.tx", authData.Tx, "Transaction does not contain Memo.Hash")
 		log.WithFields(log.Fields{"tx": authData.Tx}).Warn("Transaction does not contain Memo.Hash")
 		server.Write(w, errorResponse)
 		return
@@ -107,7 +107,7 @@ func (rh *RequestHandler) HandlerAuth(c web.C, w http.ResponseWriter, r *http.Re
 	memoBytes := [32]byte(*tx.Memo.Hash)
 
 	if memoPreimageHashBytes != memoBytes {
-		errorResponse := protocols.NewInvalidParameterError("data.tx", authData.Tx)
+		errorResponse := protocols.NewInvalidParameterError("data.tx", authData.Tx, "Memo preimage hash does not equal tx Memo.Hash")
 
 		h := xdr.Hash(memoPreimageHashBytes)
 		tx.Memo.Hash = &h
diff --git a/src/github.com/stellar/gateway/compliance/handlers/request_handler_auth_test.go b/src/github.com/stellar/gateway/compliance/handlers/request_handler_auth_test.go
index 15e4e60..4eb2a91 100644
--- a/src/github.com/stellar/gateway/compliance/handlers/request_handler_auth_test.go
+++ b/src/github.com/stellar/gateway/compliance/handlers/request_handler_auth_test.go
@@ -84,7 +84,7 @@ func TestRequestHandlerAuth(t *testing.T) {
 					  "code": "invalid_parameter",
 					  "message": "Invalid parameter."
 					}`)
-			assert.Equal(t, expected, test.StringToJSONMap(responseString))
+			assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 		})
 
 		Convey("When data is invalid", func() {
@@ -100,7 +100,7 @@ func TestRequestHandlerAuth(t *testing.T) {
 					  "code": "invalid_parameter",
 					  "message": "Invalid parameter."
 					}`)
-			assert.Equal(t, expected, test.StringToJSONMap(responseString))
+			assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 		})
 
 		Convey("When sender's stellar.toml does not contain signing key", func() {
@@ -150,7 +150,7 @@ func TestRequestHandlerAuth(t *testing.T) {
 		    "name": "data.sender"
 		  }
 		}`)
-			assert.Equal(t, expected, test.StringToJSONMap(responseString))
+			assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 		})
 
 		Convey("When signature is invalid", func() {
@@ -213,7 +213,7 @@ func TestRequestHandlerAuth(t *testing.T) {
     "name": "sig"
   }
 }`)
-			assert.Equal(t, expected, test.StringToJSONMap(responseString))
+			assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 		})
 
 		Convey("When all params are valid", func() {
diff --git a/src/github.com/stellar/gateway/compliance/handlers/request_handler_send_test.go b/src/github.com/stellar/gateway/compliance/handlers/request_handler_send_test.go
index d4ff196..a82d3cc 100644
--- a/src/github.com/stellar/gateway/compliance/handlers/request_handler_send_test.go
+++ b/src/github.com/stellar/gateway/compliance/handlers/request_handler_send_test.go
@@ -108,7 +108,7 @@ func TestRequestHandlerSend(t *testing.T) {
 			    "name": "source"
 			  }
 			}`)
-			assert.Equal(t, expected, test.StringToJSONMap(responseString))
+			assert.Equal(t, expected, test.StringToJSONMap(responseString, "more_info"))
 		})
 
 		Convey("When params are valid", func() {
diff --git a/src/github.com/stellar/gateway/protocols/bridge/authorize.go b/src/github.com/stellar/gateway/protocols/bridge/authorize.go
index cdc7783..403fc92 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/authorize.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/authorize.go
@@ -6,7 +6,6 @@ import (
 
 	"github.com/stellar/gateway/bridge/config"
 	"github.com/stellar/gateway/protocols"
-	"github.com/stellar/go/keypair"
 )
 
 var (
@@ -45,9 +44,8 @@ func (request *AuthorizeRequest) Validate(allowedAssets []config.Asset, issuingA
 		return err
 	}
 
