Skip to main content

​
Ecotone: Blob Retrieval

With the Ecotone upgrade the retrieval stage is extended to support an additional DA source: EIP-4844 blobs. After the Ecotone upgrade we modify the iteration over batcher transactions to treat transactions of transaction-type == 0x03 (BLOB_TX_TYPE) differently. If the batcher transaction is a blob transaction, then its calldata MUST be ignored should it be present. Instead:
  • For each blob hash in blob_versioned_hashes, retrieve the blob that matches it. A blob may be retrieved from any of a number different sources. Retrieval from a local beacon-node, through the /eth/v1/beacon/blob_sidecars/ endpoint, with indices filter to skip unrelated blobs, is recommended. For each retrieved blob:
    • The blob SHOULD (MUST, if the source is untrusted) be cryptographically verified against its versioned hash.
    • If the blob has a valid encoding, decode it into its continuous byte-string and pass that on to the next phase. Otherwise the blob is ignored.
Note that batcher transactions of type blob must be processed in the same loop as other batcher transactions to preserve the invariant that batches are always processed in the order they appear in the block. We ignore calldata in blob transactions so that it may be used in the future for batch metadata or other purposes.

​
Blob Encoding

Each blob in a EIP-4844 transaction really consists of FIELD_ELEMENTS_PER_BLOB = 4096 field elements. Each field element is a number in a prime field of BLS_MODULUS = 52435875175126190479447740508185965837690552500527637822603658699938581184513. This number does not represent a full uint256: math.log2(BLS_MODULUS) = 254.8570894... The L1 consensus-specs describe the encoding of this polynomial. The field elements are encoded as big-endian integers (KZG_ENDIANNESS = big). To save computational overhead, only 254 bits per field element are used for rollup data. For efficient data encoding, 254 bits (equivalent to 31.75 bytes) are utilized. 4 elements combine to effectively use 127 bytes. 127 bytes of application-layer rollup data is encoded at a time, into 4 adjacent field elements of the blob: 
# read(N): read the next N bytes from the application-layer rollup-data. The next read starts where the last stopped.
# write(V): append V (one or more bytes) to the raw blob.
bytes tailA = read(31)
byte x = read(1)
byte A = x & 0b0011_1111
write(A)
write(tailA)

bytes tailB = read(31)
byte y = read(1)
byte B = (y & 0b0000_1111) | (x & 0b1100_0000) >> 2)
write(B)
write(tailB)

bytes tailC = read(31)
byte z = read(1)
byte C = z & 0b0011_1111
write(C)
write(tailC)

bytes tailD = read(31)
byte D = ((z & 0b1100_0000) >> 2) | ((y & 0b1111_0000) >> 4)
write(D)
write(tailD)
Each written field element looks like this:
  • Starts with one of the prepared 6-bit left-padded byte values, to keep the field element within valid range.
  • Followed by 31 bytes of application-layer data, to fill the low 31 bytes of the field element.
The written output should look like this: 
<----- element 0 -----><----- element 1 -----><----- element 2 -----><----- element 3 ----->
| byte A |  tailA...  || byte B |  tailB...  || byte C |  tailC...  || byte D |  tailD...  |
The above is repeated 1024 times, to fill all 4096 elements, with a total of (4 * 31 + 3) * 1024 = 130048 bytes of data. When decoding a blob, the top-most two bits of each field-element must be 0, to make the encoding/decoding bijective. The first byte of rollup-data (second byte in first field element) is used as a version-byte. In version 0, the next 3 bytes of data are used to encode the length of the rollup-data, as big-endian uint24. Any trailing data, past the length delimiter, must be 0, to keep the encoding/decoding bijective. If the length is larger than 130048 - 4, the blob is invalid. If any of the encoding is invalid, the blob as a whole must be ignored.

​
Network upgrade automation transactions

The Ecotone hardfork activation block contains the following transactions, in this order:
  • L1 Attributes Transaction, using the pre-Ecotone setL1BlockValues
  • User deposits from L1
  • Network Upgrade Transactions
    • L1Block deployment
    • GasPriceOracle deployment
    • Update L1Block Proxy ERC-1967 Implementation Slot
    • Update GasPriceOracle Proxy ERC-1967 Implementation Slot
    • GasPriceOracle Enable Ecotone
    • Beacon block roots contract deployment (EIP-4788)
To not modify or interrupt the system behavior around gas computation, this block will not include any sequenced transactions by setting noTxPool: true.

