Convert ETH Private Key To Public Key, or Address Online

notice: the tool is Open Source and running locally only

What is Ethereum Private Key

  • A private key in Ethereum is a secret number that allows user to access their funds. It is used to sign transactions and messages, which proves the ownership of the address.
  • Generation: Ethereum private key is generated using elliptic-curve cryptography, specifically the secp256k1 curve.
  • Security: The private key must remain confidential because anyone with access to it can control the funds.
  • Public Key Derivation: From the private key, a public key is derived, which in turn is used to generate an Ethereum address.
  • Usage: When you initiate a transaction, you sign it with your private key. This signature is used to verify that the transaction comes from the rightful owner.
  • Storage: It's need to store your private key securely, as losing it means losing access to your assets.

What is Ethereum Uncompressed Public Key

  • Definition: An uncompressed public key in Ethereum is derived from a private key using the secp256k1 elliptic curve. It includes both the x and y coordinates of a point on the curve, representing the public key.
  • Format: The uncompressed public key starts with the prefix 04, followed by the x coordinate and then the y coordinate. Each coordinate is 32 bytes long, making the total length of an uncompressed public key 65 bytes (including the prefix).
  • Usage: Uncompressed public keys were commonly used in earlier wallet software. However, they are larger in size compared to compressed public keys, which only include the x coordinate and a prefix to indicate the y coordinate.
  • Example:
    • Prefix: 04
    • X Coordinate: x-coordinate-here
    • Y Coordinate: y-coordinate-here
    • Full Key: 04|x-coordinate-here|y-coordinate-here
  • Compression: To reduce the size, a public key can be compressed, removing the y coordinate. The compressed format starts with either 02 or 03, depending on whether the y coordinate is even or odd, respectively.
  • Relevance: While uncompressed keys are still supported for backward compatibility, most modern Ethereum applications use compressed keys due to their smaller size and efficiency.

What is Ethereum Compressed Public Key

  • Definition: An uncompressed public key in Ethereum is derived from a private key using the secp256k1 elliptic curve. It includes both the x and y coordinates of a point on the curve, representing the public key.
  • Format: The uncompressed public key starts with the prefix 04, followed by the x coordinate and then the y coordinate. Each coordinate is 32 bytes long, making the total length of an uncompressed public key 65 bytes (including the prefix).
  • Usage: Uncompressed public keys were commonly used in earlier wallet software. However, they are larger in size compared to compressed public keys, which only include the x coordinate and a prefix to indicate the y coordinate.
  • Example:
    • Prefix: 04
    • X Coordinate: x-coordinate-here
    • Y Coordinate: y-coordinate-here
    • Full Key: 04|x-coordinate-here|y-coordinate-here
  • Compression: To reduce the size, a public key can be compressed, removing the y coordinate. The compressed format starts with either 02 or 03, depending on whether the y coordinate is even or odd, respectively.
  • Relevance: While uncompressed keys are still supported for backward compatibility, most modern Ethereum applications use compressed keys due to their smaller size and efficiency.

What is Ethereum address

  • Definition: An Ethereum address is a unique identifier that allows users to send, receive, and store Ether (ETH) and other tokens on the Ethereum network. It also serves as the interaction point for smart contracts.
  • Structure: An Ethereum address is a 42-character hexadecimal string that starts with '0x'. It is derived from the public key of an Ethereum account and is used to direct transactions.
  • Checksum: To prevent errors in address input, Ethereum uses a checksum mechanism where the case of the hexadecimal characters encodes redundancy checks. This is specified in EIP-55.
  • Example:
    • Non-checksummed: 0x6827b8f6cc60497d9bf5210d602c0ecafdf7c405
    • Checksummed: 0x6827b8F6Cc60497D9bF5210D602c0EcaFDF7C405
  • Usage: Users must provide their Ethereum address to receive funds or interact with decentralized applications (DApps). It is also used to view account balances and transaction history.
  • Security: It is crucial to keep your Ethereum address secure and private, as it is linked to your assets on the blockchain.
  • Best Practices: Always double-check addresses before sending transactions, use checksummed addresses to avoid errors, and consider using ENS (Ethereum Name Service) for a more human-readable address format.