Cryptographic Primitives

Algorand Smart Contracts support 4 cryptographic primitives, including 3 cryptographic hash functions and 1 digital signature verification. Each of these cryptographic primitives is associated with a cost, which is a number indicating its relative performance overhead comparing with simple TEAL operations such as addition and substraction. Simple TEAL opcodes have cost 1, and more advanced cryptographic operations have a larger cost. Below is how you express cryptographic primitives in PyTeal:

Operator

Cost

Description

Sha256(e)

35

SHA-256 hash function, produces 32 bytes

Keccak256(e)

130

Keccak-256 hash funciton, produces 32 bytes

Sha512_256(e)

45

SHA-512/256 hash function, produces 32 bytes

Ed25519Verify(d, s, p)

1900*

1 if s is the signature of d signed by private key p, else 0

* Ed25519Verify is only available in signature mode up to version 4 of TEAL. From version 5 upwards, Ed25519Verify can be used in any mode.

Note the cost amount is accurate for version 2 of TEAL and higher.

These cryptographic primitives cover the most used ones in blockchains and cryptocurrencies. For example, Bitcoin uses SHA-256 for creating Bitcoin addresses; Alogrand uses ed25519 signature scheme for authorization and uses SHA-512/256 hash function for creating contract account addresses from TEAL bytecode.