​
L1Block Deployment

The L1Block contract is upgraded to process the new Ecotone L1-data-fee parameters and L1 blob base-fee. A deposit transaction is derived with the following attributes:
  • from: 0x4210000000000000000000000000000000000000
  • to: null
  • mint: 0
  • value: 0
  • gasLimit: 375,000
  • data: 0x60806040523480156100105... (full bytecode)
  • sourceHash: 0x877a6077205782ea15a6dc8699fa5ebcec5e0f4389f09cb8eda09488231346f8, computed with the “Upgrade-deposited” type, with `intent = “Ecotone: L1 Block Deployment”
This results in the Ecotone L1Block contract being deployed to 0x07dbe8500fc591d1852B76feE44d5a05e13097Ff, to verify: 
cast compute-address --nonce=0 0x4210000000000000000000000000000000000000
Computed Address: 0x07dbe8500fc591d1852B76feE44d5a05e13097Ff
Verify sourceHash: 
cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Ecotone: L1 Block Deployment"))
# 0x877a6077205782ea15a6dc8699fa5ebcec5e0f4389f09cb8eda09488231346f8
Verify data: 
git checkout 5996d0bc1a4721f2169ba4366a014532f31ea932
pnpm clean && pnpm install && pnpm build
jq -r ".bytecode.object" packages/contracts-bedrock/forge-artifacts/L1Block.sol/L1Block.json
This transaction MUST deploy a contract with the following code hash 0xc88a313aa75dc4fbf0b6850d9f9ae41e04243b7008cf3eadb29256d4a71c1dfd.

​
GasPriceOracle Deployment

The GasPriceOracle contract is upgraded to support the new Ecotone L1-data-fee parameters. Post fork this contract will use the blob base fee to compute the gas price for L1-data-fee transactions. A deposit transaction is derived with the following attributes:
  • from: 0x4210000000000000000000000000000000000001
  • to: null,
  • mint: 0
  • value: 0
  • gasLimit: 1,000,000
  • data: 0x60806040523480156100... (full bytecode)
  • sourceHash: 0xa312b4510adf943510f05fcc8f15f86995a5066bd83ce11384688ae20e6ecf42 computed with the “Upgrade-deposited” type, with `intent = “Ecotone: Gas Price Oracle Deployment”
This results in the Ecotone GasPriceOracle contract being deployed to 0xb528D11cC114E026F138fE568744c6D45ce6Da7A, to verify: 
cast compute-address --nonce=0 0x4210000000000000000000000000000000000001
Computed Address: 0xb528D11cC114E026F138fE568744c6D45ce6Da7A
Verify sourceHash: 
❯ cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Ecotone: Gas Price Oracle Deployment"))
# 0xa312b4510adf943510f05fcc8f15f86995a5066bd83ce11384688ae20e6ecf42
Verify data: 
git checkout 5996d0bc1a4721f2169ba4366a014532f31ea932
pnpm clean && pnpm install && pnpm build
jq -r ".bytecode.object" packages/contracts-bedrock/forge-artifacts/GasPriceOracle.sol/GasPriceOracle.json
This transaction MUST deploy a contract with the following code hash 0x8b71360ea773b4cfaf1ae6d2bd15464a4e1e2e360f786e475f63aeaed8da0ae5.

​
L1Block Proxy Update

This transaction updates the L1Block Proxy ERC-1967 implementation slot to point to the new L1Block deployment. A deposit transaction is derived with the following attributes:
  • from: 0x0000000000000000000000000000000000000000
  • to: 0x4200000000000000000000000000000000000015 (L1Block Proxy)
  • mint: 0
  • value: 0
  • gasLimit: 50,000
  • data: 0x3659cfe600000000000000000000000007dbe8500fc591d1852b76fee44d5a05e13097ff
  • sourceHash: 0x18acb38c5ff1c238a7460ebc1b421fa49ec4874bdf1e0a530d234104e5e67dbc computed with the “Upgrade-deposited” type, with `intent = “Ecotone: L1 Block Proxy Update”
Verify data: 
cast concat-hex $(cast sig "upgradeTo(address)") $(cast abi-encode "upgradeTo(address)" 0x07dbe8500fc591d1852B76feE44d5a05e13097Ff)
0x3659cfe600000000000000000000000007dbe8500fc591d1852b76fee44d5a05e13097ff
Verify sourceHash: 
cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Ecotone: L1 Block Proxy Update"))
# 0x18acb38c5ff1c238a7460ebc1b421fa49ec4874bdf1e0a530d234104e5e67dbc