-	_, err = keypair.Parse(request.AccountID)
-	if err != nil {
-		return protocols.NewInvalidParameterError("account_id", request.AccountID)
+	if !protocols.IsValidAccountID(request.AccountID) {
+		return protocols.NewInvalidParameterError("account_id", request.AccountID, "Account ID must start with `G`.")
 	}
 
 	// Is asset allowed?
@@ -60,7 +58,7 @@ func (request *AuthorizeRequest) Validate(allowedAssets []config.Asset, issuingA
 	}
 
 	if !allowed {
-		return protocols.NewInvalidParameterError("asset_code", request.AssetCode)
+		return protocols.NewInvalidParameterError("asset_code", request.AssetCode, "Asset code not allowed.")
 	}
 
 	return nil
diff --git a/src/github.com/stellar/gateway/protocols/bridge/builder.go b/src/github.com/stellar/gateway/protocols/bridge/builder.go
index ab076ad..7e8c805 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/builder.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/builder.go
@@ -97,11 +97,11 @@ func (r BuilderRequest) Process() error {
 			err = json.Unmarshal(operation.RawBody, &manageData)
 			operationBody = manageData
 		default:
-			return protocols.NewInvalidParameterError("operations["+strconv.Itoa(i)+"][type]", string(operation.Type))
+			return protocols.NewInvalidParameterError("operations["+strconv.Itoa(i)+"][type]", string(operation.Type), "Invalid operation type.")
 		}
 
 		if err != nil {
-			return protocols.NewInvalidParameterError("operations["+strconv.Itoa(i)+"][body]", "", map[string]interface{}{"err": err})
+			return protocols.NewInvalidParameterError("operations["+strconv.Itoa(i)+"][body]", "", "Operation is invalid.", map[string]interface{}{"err": err})
 		}
 
 		r.Operations[i].Body = operationBody
@@ -113,12 +113,12 @@ func (r BuilderRequest) Process() error {
 // Validate validates if the request is correct.
 func (r BuilderRequest) Validate() error {
 	if !protocols.IsValidAccountID(r.Source) {
-		return protocols.NewInvalidParameterError("source", r.Source)
+		return protocols.NewInvalidParameterError("source", r.Source, "Source parameter must start with `G`.")
 	}
 
 	for i, signer := range r.Signers {
-		if !protocols.IsValidAccountID(signer) {
-			return protocols.NewInvalidParameterError("signers["+strconv.Itoa(i)+"]", signer)
+		if !protocols.IsValidSecret(signer) {
+			return protocols.NewInvalidParameterError("signers["+strconv.Itoa(i)+"]", signer, "Signer must start with `S`.")
 		}
 	}
 
diff --git a/src/github.com/stellar/gateway/protocols/bridge/builder_account_merge.go b/src/github.com/stellar/gateway/protocols/bridge/builder_account_merge.go
index 5132c11..1339107 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/builder_account_merge.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/builder_account_merge.go
@@ -25,11 +25,11 @@ func (op AccountMergeOperationBody) ToTransactionMutator() b.TransactionMutator
 // Validate validates if operation body is valid.
 func (op AccountMergeOperationBody) Validate() error {
 	if !protocols.IsValidAccountID(op.Destination) {
-		return protocols.NewInvalidParameterError("destination", op.Destination)
+		return protocols.NewInvalidParameterError("destination", op.Destination, "Destination must start with `G`.")
 	}
 
 	if op.Source != nil && !protocols.IsValidAccountID(*op.Source) {
-		return protocols.NewInvalidParameterError("source", *op.Source)
+		return protocols.NewInvalidParameterError("source", *op.Source, "Source must start with `G`.")
 	}
 
