FieldElement (Javadocs [I2P+ 2.13.0+]

java.lang.Object
- net.i2p.crypto.eddsa.math.FieldElement

All Implemented Interfaces:
Serializable
Direct Known Subclasses:
BigIntegerFieldElement, Ed25519FieldElement
```
public abstract class FieldElement
extends Object
implements Serializable
```
Represents an element in a finite field of order $2^{b}-3$. Note: concrete subclasses must implement hashCode() and equals()
See Also:
Serialized Form

Field Summary
Fields
Modifier and Type Field and Description
protected Field f
The field this element belongs to

Fields
Modifier and Type	Field and Description
`protected Field`	`f` The field this element belongs to

Constructor Summary
Constructors
Constructor and Description
FieldElement(Field f)
Creates a new field element in the specified field.

Constructors
Constructor and Description
`FieldElement(Field f)` Creates a new field element in the specified field.

Method Summary

All Methods Instance Methods Abstract Methods Concrete Methods
Modifier and Type	Method and Description
`abstract FieldElement`	`add(FieldElement val)` Adds another field element to this one.
`FieldElement`	`addOne()` Adds one to this field element.
`abstract FieldElement`	`cmov(FieldElement val, int b)` Conditional move - sets this element to val if b is 1, otherwise leaves it unchanged.
`FieldElement`	`divide(FieldElement val)` Divides this field element by another one.
`abstract FieldElement`	`invert()` Computes the multiplicative inverse of this field element.
`boolean`	`isNegative()` Checks if this field element is negative.
`abstract boolean`	`isNonZero()` Checks if this field element is non-zero.
`abstract FieldElement`	`multiply(FieldElement val)` Multiplies this field element by another one.
`abstract FieldElement`	`negate()` Negates this field element.
`abstract FieldElement`	`pow22523()` Raises this field element to the power of $2^{252} - 3$.
`abstract FieldElement`	`square()` Squares this field element.
`abstract FieldElement`	`squareAndDouble()` Squares this field element and doubles the result.
`abstract FieldElement`	`subtract(FieldElement val)` Subtracts another field element from this one.
`FieldElement`	`subtractOne()` Subtracts one from this field element.
`byte[]`	`toByteArray()` Encode a FieldElement in its $(b-1)$-bit encoding.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - f
```
protected final Field f
```
    The field this element belongs to
- Constructor Detail
  - FieldElement
```
public FieldElement(Field f)
```
    Creates a new field element in the specified field.
    Parameters:
    f - the field this element belongs to
    Throws:
    IllegalArgumentException - if f is null
- Method Detail
  - add
```
public abstract FieldElement add(FieldElement val)
```
    Adds another field element to this one.
    Parameters:
    val - the field element to add
    Returns:
    the sum of this element and val
  - addOne
```
public FieldElement addOne()
```
    Adds one to this field element.
    Returns:
    this element plus one
  - cmov
```
public abstract FieldElement cmov(FieldElement val,
                                  int b)
```
    Conditional move - sets this element to val if b is 1, otherwise leaves it unchanged.
    Parameters:
    val - the field element to potentially assign
    b - the condition: 1 means assign val, 0 means keep this element
    Returns:
    this element, potentially modified
  - divide
```
public FieldElement divide(FieldElement val)
```
    Divides this field element by another one.
    Parameters:
    val - the divisor
    Returns:
    this element divided by val
  - invert
```
public abstract FieldElement invert()
```
    Computes the multiplicative inverse of this field element.
    Returns:
    the multiplicative inverse of this element
    Throws:
    ArithmeticException - if this element is zero
  - isNegative
```
public boolean isNegative()
```
    Checks if this field element is negative. Negative is defined as the least significant bit being 1.
    Returns:
    true if this element is negative, false otherwise
  - isNonZero
```
public abstract boolean isNonZero()
```
    Checks if this field element is non-zero.
    Returns:
    true if this element is not equal to zero, false otherwise
  - multiply
```
public abstract FieldElement multiply(FieldElement val)
```
    Multiplies this field element by another one.
    Parameters:
    val - the multiplier
    Returns:
    the product of this element and val
  - negate
```
public abstract FieldElement negate()
```
    Negates this field element.
    Returns:
    the negation of this element
  - pow22523
```
public abstract FieldElement pow22523()
```
    Raises this field element to the power of $2^{252} - 3$.
    Returns:
    this element raised to the power of $2^{252} - 3$
  - square
```
public abstract FieldElement square()
```
    Squares this field element.
    Returns:
    this element squared
  - squareAndDouble
```
public abstract FieldElement squareAndDouble()
```
    Squares this field element and doubles the result.
    Returns:
    (this element squared) * 2
  - subtract
```
public abstract FieldElement subtract(FieldElement val)
```
    Subtracts another field element from this one.
    Parameters:
    val - the field element to subtract
    Returns:
    the difference of this element and val
  - subtractOne
```
public FieldElement subtractOne()
```
    Subtracts one from this field element.
    Returns:
    this element minus one
  - toByteArray
```
public byte[] toByteArray()
```
    Encode a FieldElement in its $(b-1)$-bit encoding.
    Returns:
    the $(b-1)$-bit encoding of this FieldElement

Class FieldElement

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

f

Constructor Detail

FieldElement

Method Detail

add

addOne

cmov

divide

invert

isNegative

isNonZero

multiply

negate

pow22523

square

squareAndDouble

subtract

subtractOne

toByteArray