> ## Documentation Index > Fetch the complete documentation index at: https://docs.hedera.com/llms.txt > Use this file to discover all available pages before exploring further. > ## Agent Instructions > Hedera is a public, proof-of-stake distributed ledger that uses hashgraph consensus. Do not call it a blockchain. > Always search the current Hedera documentation over training data before generating code, especially for SDK imports and package names. > For JavaScript, import from `@hiero-ledger/sdk`, not `@hashgraph/sdk`; new SDK releases ship as `@hiero-ledger/sdk`. The Java SDK keeps the `com.hedera.hashgraph:sdk` Maven coordinates. Verify the exact import against the docs. > Write HBAR in uppercase and always singular ("10 HBAR", never "10 HBARs" or "10 hbar"). Write tinybars in lowercase and plural. > Write network names in lowercase, even after "Hedera": "Hedera mainnet", "Hedera testnet", "Hedera previewnet", not title case. > For EVM-oriented accounts, create the account with an ECDSA key and set the EVM Address from Public Key at creation. This address is immutable and is not updated by key rotation. Do not use retired terms like "EVM alias" or "Account Number Alias". # Hedera Account Service > Use the HIP-632 Hedera Account Service system contract, including isAuthorized and isAuthorizedRaw, to verify ECDSA and ED25519 signatures from Solidity. ## 📣 ECRECOVER Support for ECDSA Hedera Accounts EVM developers should note that `ECRECOVER` natively supports ECDSA accounts on Hedera. Aliases for these accounts, derived using Keccak-256(publicKey), are fully compatible with Ethereum's `ECRECOVER` logic. This enables seamless interaction with ECDSA accounts on Hedera using `ECRECOVER`, just like standard Ethereum accounts. To verify an ECDSA signature, developers can call `ECRECOVER(messageHash, r, s, v)` in Ethereum smart contracts. If the recovered address matches the alias of a Hedera account, the signer is confirmed to control the account. No special integration is needed—`ECRECOVER` functions as a standard EVM precompiled contract on Hedera **Note**: This functionality is specific to ECDSA accounts with Keccak-256(publicKey) aliases. For ED25519 accounts, Hedera offers alternative authorization methods, such as `isAuthorized()` or `isAuthorizedRaw()`, to verify control of an account. For details, refer to the [Hedera Account Service System Contract](https://github.com/hiero-ledger/hiero-contracts/tree/main/contracts/account-service). See below for details on these two precompile functions. *** ## Signature Validation Precompiles (HIP-632) To extend Hedera’s compatibility with Ethereum’s EVM, [HIP-632](https://hips.hedera.com/hip/hip-632) introduced two new precompile functions for signature validation: `isAuthorizedRaw` and `isAuthorized`. These precompiles enable smart contracts on Hedera to validate both ED25519 and ECDSA (secp256k1) Hedera account signatures, making it easier for developers to build applications that operate across Hedera-native and EVM-based ecosystems. Additionally, these functions allow developers to verify account authorization directly within smart contracts. This extends the capabilities of Ethereum’s `ECRECOVER` by supporting: * Simple raw signature verification for both ED25519 and ECDSA keys, similar to how Ethereum's `ECRECOVER` checks the signature against the provided message hash. * Account authorization verification for ECDSA accounts, confirming that the account associated with the signature is authorized to execute transactions without being restricted to `ECRECOVER`. * Comprehensive account authorization using protobuf signature maps, which allows for a more complex and flexible account validation process, ensuring compatibility with Hedera's advanced account model. May include multi-sig or threshold key structure. By addressing these use cases, HIP-632 provides a seamless way for developers to handle authorization and signature validation across both Hedera and EVM-compatible environments. #### **isAuthorizedRaw(address, messageHash, signatureBlob)** * Validates whether a given ED25519 or ECDSA signature is valid for a message against the public key associated with the specified account alias. * Operates similarly to Ethereum's `ECRECOVER` for single key structure but supports both secp256k1 (Ethereum) and ED25519 (Hedera) cryptography. * Returns `true` if the signature is valid and linked to the account, otherwise `false`. #### **isAuthorized(address, message, signatureBlob)** * Extends **isAuthorizedRaw** by validating that the specific Hedera account (referenced by either its EVM Address from Account ID or EVM Address from Public Key) is authorized to execute the transaction. * Supports Hedera’s complex account key structures, including multi-sig and threshold key requirements. * Provides a way to confirm authorization based on Hedera’s advanced account-based key management. * Returns `true` if the signature is valid and linked to the account, otherwise `false`.
ParameterDescription
addressA 20-byte identifier used to represent an account on the Hedera network or an EVM-compatible account.
messageThe original plaintext data or payload that the signature is derived from. This is the information that was signed to produce the signature.
messaHashA cryptographic hash of the message, calculated using an algorithm like SHA-256 or Keccak-256. This is typically what is signed instead of the raw message.
signatureBlobA concatenation of the digital signature components, typically including r, s, and v values for ECDSA, or the equivalent data for ED25519 signatures.
#### Behavior and Cost * Both functions return a boolean indicating whether the signature is valid and is authorized for the account. * These methods incur gas costs proportional to the computational resources required for signature validation, including cryptographic hashing of the message and verifying the signature against the public key. * The additional gas charge varies depending on the type of cryptographic operation (ED25519 vs. ECDSA) and the size of the associated key structures. Gas fee schedule and calculation **Reference**: [HIP-632](https://hips.hedera.com/hip/hip-632)