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Cryptographic data types

Tezos provides hash functions for cryptographic purposes.

By default, use BLAKE2B, which computes a cryptographic hash of the value contents using the Blake2b-256 cryptographic hash function.

These other hash functions are available:

  • KECCAK: Compute a cryptographic hash of the value contents using the Keccak-256 cryptographic hash function.
  • SHA256: Compute a cryptographic hash of the value contents using the Sha256 cryptographic hash function.
  • SHA512: Compute a cryptographic hash of the value contents using the Sha512 cryptographic hash function.
  • SHA3: Compute a cryptographic hash of the value contents using the SHA3-256 cryptographic hash function.

Checking signatures​

Tezos lets you check that a given piece of data, a sequence of bytes in a bytes data type, has been signed by the holder of the private key corresponding to a given public key.

The primitive CHECK_SIGNATURE takes as parameters the sequence of bytes, the signature and the public key, and returns a Boolean that indicates if the signature is indeed a signature of that sequence of bytes, by the holder of ths key.

BLS12-381 primitives​

BLS12-381 is the name of an elliptic curve, a cryptographic primitive that can be used for digital signatures and zero-knowledge proofs.

It has the particularity of being pairing-friendly, which makes it possible to create short digital signatures that can be efficiently aggregated. It can also be used for identity-based cryptography, single-round multi-party key exchanges, or and efficient polynomial commitment schemes such as KZG commitments.

Implementation details​

Time-locks​

A timelock is a cryptographic primitive that can be used as part of a commit-and-reveal scheme, to provide a guarantee that the information associated to the commit is eventually revealed.

For information about using time-locks, see Timelocks.

Implementation details​

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