 	return nil
diff --git a/src/github.com/stellar/gateway/protocols/bridge/builder_allow_trust.go b/src/github.com/stellar/gateway/protocols/bridge/builder_allow_trust.go
index e9f8511..16e291a 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/builder_allow_trust.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/builder_allow_trust.go
@@ -31,15 +31,15 @@ func (op AllowTrustOperationBody) ToTransactionMutator() b.TransactionMutator {
 // Validate validates if operation body is valid.
 func (op AllowTrustOperationBody) Validate() error {
 	if !protocols.IsValidAssetCode(op.AssetCode) {
-		return protocols.NewInvalidParameterError("asset_code", op.AssetCode)
+		return protocols.NewInvalidParameterError("asset_code", op.AssetCode, "Asset code is invalid")
 	}
 
 	if !protocols.IsValidAccountID(op.Trustor) {
-		return protocols.NewInvalidParameterError("trustor", op.Trustor)
+		return protocols.NewInvalidParameterError("trustor", op.Trustor, "Trustor must be a public key (starting with `G`).")
 	}
 
 	if op.Source != nil && !protocols.IsValidAccountID(*op.Source) {
-		return protocols.NewInvalidParameterError("source", *op.Source)
+		return protocols.NewInvalidParameterError("source", *op.Source, "Source must be a public key (starting with `G`).")
 	}
 
 	return nil
diff --git a/src/github.com/stellar/gateway/protocols/bridge/builder_change_trust.go b/src/github.com/stellar/gateway/protocols/bridge/builder_change_trust.go
index 7f88b2b..f23a64a 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/builder_change_trust.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/builder_change_trust.go
@@ -36,17 +36,17 @@ func (op ChangeTrustOperationBody) ToTransactionMutator() b.TransactionMutator {
 // Validate validates if operation body is valid.
 func (op ChangeTrustOperationBody) Validate() error {
 	if !op.Asset.Validate() {
-		return protocols.NewInvalidParameterError("asset", op.Asset.String())
+		return protocols.NewInvalidParameterError("asset", op.Asset.String(), "Asset is invalid.")
 	}
 
 	if op.Limit != nil {
 		if !protocols.IsValidAmount(*op.Limit) {
-			return protocols.NewInvalidParameterError("limit", *op.Limit)
+			return protocols.NewInvalidParameterError("limit", *op.Limit, "Limit is not a valid amount.")
 		}
 	}
 
 	if op.Source != nil && !protocols.IsValidAccountID(*op.Source) {
-		return protocols.NewInvalidParameterError("source", *op.Source)
+		return protocols.NewInvalidParameterError("source", *op.Source, "Source must be a public key (starting with `G`).")
 	}
 
 	return nil
diff --git a/src/github.com/stellar/gateway/protocols/bridge/builder_create_account.go b/src/github.com/stellar/gateway/protocols/bridge/builder_create_account.go
index 49c71ef..99b0fd1 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/builder_create_account.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/builder_create_account.go
@@ -29,15 +29,15 @@ func (op CreateAccountOperationBody) ToTransactionMutator() b.TransactionMutator
 // Validate validates if operation body is valid.
 func (op CreateAccountOperationBody) Validate() error {
 	if !protocols.IsValidAccountID(op.Destination) {
-		return protocols.NewInvalidParameterError("destination", op.Destination)
+		return protocols.NewInvalidParameterError("destination", op.Destination, "Destination must be a public key (starting with `G`)")
 	}
 
 	if !protocols.IsValidAmount(op.StartingBalance) {
-		return protocols.NewInvalidParameterError("starting_balance", op.StartingBalance)
+		return protocols.NewInvalidParameterError("starting_balance", op.StartingBalance, "Not a valid amount.")
 	}
 
 	if op.Source != nil && !protocols.IsValidAccountID(*op.Source) {
-		return protocols.NewInvalidParameterError("source", *op.Source)
+		return protocols.NewInvalidParameterError("source", *op.Source, "Source must be a public key (starting with `G`)")
 	}
 
