HarryR

field_modulus = 4002409555221667393417789825735904156556882819939007885332058136124031650490837864442687629129015664037894272559787
desired_curve_order = 52435875175126190479447740508185965837690552500527637822603658699938581184513

Fp = GF(field_modulus)

PARAM_A4 = 0
PARAM_A6 = 4

E = EllipticCurve(Fp, [PARAM_A4, PARAM_A6])
E_order = E.order()

agolajko

Returning fp for calling functions in Cairo loops

Getting loops to work in Starknet's Cairo can be complicated. Currently you need to fiddle around a lot with ap, fp and pc even for mundane computations. Further, when calling a function within a loop tempvar will be dereferenced causing the loop to fail. For example the following code will not run:

tempvar iterator=10
tempvar sum=0

loop_start:
 let (local a, local b)=div (10, 5)

milancermak

This gist contains the following Solidity code translated to Cairo:

uint256 x = 20
uint256 out = uint256(keccak256(abi.encode(x)))

It uses the keccak256 implementation from starknet-l2-storage-verifier lib. The function deals with all the peculiarities of the necessary conversion (endianness, splitting of Uint256 to four 64-bit words and back again). There's also two helper python function to illustrate how to pass arguments in and how to deal with the result.

nikkolasg

*
	Verifying Drands BLS12-381 Signatures in GoLang

	Using the following randomness payloads:
	{
		"round": 1657526,
		"randomness": "58b26a65bf4032555748c2949311abb2c4f580e7d7d7f70b13d0533b793c4c7d",
		"signature": "8434e45af135f363b04b792c1d77b83e36ef66829b0a09f7eed058103429f0e7f759ebf6d001cf73e9138f5b7a7f04b602c4167390c323432562d6367e09169422707a9778eba260c4d6434ea5e1d2c81462a4e3cd430990aebc593f4ae7517c",
		"previous_signature": "ab9e594732265dd737b536a144fb955bfeabe929116fc78f7bb740de3f43629691cabcec507eeb39a98d51be11942cf4062b0a38dd1be18be5e23bea7efd3935bb23032dba4da0374899e583feb937119f33f6b645048e0e91cde0de00e3e9ee"
	},