​
GasPriceOracle Proxy Update

This transaction updates the GasPriceOracle Proxy ERC-1967 implementation slot to point to the new GasPriceOracle deployment. A deposit transaction is derived with the following attributes:
  • from: 0x0000000000000000000000000000000000000000
  • to: 0x420000000000000000000000000000000000000F (Gas Price Oracle Proxy)
  • mint: 0
  • value: 0
  • gasLimit: 50,000
  • data: 0x3659cfe6000000000000000000000000b528d11cc114e026f138fe568744c6d45ce6da7a
  • sourceHash: 0xee4f9385eceef498af0be7ec5862229f426dec41c8d42397c7257a5117d9230a computed with the “Upgrade-deposited” type, with intent = "Ecotone: Gas Price Oracle Proxy Update"
Verify data: 
cast concat-hex $(cast sig "upgradeTo(address)") $(cast abi-encode "upgradeTo(address)" 0xb528D11cC114E026F138fE568744c6D45ce6Da7A)
0x3659cfe6000000000000000000000000b528d11cc114e026f138fe568744c6d45ce6da7a
Verify sourceHash: 
cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Ecotone: Gas Price Oracle Proxy Update"))
# 0xee4f9385eceef498af0be7ec5862229f426dec41c8d42397c7257a5117d9230a

​
GasPriceOracle Enable Ecotone

This transaction informs the GasPriceOracle to start using the Ecotone gas calculation formula. A deposit transaction is derived with the following attributes:
  • from: 0xDeaDDEaDDeAdDeAdDEAdDEaddeAddEAdDEAd0001 (Depositer Account)
  • to: 0x420000000000000000000000000000000000000F (Gas Price Oracle Proxy)
  • mint: 0
  • value: 0
  • gasLimit: 80,000
  • data: 0x22b90ab3
  • sourceHash: 0x0c1cb38e99dbc9cbfab3bb80863380b0905290b37eb3d6ab18dc01c1f3e75f93, computed with the “Upgrade-deposited” type, with `intent = “Ecotone: Gas Price Oracle Set Ecotone”
Verify data: 
cast sig "setEcotone()"
0x22b90ab3
Verify sourceHash: 
cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Ecotone: Gas Price Oracle Set Ecotone"))
# 0x0c1cb38e99dbc9cbfab3bb80863380b0905290b37eb3d6ab18dc01c1f3e75f93

​
Beacon block roots contract deployment (EIP-4788)

EIP-4788 introduces a “Beacon block roots” contract, that processes and exposes the beacon-block-root values. at address BEACON_ROOTS_ADDRESS = 0x000F3df6D732807Ef1319fB7B8bB8522d0Beac02. For deployment, EIP-4788 defines a pre-EIP-155 legacy transaction, sent from a key that is derived such that the transaction signature validity is bound to message-hash, which is bound to the input-data, containing the init-code. However, this type of transaction requires manual deployment and gas-payments. And since the processing is an integral part of the chain processing, and has to be repeated for Base, the deployment is approached differently here. Some chains may already have a user-submitted instance of the EIP-4788 transaction. This is cryptographically guaranteed to be correct, but may result in the upgrade transaction deploying a second contract, with the next nonce. The result of this deployment can be ignored. A Deposit transaction is derived with the following attributes:
  • from: 0x0B799C86a49DEeb90402691F1041aa3AF2d3C875, as specified in the EIP.
  • to: null
  • mint: 0
  • value: 0
  • gasLimit: 0x3d090, as specified in the EIP.
  • isCreation: true
  • data: 0x60618060095f395ff33373fffffffffffffffffffffffffffffffffffffffe14604d57602036146024575f5ffd5b5f35801560495762001fff810690815414603c575f5ffd5b62001fff01545f5260205ff35b5f5ffd5b62001fff42064281555f359062001fff015500
  • isSystemTx: false, even the system-generated transactions spend gas.
  • sourceHash: 0x69b763c48478b9dc2f65ada09b3d92133ec592ea715ec65ad6e7f3dc519dc00c, computed with the “Upgrade-deposited” type, with intent = "Ecotone: beacon block roots contract deployment"
The contract address upon deployment is computed as rlp([sender, nonce]), which will equal:
  • BEACON_ROOTS_ADDRESS if deployed
  • a different address (0xE3aE1Ae551eeEda337c0BfF6C4c7cbA98dce353B) if nonce = 1: when a user already submitted the EIP transaction before the upgrade.
Verify BEACON_ROOTS_ADDRESS: 
cast compute-address --nonce=0 0x0B799C86a49DEeb90402691F1041aa3AF2d3C875
# Computed Address: 0x000F3df6D732807Ef1319fB7B8bB8522d0Beac02
Verify sourceHash: 
cast keccak $(cast concat-hex 0x0000000000000000000000000000000000000000000000000000000000000002 $(cast keccak "Ecotone: beacon block roots contract deployment"))
# 0x69b763c48478b9dc2f65ada09b3d92133ec592ea715ec65ad6e7f3dc519dc00c