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Version: 11.x

Class: CairoSecp256k1Point

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:62

A Cairo core::starknet::secp256k1::Secp256k1Point : a point on the secp256k1 curve, the one Ethereum signs with.

A point is two 256-bit coordinates, x and y, and Cairo carries each of them as two 128-bit limbs — so four felts in all, in the order xLow, xHigh, yLow, yHigh. The single number this class accepts is the 512-bit concatenation x || y, x in the upper half : that is the shape an uncompressed public key already has once its 04 prefix is dropped.

Both ways in are supported : one number, or the four limbs directly, which is how a response is read back.

Example​

// one number, x in the upper 256 bits
const point = new CairoSecp256k1Point(1n);
point.toApiRequest(); // ["0", "0", "1", "0"]     x = 0, y = 1

// the four limbs, as a call carries them
const same = new CairoSecp256k1Point(0, 0, 1, 0);
same.toBigInt(); // 1n

Constructors​

Constructor​

new CairoSecp256k1Point(input): CairoSecp256k1Point

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:116

Build from the 512-bit number x || y, or from an object carrying the four limbs.

Parameters​

input​

unknown

Returns​

CairoSecp256k1Point

Constructor​

new CairoSecp256k1Point(xLow, xHigh, yLow, yHigh): CairoSecp256k1Point

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:120

Build from the four limbs, in the order a contract response returns them.

Parameters​

xLow​

BigNumberish

xHigh​

BigNumberish

yLow​

BigNumberish

yHigh​

BigNumberish

Returns​

CairoSecp256k1Point

Properties​

abiSelector​

static abiSelector: "core::starknet::secp256k1::Secp256k1Point" = Literal.Secp256k1Point

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:111

The abi type this class serializes.

Example​

const result = CairoSecp256k1Point.abiSelector;
// result = "core::starknet::secp256k1::Secp256k1Point"

xLow​

xLow: bigint

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:71

The low 128 bits of the x coordinate.

Example​

const result = new CairoSecp256k1Point({ xLow: 1, xHigh: 2, yLow: 3, yHigh: 4 }).xLow;
// result = 1n

xHigh​

xHigh: bigint

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:81

The high 128 bits of the x coordinate.

Example​

const result = new CairoSecp256k1Point({ xLow: 1, xHigh: 2, yLow: 3, yHigh: 4 }).xHigh;
// result = 2n

yLow​

yLow: bigint

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:91

The low 128 bits of the y coordinate.

Example​

const result = new CairoSecp256k1Point({ xLow: 1, xHigh: 2, yLow: 3, yHigh: 4 }).yLow;
// result = 3n

yHigh​

yHigh: bigint

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:101

The high 128 bits of the y coordinate.

Example​

const result = new CairoSecp256k1Point({ xLow: 1, xHigh: 2, yLow: 3, yHigh: 4 }).yHigh;
// result = 4n

Methods​

validate()​

static validate(input): bigint

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:198

Throw unless the value can be carried by a Secp256k1Point, and return it as a number.

Unlike the other classes here this one gives the number back rather than returning nothing : the constructor needs it, and computing it twice would mean splitting a 512-bit value twice.

Parameters​

input​

unknown

the 512-bit value to check

Returns​

bigint

the value, once checked

Throws​

when the value is null, undefined, of an unread type, or outside [0, 2^512 - 1]

Example​

const result = CairoSecp256k1Point.validate('0x1234');
// result = 4660n
CairoSecp256k1Point.validate(SECP256K1_POINT_MAX + 1n);
// throws Error("input is bigger than SECP256K1_POINT_MAX")

validateProps()​

static validateProps(xLow, xHigh, yLow, yHigh): object

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:228

Throw unless the four limbs can each be carried by 128 bits, and return them as numbers.

