bigint-crypto-utils/docs/API.md

# bigint-crypto-utils

## Table of contents

### Functions

- [abs](API.md#abs)
- [bitLength](API.md#bitlength)
- [eGcd](API.md#egcd)
- [gcd](API.md#gcd)
- [isProbablyPrime](API.md#isprobablyprime)
- [lcm](API.md#lcm)
- [max](API.md#max)
- [min](API.md#min)
- [modInv](API.md#modinv)
- [modPow](API.md#modpow)
- [prime](API.md#prime)
- [primeSync](API.md#primesync)
- [randBetween](API.md#randbetween)
- [randBits](API.md#randbits)
- [randBitsSync](API.md#randbitssync)
- [randBytes](API.md#randbytes)
- [randBytesSync](API.md#randbytessync)
- [toZn](API.md#tozn)

## Functions

### abs

▸ **abs**(`a`: *number* \| *bigint*): *number* \| *bigint*

Absolute value. abs(a)==a if a>=0. abs(a)==-a if a<0

#### Parameters:

| Name | Type |
| :------ | :------ |
| `a` | *number* \| *bigint* |

**Returns:** *number* \| *bigint*

The absolute value of a

Defined in: node_modules/bigint-mod-arith/dist/esm/types/ts/abs.d.ts:8

___

### bitLength

▸ **bitLength**(`a`: *number* \| *bigint*): *number*

Returns the bitlength of a number

#### Parameters:

| Name | Type |
| :------ | :------ |
| `a` | *number* \| *bigint* |

**Returns:** *number*

The bit length

Defined in: node_modules/bigint-mod-arith/dist/esm/types/ts/bitLength.d.ts:7

___

### eGcd

▸ **eGcd**(`a`: *number* \| *bigint*, `b`: *number* \| *bigint*): Egcd

An iterative implementation of the extended euclidean algorithm or extended greatest common divisor algorithm.
Take positive integers a, b as input, and return a triple (g, x, y), such that ax + by = g = gcd(a, b).

**`throws`** {RangeError}
This excepction is thrown if a or b are less than 0

#### Parameters:

| Name | Type |
| :------ | :------ |
| `a` | *number* \| *bigint* |
| `b` | *number* \| *bigint* |

**Returns:** Egcd

A triple (g, x, y), such that ax + by = g = gcd(a, b).

Defined in: node_modules/bigint-mod-arith/dist/esm/types/ts/egcd.d.ts:18

___

### gcd

▸ **gcd**(`a`: *number* \| *bigint*, `b`: *number* \| *bigint*): *bigint*

Greatest-common divisor of two integers based on the iterative binary algorithm.

#### Parameters:

| Name | Type |
| :------ | :------ |
| `a` | *number* \| *bigint* |
| `b` | *number* \| *bigint* |

**Returns:** *bigint*

The greatest common divisor of a and b

Defined in: node_modules/bigint-mod-arith/dist/esm/types/ts/gcd.d.ts:9

___

### isProbablyPrime

▸ **isProbablyPrime**(`w`: *number* \| *bigint*, `iterations?`: *number*, `disableWorkers?`: *boolean*): *Promise*<boolean\>

The test first tries if any of the first 250 small primes are a factor of the input number and then passes several
iterations of Miller-Rabin Probabilistic Primality Test (FIPS 186-4 C.3.1)

**`throws`** {RangeError}
w MUST be >= 0

#### Parameters:

| Name | Type | Default value | Description |
| :------ | :------ | :------ | :------ |
| `w` | *number* \| *bigint* | - | A positive integer to be tested for primality |
| `iterations` | *number* | 16 | The number of iterations for the primality test. The value shall be consistent with Table C.1, C.2 or C.3 |
| `disableWorkers` | *boolean* | false | Disable the use of workers for the primality test |

**Returns:** *Promise*<boolean\>

A promise that resolves to a boolean that is either true (a probably prime number) or false (definitely composite)

Defined in: [src/ts/isProbablyPrime.ts:21](https://github.com/juanelas/bigint-crypto-utils/blob/5bba6de/src/ts/isProbablyPrime.ts#L21)

___

### lcm

▸ **lcm**(`a`: *number* \| *bigint*, `b`: *number* \| *bigint*): *bigint*

The least common multiple computed as abs(a*b)/gcd(a,b)

#### Parameters:

| Name | Type |
| :------ | :------ |
| `a` | *number* \| *bigint* |
| `b` | *number* \| *bigint* |

**Returns:** *bigint*

The least common multiple of a and b

Defined in: node_modules/bigint-mod-arith/dist/esm/types/ts/lcm.d.ts:8

___

### max

▸ **max**(`a`: *number* \| *bigint*, `b`: *number* \| *bigint*): *number* \| *bigint*