 	return nil
diff --git a/src/github.com/stellar/gateway/protocols/bridge/builder_inflation.go b/src/github.com/stellar/gateway/protocols/bridge/builder_inflation.go
index 40f11d8..74c92de 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/builder_inflation.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/builder_inflation.go
@@ -24,7 +24,7 @@ func (op InflationOperationBody) ToTransactionMutator() b.TransactionMutator {
 // Validate validates if operation body is valid.
 func (op InflationOperationBody) Validate() error {
 	if op.Source != nil && !protocols.IsValidAccountID(*op.Source) {
-		return protocols.NewInvalidParameterError("source", *op.Source)
+		return protocols.NewInvalidParameterError("source", *op.Source, "Source must be a public key (starting with `G`).")
 	}
 
 	return nil
diff --git a/src/github.com/stellar/gateway/protocols/bridge/builder_manage_data.go b/src/github.com/stellar/gateway/protocols/bridge/builder_manage_data.go
index 3fcc8a0..e5bd9f7 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/builder_manage_data.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/builder_manage_data.go
@@ -36,16 +36,16 @@ func (op ManageDataOperationBody) ToTransactionMutator() b.TransactionMutator {
 // Validate validates if operation body is valid.
 func (op ManageDataOperationBody) Validate() error {
 	if len(op.Name) > 64 {
-		return protocols.NewInvalidParameterError("name", op.Name)
+		return protocols.NewInvalidParameterError("name", op.Name, "Name must be less than or equal 64 characters.")
 	}
 
 	data, err := base64.StdEncoding.DecodeString(op.Data)
 	if err != nil || len(data) > 64 {
-		return protocols.NewInvalidParameterError("data", op.Data)
+		return protocols.NewInvalidParameterError("data", op.Data, "Not a valid base64 string.")
 	}
 
 	if op.Source != nil && !protocols.IsValidAccountID(*op.Source) {
-		return protocols.NewInvalidParameterError("source", *op.Source)
+		return protocols.NewInvalidParameterError("source", *op.Source, "Source must be a public key (starting with `G`).")
 	}
 
 	return nil
diff --git a/src/github.com/stellar/gateway/protocols/bridge/builder_manage_offer.go b/src/github.com/stellar/gateway/protocols/bridge/builder_manage_offer.go
index 95f97ee..ff2b75c 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/builder_manage_offer.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/builder_manage_offer.go
@@ -49,12 +49,12 @@ func (op ManageOfferOperationBody) Validate() error {
 	if op.OfferID != nil {
 		_, err := strconv.ParseUint(*op.OfferID, 10, 64)
 		if err != nil {
-			return protocols.NewInvalidParameterError("offer_id", *op.OfferID)
+			return protocols.NewInvalidParameterError("offer_id", *op.OfferID, "Not a number.")
 		}
 	}
 
 	if op.Source != nil && !protocols.IsValidAccountID(*op.Source) {
-		return protocols.NewInvalidParameterError("source", *op.Source)
+		return protocols.NewInvalidParameterError("source", *op.Source, "Source must be a public key (starting with `G`).")
 	}
 
 	return nil
diff --git a/src/github.com/stellar/gateway/protocols/bridge/builder_path_payment.go b/src/github.com/stellar/gateway/protocols/bridge/builder_path_payment.go
index eddb622..2f35f8e 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/builder_path_payment.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/builder_path_payment.go
@@ -63,32 +63,32 @@ func (op PathPaymentOperationBody) ToTransactionMutator() b.TransactionMutator {
 // Validate validates if operation body is valid.
 func (op PathPaymentOperationBody) Validate() error {
 	if !protocols.IsValidAccountID(op.Destination) {
-		return protocols.NewInvalidParameterError("destination", op.Destination)
+		return protocols.NewInvalidParameterError("destination", op.Destination, "Destination must be a public key (starting with `G`).")
 	}
 
 	if !protocols.IsValidAmount(op.SendMax) {
-		return protocols.NewInvalidParameterError("send_max", op.SendMax)
+		return protocols.NewInvalidParameterError("send_max", op.SendMax, "Not a valid amount.")
 	}
 
 	if !protocols.IsValidAmount(op.DestinationAmount) {
-		return protocols.NewInvalidParameterError("destination_amount", op.DestinationAmount)
+		return protocols.NewInvalidParameterError("destination_amount", op.DestinationAmount, "Not a valid amount.")
 	}
 