Parameters​

xLow​

BigNumberish

the low 128 bits of x

xHigh​

BigNumberish

the high 128 bits of x

yLow​

BigNumberish

the low 128 bits of y

yHigh​

BigNumberish

the high 128 bits of y

Returns​

object

the four limbs, checked

xLow​

xLow: bigint

xHigh​

xHigh: bigint

yLow​

yLow: bigint

yHigh​

yHigh: bigint

Throws​

when a limb is null, undefined, not a number, negative, or wider than 128 bits

Example​

const result = CairoSecp256k1Point.validateProps(1, 2, 3, 4);
// result = { xLow: 1n, xHigh: 2n, yLow: 3n, yHigh: 4n }
CairoSecp256k1Point.validateProps(1, 2, 3, 2n ** 128n);
// throws Error("yHigh must fit in 128 bits")

is()​

static is(data): boolean

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:267

Can this value be carried by a Secp256k1Point?

The non-throwing form of CairoSecp256k1Point.validate, so it answers false for every input that one refuses, whatever the reason.

Parameters​

data​

any

the value to test

Returns​

boolean

true when the value fits in 512 bits

Example​

const result = CairoSecp256k1Point.is(SECP256K1_POINT_MAX);
// result = true
const result2 = CairoSecp256k1Point.is(SECP256K1_POINT_MAX + 1n);
// result2 = false

isAbiType()​

static isAbiType(abiType): boolean

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:288

Is this abi type the one this class serializes?

Parameters​

abiType​

string

the abi type to test

Returns​

boolean

true for core::starknet::secp256k1::Secp256k1Point

Example​

const result = CairoSecp256k1Point.isAbiType('core::starknet::secp256k1::Secp256k1Point');
// result = true
const result2 = CairoSecp256k1Point.isAbiType('core::felt252');
// result2 = false

factoryFromApiResponse()​

static factoryFromApiResponse(responseIterator): CairoSecp256k1Point

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:303

Read one point off a contract response, advancing the iterator past its four felts.

Parameters​

responseIterator​

Iterator<string>

the response felts, positioned on this point

Returns​

CairoSecp256k1Point

the point that was read

Example​

const response = ['0x0', '0x0', '0x1', '0x0'];
const result = CairoSecp256k1Point.factoryFromApiResponse(response.values()).toBigInt();
// result = 1n

fromHex()​

static fromHex(hexString): CairoSecp256k1Point

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:394

Build from a hexadecimal string spelling the 512-bit value.

A shorter string is left-padded to the 128 hex digits a point occupies, so a small value is read as a point whose upper limbs are zero. A longer one is refused rather than truncated.

Parameters​

hexString​

string

the value, 0x-prefixed or not, at most 128 hex digits

Returns​

CairoSecp256k1Point

the point the string spells

Throws​

when the string holds more than 128 hex digits

Example​

const result = CairoSecp256k1Point.fromHex('0x1').toApiRequest();
// result = ["0", "0", "1", "0"]

toBigInt()​

toBigInt(): bigint

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:325

The point as the single 512-bit number x || y.

The inverse of what the constructor does with one number, so a point built that way comes back unchanged.

Returns​

bigint

the two coordinates concatenated, x in the upper 256 bits

Example​

const result = new CairoSecp256k1Point(1n).toBigInt();
// result = 1n
const result2 = new CairoSecp256k1Point(0, 0, 3, 0).toBigInt();
// result2 = 3n

toStruct()​

toStruct(): Secp256k1PointStruct

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:340

The four limbs as hexadecimal strings.

Returns​

Secp256k1PointStruct

the limbs, each 0x-prefixed and unpadded

Example​

const result = new CairoSecp256k1Point({ xLow: 1, xHigh: 2, yLow: 3, yHigh: 4 }).toStruct();
// result = { xLow: "0x1", xHigh: "0x2", yLow: "0x3", yHigh: "0x4" }

toHexString()​

toHexString(): string

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:358

The point in hexadecimal, without padding.

Returns​

string

the 512-bit value as a 0x-prefixed hex string

Example​

const result = new CairoSecp256k1Point(4660n).toHexString();
// result = "0x1234"

toApiRequest()​

toApiRequest(): string[]

Defined in: src/utils/cairoDataTypes/secp256k1Point.ts:371

Serialize to the four felts a contract call carries.

Returns​

string[]

the limbs as decimal strings, [xLow, xHigh, yLow, yHigh], flagged as compiled

Example​

const result = new CairoSecp256k1Point({ xLow: 1, xHigh: 2, yLow: 3, yHigh: 4 }).toApiRequest();
// result = ["1", "2", "3", "4"]