Add a new transaction whose validity and gas payment can be defined abstractly. Instead of relying solely on a single ECDSA signature, accounts may freely define and interpret their signature scheme using any cryptographic system.
This new transaction provides a native off-ramp from the elliptic curve based cryptographic system used to authenticate transactions today, to post-quantum (PQ) secure systems.
In doing so, it realizes the original vision of account abstraction: unlinking accounts from a prescribed ECDSA key and support alternative fee payment schemes. The assumption of an account simply becomes an address with code. It leverages the EVM to support arbitrary user-defined definitions of validation and gas payment.
| Name | Value |
|---|---|
FRAME_TX_TYPE | 0x06 |
FRAME_TX_INTRINSIC_COST | 15000 |
ENTRY_POINT | address(0xaa) |
MAX_FRAMES | 10^3 |
| Name | Value |
|---|---|
APPROVE | 0xaa |
TXPARAMLOAD | 0xb0 |
TXPARAMSIZE | 0xb1 |
TXPARAMCOPY | 0xb2 |
A new EIP-2718 transaction with type FRAME_TX_TYPE is introduced. Transactions of this type are referred to as "Frame transactions".
The payload is defined as the RLP serialization of the following:
If no blobs are included, blob_versioned_hashes must be an empty list and max_fee_per_blob_gas must be 0.
There are three modes:
| Mode | Name | Summary |
|---|---|---|
| 0 | DEFAULT | Execute frame as ENTRY_POINT |
| 1 | VERIFY | Frame identifies as transaction validation |
| 2 | SENDER | Execute frame as sender |
DEFAULT ModeFrame executes as regular call where the caller address is ENTRY_POINT.
VERIFY ModeIdentifies the frame as a validation frame. Its purpose is to verify that a sender and/or payer authorized the transaction. It must call APPROVE during execution. Failure to do so will result in the whole transaction being invalid.
The execution behaves the same as STATICCALL, state cannot be modified.
Frames in this mode will have their data elided from signature hash calculation and from introspection by other frames.
SENDER ModeFrame executes as regular call where the caller address is sender. This mode effectively acts on behalf of the transaction sender and can only be used after explicitly approved.
Some validity constraints can be determined statically. They are outlined below:
The ReceiptPayload is defined as:
payer is the address of the account that paid the fees for the transaction. status is the return code of the top-level call.
With the frame transaction, the signature may be at an arbitrary location in the frame list. In the canonical signature hash any frame with mode VERIFY will have its data elided:
APPROVE opcode (0xaa)The APPROVE opcode is like RETURN (0xf3). It exits the current context successfully and updates the transaction-scoped approval context based on the scope operand. It can only be called when CALLER == frame.target, otherwise it results in an exceptional halt.
| Stack | Value |
|---|---|
top - 0 | offset |
top - 1 | length |
top - 2 | scope |
The scope operand must be one of the following values:
0x0: Approval of execution - the sender contract approves future frames calling on its behalf. Only valid when frame.target equals tx.sender.0x1: Approval of payment - the contract approves paying the total gas cost for the transaction.0x2: Approval of execution and payment - combines both 0x0 and 0x1.Any other value results in an exceptional halt.
The behavior of APPROVE is defined as follows:
APPROVE is called when CALLER != frame.target, revert.0,1, and 2, execute the following:
0x0: Set sender_approved = true.
sender_approved was already set, revert the frame.CALLER != tx.sender, revert the frame.0x1: Increment the sender's nonce, collect the total gas cost of the transaction from the account, and set payer_approved = true.
frame.target has insufficient balance, revert the frame.sender_approved == false, revert the frame.0x2: sender_approved = true, increment the sender's nonce, collect the total gas cost of the transaction from frame.target, and set payer_approved = true.
sender_approved or payer_approved was already set, revert the frame.CALLER != tx.sender, revert the frame.frame.target has insufficient balance, revert the frame.TXPARAM* opcodesThe TXPARAMLOAD (0xb0), TXPARAMSIZE (0xb1), and TXPARAMCOPY (0xb2) opcodes follow the pattern of CALLDATA* / RETURNDATA* opcode families. Gas cost follows standard EVM memory expansion costs.