 	if !op.SendAsset.Validate() {
-		return protocols.NewInvalidParameterError("send_asset", op.SendAsset.String())
+		return protocols.NewInvalidParameterError("send_asset", op.SendAsset.String(), "Invalid asset.")
 	}
 
 	if !op.DestinationAsset.Validate() {
-		return protocols.NewInvalidParameterError("destination_asset", op.DestinationAsset.String())
+		return protocols.NewInvalidParameterError("destination_asset", op.DestinationAsset.String(), "Invalid asset.")
 	}
 
 	if op.Source != nil && !protocols.IsValidAccountID(*op.Source) {
-		return protocols.NewInvalidParameterError("source", *op.Source)
+		return protocols.NewInvalidParameterError("source", *op.Source, "Source must be a public key (starting with `G`).")
 	}
 
 	for i, asset := range op.Path {
 		if !asset.Validate() {
-			return protocols.NewInvalidParameterError("path["+strconv.Itoa(i)+"]", asset.String())
+			return protocols.NewInvalidParameterError("path["+strconv.Itoa(i)+"]", asset.String(), "Invalid asset.")
 		}
 	}
 
diff --git a/src/github.com/stellar/gateway/protocols/bridge/builder_payment.go b/src/github.com/stellar/gateway/protocols/bridge/builder_payment.go
index 119b618..2cb2ad6 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/builder_payment.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/builder_payment.go
@@ -41,19 +41,19 @@ func (op PaymentOperationBody) ToTransactionMutator() b.TransactionMutator {
 // Validate validates if operation body is valid.
 func (op PaymentOperationBody) Validate() error {
 	if !protocols.IsValidAccountID(op.Destination) {
-		return protocols.NewInvalidParameterError("destination", op.Destination)
+		return protocols.NewInvalidParameterError("destination", op.Destination, "Destination must be a public key (starting with `G`).")
 	}
 
 	if !protocols.IsValidAmount(op.Amount) {
-		return protocols.NewInvalidParameterError("amount", op.Amount)
+		return protocols.NewInvalidParameterError("amount", op.Amount, "Invalid amount.")
 	}
 
 	if !op.Asset.Validate() {
-		return protocols.NewInvalidParameterError("asset", op.Asset.String())
+		return protocols.NewInvalidParameterError("asset", op.Asset.String(), "Invalid asset.")
 	}
 
 	if op.Source != nil && !protocols.IsValidAccountID(*op.Source) {
-		return protocols.NewInvalidParameterError("source", *op.Source)
+		return protocols.NewInvalidParameterError("source", *op.Source, "Source must be a public key (starting with `G`).")
 	}
 
 	return nil
diff --git a/src/github.com/stellar/gateway/protocols/bridge/builder_set_options.go b/src/github.com/stellar/gateway/protocols/bridge/builder_set_options.go
index afdba6d..5527245 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/builder_set_options.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/builder_set_options.go
@@ -78,17 +78,17 @@ func (op SetOptionsOperationBody) ToTransactionMutator() b.TransactionMutator {
 // Validate validates if operation body is valid.
 func (op SetOptionsOperationBody) Validate() error {
 	if op.InflationDest != nil && !protocols.IsValidAccountID(*op.InflationDest) {
-		return protocols.NewInvalidParameterError("inflation_dest", *op.InflationDest)
+		return protocols.NewInvalidParameterError("inflation_dest", *op.InflationDest, "Inflation destination must be a public key (starting with `G`).")
 	}
 
 	if op.Signer != nil {
 		if !protocols.IsValidAccountID(op.Signer.PublicKey) {
-			return protocols.NewInvalidParameterError("signer.public_key", op.Signer.PublicKey)
+			return protocols.NewInvalidParameterError("signer.public_key", op.Signer.PublicKey, "Public key must be starting with `G`.")
 		}
 	}
 
 	if op.Source != nil && !protocols.IsValidAccountID(*op.Source) {
-		return protocols.NewInvalidParameterError("source", *op.Source)
+		return protocols.NewInvalidParameterError("source", *op.Source, "Source must be a public key (starting with `G`).")
 	}
 