Maximum. max(a,b)==a if a>=b. max(a,b)==b if a<=b

#### Parameters:

| Name | Type |
| :------ | :------ |
| `a` | *number* \| *bigint* |
| `b` | *number* \| *bigint* |

**Returns:** *number* \| *bigint*

Maximum of numbers a and b

Defined in: node_modules/bigint-mod-arith/dist/esm/types/ts/max.d.ts:9

___

### min

▸ **min**(`a`: *number* \| *bigint*, `b`: *number* \| *bigint*): *number* \| *bigint*

Minimum. min(a,b)==b if a>=b. min(a,b)==a if a<=b

#### Parameters:

| Name | Type |
| :------ | :------ |
| `a` | *number* \| *bigint* |
| `b` | *number* \| *bigint* |

**Returns:** *number* \| *bigint*

Minimum of numbers a and b

Defined in: node_modules/bigint-mod-arith/dist/esm/types/ts/min.d.ts:9

___

### modInv

▸ **modInv**(`a`: *number* \| *bigint*, `n`: *number* \| *bigint*): *bigint*

Modular inverse.

**`throws`** {RangeError}
Excpeption thorwn when a does not have inverse modulo n

#### Parameters:

| Name | Type | Description |
| :------ | :------ | :------ |
| `a` | *number* \| *bigint* | The number to find an inverse for |
| `n` | *number* \| *bigint* | The modulo |

**Returns:** *bigint*

The inverse modulo n

Defined in: node_modules/bigint-mod-arith/dist/esm/types/ts/modInv.d.ts:12

___

### modPow

▸ **modPow**(`b`: *number* \| *bigint*, `e`: *number* \| *bigint*, `n`: *number* \| *bigint*): *bigint*

Modular exponentiation b**e mod n. Currently using the right-to-left binary method

**`throws`** {RangeError}
Excpeption thrown when n is not > 0

#### Parameters:

| Name | Type | Description |
| :------ | :------ | :------ |
| `b` | *number* \| *bigint* | base |
| `e` | *number* \| *bigint* | exponent |
| `n` | *number* \| *bigint* | modulo |

**Returns:** *bigint*

b**e mod n

Defined in: node_modules/bigint-mod-arith/dist/esm/types/ts/modPow.d.ts:13

___

### prime

▸ **prime**(`bitLength`: *number*, `iterations?`: *number*): *Promise*<bigint\>

A probably-prime (Miller-Rabin), cryptographically-secure, random-number generator.
The browser version uses web workers to parallelise prime look up. Therefore, it does not lock the UI
main process, and it can be much faster (if several cores or cpu are available).
The node version can also use worker_threads if they are available (enabled by default with Node 11 and
and can be enabled at runtime executing node --experimental-worker with node >=10.5.0).

**`throws`** {RangeError}
bitLength MUST be > 0

#### Parameters:

| Name | Type | Default value | Description |
| :------ | :------ | :------ | :------ |
| `bitLength` | *number* | - | The required bit length for the generated prime |
| `iterations` | *number* | 16 | The number of iterations for the Miller-Rabin Probabilistic Primality Test |

**Returns:** *Promise*<bigint\>

A promise that resolves to a bigint probable prime of bitLength bits.

Defined in: [src/ts/prime.ts:21](https://github.com/juanelas/bigint-crypto-utils/blob/5bba6de/src/ts/prime.ts#L21)

___

### primeSync

▸ **primeSync**(`bitLength`: *number*, `iterations?`: *number*): *bigint*

A probably-prime (Miller-Rabin), cryptographically-secure, random-number generator.
The sync version is NOT RECOMMENDED since it won't use workers and thus it'll be slower and may freeze thw window in browser's javascript. Please consider using prime() instead.

**`throws`** {RangeError}
bitLength MUST be > 0

#### Parameters:

| Name | Type | Default value | Description |
| :------ | :------ | :------ | :------ |
| `bitLength` | *number* | - | The required bit length for the generated prime |
| `iterations` | *number* | 16 | The number of iterations for the Miller-Rabin Probabilistic Primality Test |

**Returns:** *bigint*

A bigint probable prime of bitLength bits.