Each TXPARAM* opcode takes two extra stack input values before the CALLDATA* equivalent inputs. The values of these inputs are as follows:
in1 | in2 | Return value | Size |
|---|---|---|---|
| 0x00 | must be 0 | current transaction type | 32 |
| 0x01 | must be 0 | nonce | 32 |
| 0x02 | must be 0 | sender | 32 |
| 0x03 | must be 0 | max_priority_fee_per_gas | 32 |
| 0x04 | must be 0 | max_fee_per_gas | 32 |
| 0x05 | must be 0 | max_fee_per_blob_gas | 32 |
| 0x06 | must be 0 | max cost (basefee=max, all gas used, includes blob cost and intrinsic cost) | 32 |
| 0x07 | must be 0 | len(blob_versioned_hashes) | 32 |
| 0x08 | must be 0 | compute_sig_hash(tx) | 32 |
| 0x09 | must be 0 | len(frames) | 32 |
| 0x10 | must be 0 | currently executing frame index | 32 |
| 0x11 | frame index | target | 32 |
| 0x12 | frame index | data | dynamic |
| 0x13 | frame index | gas_limit | 32 |
| 0x14 | frame index | mode | 32 |
| 0x15 | frame index | status (exceptional halt if current/future) | 32 |
Notes:
status field (0x15) returns 0 for failure or 1 for success.>= len(frames)) and blob index results in an exceptional halt.in1 values (not defined in the table above) result in an exceptional halt.data field (0x12) returns size 0 value when called on a frame with VERIFY set.When processing a frame transaction, perform the following steps.
Perform stateful validation check:
tx.nonce == state[tx.sender].nonceInitialize with transaction-scoped variables:
payer_approved = falsesender_approved = falseThen for each call frame:
mode, target, gas_limit, and data.
target is null, set the call target to tx.sender.SENDER:
sender_approved must be true. If not, the transaction is invalid.caller as tx.sender.DEFAULT or VERIFY:
caller to ENTRY_POINT.ORIGIN opcode returns frame caller throughout all call depths.VERIFY and the frame did not successfully call APPROVE, the transaction is invalid.After executing all frames, verify that payer_approved == true. If it is, refund any unpaid gas to the gas payer. If it is not, the whole transaction is invalid.
Note: it is implied by the handling that the sender must approve the transaction before the payer and that once sender_approved or payer_approved become true they cannot be re-approved or reverted.
A few cross-frame interactions to note:
TSTORE and TLOAD transient storage between frames.The total gas limit of the transaction is:
Where calldata_cost is calculated per standard EVM rules (4 gas per zero byte, 16 gas per non-zero byte).
The total fee is defined as:
The effective_gas_price is calculated per EIP-1559 and blob_fees is calculated as per EIP-4844.
Each frame has its own gas_limit allocation. Unused gas from a frame is not available to subsequent frames. After all frames execute, the gas refund is calculated as:
This refund is returned to the gas payer (the target that called APPROVE(0x1) or APPROVE(0x2)) and added back to the block gas pool. Note: This refund mechanism is separate from EIP-3529 storage refunds.
The canonical signature hash is provided in TXPARAMLOAD to simplify the development of smart accounts.
Computing the signature hash in EVM is complicated and expensive. While using the canonical signature hash is not mandatory, it is strongly recommended. Creating a bespoke signature requires precise commitment to the underlying transaction data. Without this, it's possible that some elements can be manipulated in-the-air while the transaction is pending and have unexpected effects. This is known as transaction malleability. Using the canonical signature hash avoids malleability of the frames other than VERIFY.
