What is a Public Key Hash (PKH)?
- Last Updated: August 13, 2026
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Definition
A Public Key Hash (PKH) is a cryptographic hash of a public key used to provide a compact and secure representation of the public key in cryptocurrency transactions.
Additional Explanation
A public key hash is created by hashing a public key first with SHA-256 and then with RIPEMD-160. The resulting hash is then encoded into a public address using formats like Base58Check, which includes the public key hash, a version byte, and a checksum. It is possible to decode and obtain the public key hash from the public address, which is then used in transactions.
Public key hashes offer several benefits. They are more compact (20 bytes) than public keys (33 or 65), making them more efficient to store and transmit. Using a public key hash also adds an extra layer of security, as the public key is exposed once the funds are spent, reducing the attack surface.
In cryptocurrency transactions, the public key hash specifies the recipient’s address. In Pay-to-PubKey-Hash (P2PKH) transactions, the locking script includes the public key hash, ensuring that only the owner of the corresponding private key can unlock and spend the funds. When paying the funds, the recipient provides an unlocking script that includes the public key and a signature, verified against the public key hash in the locking script.
To enhance privacy, it is recommended to use a new public key and address for each transaction, avoiding reuse. Public Key Hashes (PKH) play a crucial role in cryptocurrency transactions by providing a secure and efficient way to specify recipient addresses, ensuring privacy and security while facilitating the compact representation of public keys. From the public address shared by the recipient, the public key hash can be derived and used as the destination in transactions.
Frequently Asked Questions (FAQ)
A PKH is generated by applying a cryptographic hash function (such as SHA-256 followed by RIPEMD-160 in Bitcoin) to a public key.
This process condenses the public key into a shorter, fixed-length hash, which enhances security and simplifies transaction address formats.
The main uses of a PKH include creating blockchain addresses for receiving funds, enhancing the security of public keys by hashing them and reducing the data size for transactions.
PKHs are integral to the functionality of cryptocurrencies like Bitcoin, where they form part of the address used in transactions.
A PKH is a hashed public key version, providing a shorter and more secure representation.
While a public key is used to verify digital signatures and encrypt data, a PKH generates addresses and ensures that the public key itself is not exposed directly, adding an extra layer of security.
A PKH is used instead of the public key to enhance security and privacy.
Hashing the public key makes it harder for attackers to reverse-engineer it or launch certain cryptographic attacks.
Additionally, PKHs create shorter and more user-friendly addresses for blockchain transactions.
In Bitcoin transactions, the PKH is used to generate a Bitcoin address.
When users want to receive Bitcoin, they share their Bitcoin address derived from the PKH.
During transaction validation, the blockchain network uses the PKH to verify that the correct public key is associated with the address.
No, a PKH cannot be reversed to obtain the original public key.
Hash functions used to generate PKHs are designed to be one-way, meaning they cannot be feasibly inverted.
This ensures the public key remains secure even if the PKH is publicly known.
A PKH enhances security by obscuring the public key through hashing.
This reduces the risk of certain cryptographic attacks that could target the public key directly.
Additionally, using PKHs in address generation ensures that the underlying public key is not immediately exposed if an address is compromised.
A PKH is derived from a public key and used to create standard blockchain addresses, while a Script Hash (SH) is derived from a locking script (or redeem script) and used in more complex transactions, such as multi-signature addresses.
SHs allow for more flexible and programmable transaction conditions than PKHs.
Users should store their private keys securely, as the PKH relies on the corresponding public key for transaction verification.
They should also be aware that losing access to the private key means losing control over the funds associated with the PKH. Therefore, it is crucial to use reputable wallets that manage PKHs correctly.
Yes, PKHs are used in various blockchain networks besides Bitcoin.
Many cryptocurrencies and blockchain platforms adopt similar principles of using hashed public keys to enhance security and create addresses.
While the specific hash functions and address formats may vary, the concept of using PKHs remains consistent across different networks.
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