 	return nil
diff --git a/src/github.com/stellar/gateway/protocols/bridge/payment.go b/src/github.com/stellar/gateway/protocols/bridge/payment.go
index a87df73..604d15c 100644
--- a/src/github.com/stellar/gateway/protocols/bridge/payment.go
+++ b/src/github.com/stellar/gateway/protocols/bridge/payment.go
@@ -130,7 +130,7 @@ func (request *PaymentRequest) Validate() error {
 	if request.Source != "" {
 		_, err = keypair.Parse(request.Source)
 		if err != nil {
-			return protocols.NewInvalidParameterError("source", request.Source)
+			return protocols.NewInvalidParameterError("source", request.Source, "Source must be a public key (starting with `G`).")
 		}
 	}
 
@@ -153,9 +153,8 @@ func (request *PaymentRequest) Validate() error {
 	}
 
 	if request.AssetIssuer != "" {
-		_, err := keypair.Parse(request.AssetIssuer)
-		if err != nil {
-			return protocols.NewInvalidParameterError("asset_issuer", request.AssetIssuer)
+		if !protocols.IsValidAccountID(request.AssetIssuer) {
+			return protocols.NewInvalidParameterError("asset_issuer", request.AssetIssuer, "Asset issuer must be a public key (starting with `G`).")
 		}
 	}
 
@@ -169,9 +168,8 @@ func (request *PaymentRequest) Validate() error {
 	}
 
 	if request.SendAssetIssuer != "" {
-		_, err := keypair.Parse(request.SendAssetIssuer)
-		if err != nil {
-			return protocols.NewInvalidParameterError("send_asset_issuer", request.SendAssetIssuer)
+		if !protocols.IsValidAccountID(request.SendAssetIssuer) {
+			return protocols.NewInvalidParameterError("send_asset_issuer", request.SendAssetIssuer, "Send asset issuer must be a public key (starting with `G`).")
 		}
 	}
 
diff --git a/src/github.com/stellar/gateway/protocols/common.go b/src/github.com/stellar/gateway/protocols/common.go
index 83c2635..8e4af6c 100644
--- a/src/github.com/stellar/gateway/protocols/common.go
+++ b/src/github.com/stellar/gateway/protocols/common.go
@@ -28,7 +28,7 @@ func (a Asset) ToBaseAsset() build.Asset {
 
 // String returns string representation of this asset
 func (a Asset) String() string {
-	return fmt.Sprintf("%+v", a)
+	return fmt.Sprintf("Code: %s, Issuer: %s", a.Code, a.Issuer)
 }
 
 // Validate checks if asset params are correct.
diff --git a/src/github.com/stellar/gateway/protocols/compliance/send.go b/src/github.com/stellar/gateway/protocols/compliance/send.go
index 667df1b..5a98b70 100644
--- a/src/github.com/stellar/gateway/protocols/compliance/send.go
+++ b/src/github.com/stellar/gateway/protocols/compliance/send.go
@@ -56,22 +56,21 @@ func (request *SendRequest) Validate() error {
 		return err
 	}
 
-	_, err = keypair.Parse(request.Source)
-	if err != nil {
-		return protocols.NewInvalidParameterError("source", request.Source)
+	if !protocols.IsValidAccountID(request.Source) {
+		return protocols.NewInvalidParameterError("source", request.Source, "Source must be a public key (starting with `G`).")
 	}
 
 	if !validateStellarAddress(request.Sender) {
-		return protocols.NewInvalidParameterError("sender", request.Sender)
+		return protocols.NewInvalidParameterError("sender", request.Sender, "Not a valid stellar address.")
 	}
 
 	if !validateStellarAddress(request.Destination) {
-		return protocols.NewInvalidParameterError("destination", request.Destination)
+		return protocols.NewInvalidParameterError("destination", request.Destination, "Not a valid stellar address.")
 	}
 