The frame.data of VERIFY frames is elided from the signature hash. This is done for two reasons:
VERIFY frame to approve the gas payment. Here, the input data to the sponsor is intentionally left malleable so it can be added onto the transaction after the sender has made its signature. Notably, the frame.target of VERIFY frames is covered by the signature hash, i.e. the sender chooses the sponsor address explicitly.APPROVE calling conventionOriginally APPROVE was meant to extend the space of return statuses from 0 and j 1 today to 0 to 4. However, this would mean smart accounts deployed today would not beable to modify their contract code to return with a different value at the top level. For this reason, we've chosen behavior above: APPROVE terminates the executing frame successfully like RETURN, but it actually updates the transaction scoped values sender_approved and payer_approved during execution. It is still required that only the sender can toggle the sender_approved to true. Only the frame.target can call APPROVE generally, because it can allow the transaction pool and other frames to better reason about VERIFY mode frames.
The payer cannot be determined statically from a frame transaction and is relevant to users. The only way to provide this information safely and efficiently over the JSON-RPC is to record this data in the receipt object.
The EIP-7702 authorization list heavily relies on ECDSA cryptography to determine the authority of accounts to delegate code. While delegations could be used in other manners later, it does not satisfy the PQ goals of the frame transaction.
The access list was introduced to address a particular backwards compatibility issue that was caused by EIP-2929. The risk-reward of using an access list successfully is high. A single miss, paying to warm a storage slot that does not end up getting used, causes the overall transaction cost to be greater than had it not been included at all.
Future optimizations based on pre-announcing state elements a transaction will touch will be covered by block level access lists.
It is not required because the account code can send value.
| Frame | Caller | Target | Data | Mode |
|---|---|---|---|---|
| 0 | ENTRY_POINT | Null (sender) | Signature | VERIFY |
| 1 | Sender | Target | Call data | SENDER |
Frame 0 verifies the signature and calls APPROVE(0x2) to approve both execution and payment. Frame 1 executes and exits normally via RETURN.
The mempool can process this transaction with the following static validation and call:
VERIFY frame.| Frame | Caller | Target | Data | Mode |
|---|---|---|---|---|
| 0 | ENTRY_POINT | Null (sender) | Signature | VERIFY |
| 1 | Sender | Null (sender) | Destination/Amount | SENDER |
A simple transfer is performed by instructing the account to send ETH to the destination account. This requires two frames for mempool compatibility, since the validation phase of the transaction has to be static.
This is listed here to illustrate why the transaction type has no built-in value field.
| Frame | Caller | Target | Data | Mode |
|---|---|---|---|---|
| 0 | ENTRY_POINT | Deployer | Initcode, Salt | DEFAULT |
| 1 | ENTRY_POINT | Null (sender) | Signature | VERIFY |
| 2 | Sender | Null (sender) | Destination/Amount | SENDER |
This example illustrates the initial deployment flow for a smart account at the sender address. Since the address needs to have code in order to validate the transaction, the transaction must deploy the code before verification.
The first frame would call a deployer contract, like EIP-7997. The deployer determines the address in a deterministic way, such as by hashing the initcode and salt. However, since the transaction sender is not authenticated at this point, the user must choose an initcode which is safe to deploy by anyone.
| Frame | Caller | Target | Data | Mode |
|---|---|---|---|---|
| 0 | ENTRY_POINT | Null (sender) | Signature | VERIFY |
| 1 | ENTRY_POINT | Sponsor | Sponsor data | VERIFY |
| 2 | Sender | ERC-20 | transfer(Sponsor,fees) | SENDER |
| 3 | Sender | Target addr | Call data | SENDER |
| 4 | ENTRY_POINT | Sponsor | Post op call | DEFAULT |
APPROVE(0x0) to authorize execution from sender.APPROVE(0x1) to authorize payment.Basic transaction sending ETH from a smart account:
| Field | Bytes |
|---|---|
| Tx wrapper | 1 |
| Chain ID | 1 |
| Nonce | 2 |
| Sender | 20 |
| Max priority fee | 5 |
| Max fee | 5 |
| Max fee per blob gas | 1 |
| Blob versioned hashes (empty) | 1 |
| Frames wrapper | 1 |
| Sender validation frame: target | 1 |
| Sender validation frame: gas | 2 |
| Sender validation frame: data | 65 |
| Sender validation frame: mode | 1 |
| Execution frame: target | 1 |
| Execution frame: gas | 1 |
| Execution frame: data | 20+5 |
| Execution frame: mode | 1 |
| Total | 134 |
Notes: Nonce assumes < 65536 prior sends. Fees assume < 1099 gwei. Validation frame target is 1 byte because target is tx.sender. Validation gas assumes <= 65,536 gas. Calldata is 65 bytes for ECDSA signature. Blob fields assume no blobs (empty list, zero max fee).
