Randomization Services Reference

Inherits From

Not Applicable

Conforms To

Not Applicable

Import Statement

Objective-C

@import Security;

Swift

import Security

Availability

Not Applicable

Randomization Services is an API that generates cryptographically secure random numbers.

Functions

Obtaining a Random Number


    
      
           SecRandomCopyBytes(_:_:_:)
      
      
           SecRandomCopyBytes

Generates an array of cryptographically secure random bytes.

Declaration

Swift

func SecRandomCopyBytes(_ rnd: SecRandomRef, _ count: Int, _ bytes: UnsafeMutablePointer<UInt8>) -> Int32

Objective-C

int SecRandomCopyBytes ( SecRandomRef rnd, size_t count, uint8_t *bytes );

Parameters

`rnd`	The random number generator object to use. Specify `kSecRandomDefault` to use the default random number generator.
`count`	The number of random bytes to return in the array pointed to by the `bytes` parameter.
`bytes`	The random bytes generated by the function.

Return Value

Returns 0 if the function completed successfully and -1 if there was an error. Check the errno system variable for the error.

Discussion

This function reads from /dev/random to obtain an array of cryptographically-secure random bytes. For more information on the /dev/random random-number generator, see the manual page for random(4).

Availability

Available in iOS 2.0 and later.

Data Types

SecRandomRef SecRandomRef

Abstract Core Foundation-type object containing information about a random number generator.

Declaration

Swift

typealias SecRandomRef = COpaquePointer

Objective-C

typedef const struct __SecRandom * SecRandomRef;

Import Statement

Objective-C

@import Security;

Swift

import Security

Availability

Available in iOS 2.0 and later.

Constants

Number Generator Default
Indicates the default random number generator.

Declaration

Swift

let kSecRandomDefault: SecRandomRef

Objective-C

const SecRandomRef kSecRandomDefault;

Constants
- kSecRandomDefault
  
  kSecRandomDefault
  
  When passed to the SecRandomCopyBytes function as the random number generator reference, this constant indicates that the default number generator should be used.
  
  This constant is a synonym for NULL.
  
  Available in iOS 2.0 and later.