 	_, err = keypair.Parse(request.AssetIssuer)
-	if err != nil {
-		return protocols.NewInvalidParameterError("asset_issuer", request.AssetIssuer)
+	if !protocols.IsValidAccountID(request.AssetIssuer) {
+		return protocols.NewInvalidParameterError("asset_issuer", request.AssetIssuer, "Asset issuer must be a public key (starting with `G`).")
 	}
 
 	return nil
diff --git a/src/github.com/stellar/gateway/protocols/errors.go b/src/github.com/stellar/gateway/protocols/errors.go
index 1854195..afba17c 100644
--- a/src/github.com/stellar/gateway/protocols/errors.go
+++ b/src/github.com/stellar/gateway/protocols/errors.go
@@ -26,7 +26,7 @@ func NewInternalServerError(logMessage string, logData map[string]interface{}) *
 }
 
 // NewInvalidParameterError creates and returns a new InvalidParameterError
-func NewInvalidParameterError(name, value string, additionalLogData ...map[string]interface{}) *ErrorResponse {
+func NewInvalidParameterError(name, value, moreInfo string, additionalLogData ...map[string]interface{}) *ErrorResponse {
 	logData := map[string]interface{}{"name": name, "value": value}
 	if len(additionalLogData) == 1 {
 		for k, v := range additionalLogData[0] {
@@ -35,11 +35,12 @@ func NewInvalidParameterError(name, value string, additionalLogData ...map[strin
 	}
 
 	return &ErrorResponse{
-		Status:  InvalidParameterError.Status,
-		Code:    InvalidParameterError.Code,
-		Message: InvalidParameterError.Message,
-		Data:    map[string]interface{}{"name": name},
-		LogData: logData,
+		Status:   InvalidParameterError.Status,
+		Code:     InvalidParameterError.Code,
+		Message:  InvalidParameterError.Message,
+		MoreInfo: moreInfo,
+		Data:     map[string]interface{}{"name": name},
+		LogData:  logData,
 	}
 }
 
@@ -63,6 +64,8 @@ type ErrorResponse struct {
 	Code string `json:"code"`
 	// Error message that will be returned to API consumer
 	Message string `json:"message"`
+	// Additional information returned to API consumer
+	MoreInfo string `json:"more_info,omitempty"`
 	// Error data that will be returned to API consumer
 	Data map[string]interface{} `json:"data,omitempty"`
 	// Error message that will be logged.
diff --git a/src/github.com/stellar/gateway/protocols/validation.go b/src/github.com/stellar/gateway/protocols/validation.go
index 301615e..70109dd 100644
--- a/src/github.com/stellar/gateway/protocols/validation.go
+++ b/src/github.com/stellar/gateway/protocols/validation.go
@@ -11,6 +11,25 @@ func IsValidAccountID(accountID string) bool {
 	if err != nil {
 		return false
 	}
+
+	if accountID[0] != 'G' {
+		return false
+	}
+
+	return true
+}
+
+// IsValidSecret returns true if secret is valid
+func IsValidSecret(secret string) bool {
+	_, err := keypair.Parse(secret)
+	if err != nil {
+		return false
+	}
+
+	if secret[0] != 'S' {
+		return false
+	}
+
 	return true
 }
 
diff --git a/src/github.com/stellar/gateway/test/helpers.go b/src/github.com/stellar/gateway/test/helpers.go
index c323c52..37a912f 100644
--- a/src/github.com/stellar/gateway/test/helpers.go
+++ b/src/github.com/stellar/gateway/test/helpers.go
@@ -5,7 +5,13 @@ import (
 )
 
 // StringToJSONMap transforms
-func StringToJSONMap(value string) (m map[string]interface{}) {
-	json.Unmarshal([]byte(value), &m)
+func StringToJSONMap(value string, ignoredFields ...string) (m map[string]interface{}) {
+	err := json.Unmarshal([]byte(value), &m)
+	if err != nil {
+		panic(err)
+	}
+	for _, ignoredField := range ignoredFields {
+		delete(m, ignoredField)
+	}
 	return
 }