MsgTransferTokens

Executes token transfers between addresses.

Proto Definition

message MsgTransferTokens {
  string creator = 1; // Address initiating the transfer
  string collectionId = 2; // Collection containing tokens to transfer
  repeated Transfer transfers = 3; // Transfer operations (must pass approvals)
}

message MsgTransferTokensResponse {}

message Transfer {
  // The address of the sender of the transfer.
  string from = 1;
  // The addresses of the recipients of the transfer.
  repeated string toAddresses = 2;
  // The balances to be transferred.
  repeated Balance balances = 3;
  // If defined, we will use the predeterminedBalances from the specified approval to calculate the balances at execution time.
  // We will override the balances field with the precalculated balances. Only applicable for approvals with predeterminedBalances set.
  ApprovalIdentifierDetails precalculateBalancesFromApproval = 4;
  // The Merkle proofs / solutions for all Merkle challenges required for the transfer.
  repeated MerkleProof merkleProofs = 5;
  // The ETH signature proofs / solutions for all ETH signature challenges required for the transfer.
  repeated ETHSignatureProof ethSignatureProofs = 6;
  // The memo for the transfer.
  string memo = 7;
  // The prioritized approvals for the transfer. By default, we scan linearly through the approvals and use the first match.
  // This field can be used to prioritize specific approvals and scan through them first.
  repeated ApprovalIdentifierDetails prioritizedApprovals = 8;
  // Whether to only check prioritized approvals for the transfer.
  // If true, we will only check the prioritized approvals and fail if none of them match (i.e. do not check any non-prioritized approvals).
  // If false, we will check the prioritized approvals first and then scan through the rest of the approvals.
  bool onlyCheckPrioritizedCollectionApprovals = 9;
  // Whether to only check prioritized approvals for the transfer.
  // If true, we will only check the prioritized approvals and fail if none of them match (i.e. do not check any non-prioritized approvals).
  // If false, we will check the prioritized approvals first and then scan through the rest of the approvals.
  bool onlyCheckPrioritizedIncomingApprovals = 10;
  // Whether to only check prioritized approvals for the transfer.
  // If true, we will only check the prioritized approvals and fail if none of them match (i.e. do not check any non-prioritized approvals).
  // If false, we will check the prioritized approvals first and then scan through the rest of the approvals.
  bool onlyCheckPrioritizedOutgoingApprovals = 11;
  // The options for precalculating the balances.
  PrecalculationOptions precalculationOptions = 12;
}

message PrecalculationOptions {
  // The timestamp to override with when calculating the balances.
  string overrideTimestamp = 1;
  // The IDs to override with when calculating the balances.
  repeated UintRange tokenIdsOverride = 2;
}

Auto-Scan vs Prioritized Approvals

The transfer approval system operates in two modes to balance efficiency and precision:

Auto-Scan Mode (Default)

By default, the system automatically scans through available approvals to find a match for the transfer. This mode:

• Works with: Approvals using Empty Approval Criteria (no side effects)

• Behavior: Automatically finds and uses the first matching approval

• Use case: Simple transfers without custom logic or side effects

• No versioning required: The system handles approval selection automatically

Prioritized Approvals (Required for Side Effects)

CRITICAL REQUIREMENT: Any transfer with side effects or custom approval criteria MUST always be prioritized with proper versioning set. No exceptions.

Race Condition Protection

The versioning control ensures that before submitting, the user knows the exact approval they are using:

"prioritizedApprovals": [
    {
        "approvalId": "abc123",
        "approvalLevel": "collection",
        "approverAddress": "",
        "version": "2" // Must specify exact version
    }
]

Example: Coin Transfer Approval

// MUST be prioritized - has coin transfer side effects
"prioritizedApprovals": [
    {
        "approvalId": "reward-approval",
        "approvalLevel": "collection",
        "approverAddress": "",
        "version": "1"
    }
],
"onlyCheckPrioritizedCollectionApprovals": true

Example: Auto-Scan Safe Transfer

// Can use auto-scan - no side effects
"prioritizedApprovals": [], // Empty - will auto-scan

// Only will succeed if it finds an approval has empty approval criteria with no custom logic

Control Flags

• onlyCheckPrioritizedCollectionApprovals: If true, only check prioritized approvals

• onlyCheckPrioritizedIncomingApprovals: If true, only check prioritized incoming approvals

• onlyCheckPrioritizedOutgoingApprovals: If true, only check prioritized outgoing approvals

Setting these to true is recommended when using prioritized approvals to ensure deterministic behavior.

Related Documentation

• Empty Approval Criteria - Template for auto-scan compatible approvals

• Approval Criteria - Understanding approval complexity

• Coin Transfers - Side effect examples

Transfer Validation Process

Each transfer undergoes a systematic validation process to ensure security and proper authorization:

Validation Steps

PRE. CALCULATE BALANCES (if needed)
  └── If precalculateBalancesFromApproval is specified, we will use the predeterminedBalances from the specified approval to pre-calculate the balances at execution time.

