Interface SecpFieldElement

All Known Implementing Classes:

SecpFieldElementImpl

public interface SecpFieldElement

A number that is a valid element of the P256K1 field. We use this instead of BigInteger so we can use a fixed-length, unsigned representation for simplicity and performance.

Method Summary

Modifier and Type	Method	Description
static BigInteger	checkInRange(BigInteger e)	Throw IllegalArgumentException if an integer is not in the inclusive range 0 to P - 1, where P is the prime of the SECP256K1 prime finite field.
static boolean	isInRange(BigInteger e)	Check if an integer is in the inclusive range 0 to P - 1, where P is the prime of the SECG P256K1 prime finite field.
boolean	isOdd()	Get the parity of the field value
static SecpFieldElement	of(byte[] bytes)	Construct a field element from a big-endian byte-array of 32 bytes
static SecpFieldElement	of(BigInteger i)	Construct a SecpFieldElement from a BigInteger
byte[]	serialize()	Get serialized (big-endian) field element (32 bytes unsigned)
BigInteger	toBigInteger()	Get the field element as a BigInteger

Method Details

toBigInteger

BigInteger toBigInteger()

Get the field element as a BigInteger

Returns:

field element value

serialize

byte[] serialize()

Get serialized (big-endian) field element (32 bytes unsigned)

Returns:

serialized field element

isOdd

boolean isOdd()

Get the parity of the field value

Returns:

true if odd, false if even

of

static SecpFieldElement of(BigInteger i)

Construct a SecpFieldElement from a BigInteger

Parameters:

i - integer

Returns:

valid element

of

static SecpFieldElement of(byte[] bytes)

Construct a field element from a big-endian byte-array of 32 bytes

Parameters:

bytes - array containing a valid field element

Returns:

field element

isInRange

static boolean isInRange(BigInteger e)

Check if an integer is in the inclusive range 0 to P - 1, where P is the prime of the SECG P256K1 prime finite field.

Parameters:

e - A possible field element to validate

Returns:

true if valid

checkInRange

static BigInteger checkInRange(BigInteger e)

Throw IllegalArgumentException if an integer is not in the inclusive range 0 to P - 1, where P is the prime of the SECP256K1 prime finite field.

Parameters:

e - unvalidated integer

Returns:

a validated integer