This is not much larger than an EIP-1559 transaction; the extra overhead is the need to specify the sender and amount in calldata explicitly.
First transaction from an account (add deployment frame):
| Field | Bytes |
|---|---|
| Deployment frame: target | 20 |
| Deployment frame: gas | 3 |
| Deployment frame: data | 100 |
| Deployment frame: mode | 1 |
| Total additional | 124 |
Notes: Gas assumes cost < 2^24. Calldata assumes small proxy.
Trustless pay-with-ERC-20 sponsor (add these frames):
| Field | Bytes |
|---|---|
| Sponsor validation frame: target | 20 |
| Sponsor validation frame: gas | 3 |
| Sponsor validation frame: calldata | 0 |
| Sponsor validation frame: mode | 1 |
| Send to sponsor frame: target | 20 |
| Send to sponsor frame: gas | 3 |
| Send to sponsor frame: calldata | 68 |
| Send to sponsor frame: mode | 1 |
| Sponsor post op frame: target | 20 |
| Sponsor post op frame: gas | 3 |
| Sponsor post op frame: calldata | 0 |
| Sponsor post op frame: mode | 1 |
| Total additional | 140 |
Notes: Sponsor can read info from other fields. ERC-20 transfer call is 68 bytes.
There is some inefficiency in the sponsor case, because the same sponsor address must appear in three places (sponsor validation, send to sponsor inside ERC-20 calldata, post op frame), and the ABI is inefficient (~12 + 24 bytes wasted on zeroes). This is difficult to mitigate in a "clean" way, because one of the duplicates is inside the ERC-20 call, "opaque" to the protocol. However, it is much less inefficient than ERC-4337, because not all of the data takes the hit of the 32-byte-per-field ABI overhead.
The ORIGIN opcode behavior changes for frame transactions, returning the frame's caller rather than the traditional transaction origin. This is consistent with the precedent set by EIP-7702, which already modified ORIGIN semantics. Contracts that rely on ORIGIN = CALLER for security checks (a discouraged pattern) may behave differently under frame transactions.
Frame transactions introduce new denial-of-service vectors for transaction pools that node operators must mitigate. Because validation logic is arbitrary EVM code, attackers can craft transactions that appear valid during initial validation but become invalid later. Without any additional policies, an attacker could submit many transactions whose validity depends on some shared state, then submit one transaction that modifies that state, and cause all other transactions to become invalid simultaneously. This wastes the computational resources nodes spent validating and storing these transactions.
A simple example is transactions that check block.timestamp:
Such transactions are valid when submitted but become invalid once the deadline passes, without any on-chain action required from the attacker.
Node implementations should consider restricting which opcodes and storage slots validation frames can access, similar to ERC-7562. This isolates transactions from each other and limits mass invalidation vectors.
It's recommended that to validate the transaction, a specific frame structure is enforced and the amount of gas that is expended executing the validation phase must be limited. Once the frame calls APPROVE(0x2), it can be included in the mempool and propagated to peers safely.
For deployment of the sender account in the first frame, the mempool must only allow specific and known deployer factory contracts to be used as frame.target, to ensure deployment is deterministic and independent of chain state.
In general, it can be assumed that handling of frame transactions imposes similar restrictions as EIP-7702 on mempool relay, i.e. only a single transaction can be pending for an account that uses frame transactions.
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