1. BALANCE CHECK
   └── Verify sender has sufficient balances for the transfer including ownership times
   └── FAIL if insufficient balances

2. COLLECTION APPROVAL CHECK
   └── Scan collection-level approvals (prioritized first, then auto-scan) to find a match for the entire transfer
   └── If match found:
       ├── Check approval criteria (merkle proofs, amounts, timing, etc.) and constraints
       ├── Check if it overrides sender approvals (overridesFromOutgoingApprovals)
       ├── Check if it overrides recipient approvals (overridesToIncomingApprovals)
       └── PROCEED with override flags set
   └── Else:
        └── Continue scanning
   └── If some attempted transfer balances have no valid collection approval: FAIL

3. SENDER APPROVAL CHECK (if not overridden)
   └── Check sender's outgoing approvals for this transfer
   └── Verify approval criteria and constraints
   └── FAIL if no valid outgoing approval found

4. RECIPIENT APPROVAL CHECK (if not overridden)
   └── Check each recipient's incoming approvals
   └── Verify approval criteria and constraints
   └── FAIL if any recipient lacks valid incoming approval

5. EXECUTE TRANSFER
   └── Update balances
   └── Execute any approved side effects
   └── Emit transfer events
   └── SUCCESS

Override Behavior

Collection approvals can override user-level approvals:

• overridesFromOutgoingApprovals: true - Forcefully skips sender approval check

• overridesToIncomingApprovals: true - Forcefully skips recipient approval checks

This allows collection managers to enable transfers that would otherwise be blocked by user settings.

Failure Points

Transfers fail at the first validation step that doesn't pass:

1. Insufficient Balances - Sender doesn't own the tokens

2. No Collection Approval - No valid collection-level approval found

3. Blocked by Sender - Sender's outgoing approvals reject the transfer

4. Blocked by Recipient - Recipient's incoming approvals reject the transfer

ETH Signature Proofs

ETH Signature Proofs are required when transfers use ETH Signature Challenges. Each proof contains:

• nonce: The unique identifier that was signed

• signature: The Ethereum signature of the message nonce + "-" + creatorAddress

Important: Each signature can only be used once per challenge tracker. The system tracks used signatures to prevent replay attacks.

Related Documentation

• Transferability - Approval system overview

• Collection Approvals - Collection-level controls

• User Approvals - User-level settings

• ETH Signature Challenges - Ethereum signature requirements

Collection ID Auto-Lookup

If you specify collectionId as "0", it will automatically lookup the latest collection ID created. This can be used if you are creating a collection and do not know the official collection ID yet but want to perform a multi-message transaction.

Usage Example

# CLI command
bitbadgeschaind tx badges transfer-tokens '[tx-json]' --from sender-key

JSON Example

{
    "creator": "bb1initiator123...",
    "collectionId": "1",
    "transfers": [
        {
            "from": "bb1sender123...",
            "toAddresses": ["bb1recipient123..."],
            // Balances to transfer (can be left blank if you are using precalculateBalancesFromApproval)
            "balances": [
                {
                    "amount": "10",
                    "ownershipTimes": [
                        { "start": "1", "end": "18446744073709551615" }
                    ],
                    "tokenIds": [{ "start": "1", "end": "5" }]
                }
            ],
            // Specific approval to calculate balances dynamically for (from the approvalCriteria.predeterminedBalances)
            "precalculateBalancesFromApproval": {
                "approvalId": "",
                "approvalLevel": "",
                "approverAddress": "",
                "version": "0"
            },
            // Additional options dependent on what is allowed (e.g. allow timestamp override, token ID override, etc.)
            "precalculationOptions": {
                "overrideTimestamp": "0",
                "tokenIdsOverride": []
            },
            // Supply all merkle proofs for any merkle challenges that need to be satisfied
            "merkleProofs": [],
            // Supply all ETH signature proofs for any ETH signature challenges that need to be satisfied
            "ethSignatureProofs": [
                {
                    "nonce": "unique-nonce-001",
                    "signature": "0x..."
                }
            ],
            // Memo for the transfer (can be left blank)
            "memo": "",

            // Any approval IDs that you want to prioritize for this transfer
            // Note: All approvals with side effects must be prioritized with proper versioning
            "prioritizedApprovals": [
                {
                    "approvalId": "abc123",
                    "approvalLevel": "collection",
                    "approverAddress": "", // blank for collection, otherwise the address of the approver
                    "version": "0"
                }
            ],

            // If specified, we will stop checking after the prioritized approvals list.
            // If false, we will check prioritized first, but then continue to check the rest of the approvals in auto-scan mode
            "onlyCheckPrioritizedCollectionApprovals": false,
            "onlyCheckPrioritizedIncomingApprovals": false,
            "onlyCheckPrioritizedOutgoingApprovals": false
        }
    ]
}