Defined in: [src/ts/prime.ts:100](https://github.com/juanelas/bigint-crypto-utils/blob/5bba6de/src/ts/prime.ts#L100)

___

### randBetween

▸ **randBetween**(`max`: *bigint*, `min?`: *bigint*): *bigint*

Returns a cryptographically secure random integer between [min,max]. Both numbers must be >=0

**`throws`** {RangeError}
Arguments MUST be: max > 0 && min >=0 && max > min

#### Parameters:

| Name | Type | Description |
| :------ | :------ | :------ |
| `max` | *bigint* | Returned value will be <= max |
| `min` | *bigint* | Returned value will be >= min |

**Returns:** *bigint*

A cryptographically secure random bigint between [min,max]

Defined in: [src/ts/randBetween.ts:15](https://github.com/juanelas/bigint-crypto-utils/blob/5bba6de/src/ts/randBetween.ts#L15)

___

### randBits

▸ **randBits**(`bitLength`: *number*, `forceLength?`: *boolean*): *Promise*<Uint8Array \| Buffer\>

Secure random bits for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()

**`throws`** {RangeError}
bitLength MUST be > 0

#### Parameters:

| Name | Type | Default value | Description |
| :------ | :------ | :------ | :------ |
| `bitLength` | *number* | - | The desired number of random bits |
| `forceLength` | *boolean* | false | If we want to force the output to have a specific bit length. It basically forces the msb to be 1 |

**Returns:** *Promise*<Uint8Array \| Buffer\>

A Promise that resolves to a UInt8Array/Buffer (Browser/Node.js) filled with cryptographically secure random bits

Defined in: [src/ts/randBits.ts:14](https://github.com/juanelas/bigint-crypto-utils/blob/5bba6de/src/ts/randBits.ts#L14)

___

### randBitsSync

▸ **randBitsSync**(`bitLength`: *number*, `forceLength?`: *boolean*): Uint8Array \| Buffer

Secure random bits for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()

**`throws`** {RangeError}
bitLength MUST be > 0

#### Parameters:

| Name | Type | Default value | Description |
| :------ | :------ | :------ | :------ |
| `bitLength` | *number* | - | The desired number of random bits |
| `forceLength` | *boolean* | false | If we want to force the output to have a specific bit length. It basically forces the msb to be 1 |

**Returns:** Uint8Array \| Buffer

A Uint8Array/Buffer (Browser/Node.js) filled with cryptographically secure random bits

Defined in: [src/ts/randBits.ts:45](https://github.com/juanelas/bigint-crypto-utils/blob/5bba6de/src/ts/randBits.ts#L45)

___

### randBytes

▸ **randBytes**(`byteLength`: *number*, `forceLength?`: *boolean*): *Promise*<Uint8Array \| Buffer\>

Secure random bytes for both node and browsers. Node version uses crypto.randomBytes() and browser one self.crypto.getRandomValues()

**`throws`** {RangeError}
byteLength MUST be > 0

#### Parameters:

| Name | Type | Default value | Description |
| :------ | :------ | :------ | :------ |
| `byteLength` | *number* | - | The desired number of random bytes |
| `forceLength` | *boolean* | false | If we want to force the output to have a bit length of 8*byteLength. It basically forces the msb to be 1 |

**Returns:** *Promise*<Uint8Array \| Buffer\>

A promise that resolves to a UInt8Array/Buffer (Browser/Node.js) filled with cryptographically secure random bytes

Defined in: [src/ts/randBytes.ts:12](https://github.com/juanelas/bigint-crypto-utils/blob/5bba6de/src/ts/randBytes.ts#L12)

___

### randBytesSync

▸ **randBytesSync**(`byteLength`: *number*, `forceLength?`: *boolean*): Uint8Array \| Buffer

Secure random bytes for both node and browsers. Node version uses crypto.randomFill() and browser one self.crypto.getRandomValues()

**`throws`** {RangeError}
byteLength MUST be > 0

#### Parameters:

| Name | Type | Default value | Description |
| :------ | :------ | :------ | :------ |
| `byteLength` | *number* | - | The desired number of random bytes |
| `forceLength` | *boolean* | false | If we want to force the output to have a bit length of 8*byteLength. It basically forces the msb to be 1 |

**Returns:** Uint8Array \| Buffer

A UInt8Array/Buffer (Browser/Node.js) filled with cryptographically secure random bytes

Defined in: [src/ts/randBytes.ts:46](https://github.com/juanelas/bigint-crypto-utils/blob/5bba6de/src/ts/randBytes.ts#L46)

___

### toZn

▸ **toZn**(`a`: *number* \| *bigint*, `n`: *number* \| *bigint*): *bigint*

Finds the smallest positive element that is congruent to a in modulo n

**`remarks`** 
a and b must be the same type, either number or bigint

**`throws`** {RangeError}
Excpeption thrown when n is not > 0

#### Parameters:

| Name | Type | Description |
| :------ | :------ | :------ |
| `a` | *number* \| *bigint* | An integer |
| `n` | *number* \| *bigint* | The modulo |

**Returns:** *bigint*

A bigint with the smallest positive representation of a modulo n

Defined in: node_modules/bigint-mod-arith/dist/esm/types/ts/toZn.d.ts:15