SecretBox class

From: PyNaCl's readthedocs

Secret Key Encryption

Secret key encryption (also called symmetric key encryption) is analogous to a safe. You can store something secret through it and anyone who has the key can open it and view the contents. SecretBox functions as just such a safe, and like any good safe any attempts to tamper with the contents are easily detected.

Secret key encryption allows you to store or transmit data over insecure channels without leaking the contents of that message, nor anything about it other than the length.

Secretbox uses XSalsa20 and Poly1305 to encrypt and authenticate messages with secret-key cryptography. The length of messages is not hidden.

It is the caller's responsibility to ensure the uniqueness of nonces—for example, by using nonce 1 for the first message, nonce 2 for the second message, etc. Nonces are long enough that randomly generated nonces have negligible risk of collision.

Messages should be small because:

  1. The whole message needs to be held in memory to be processed.
  2. Using large messages pressures implementations on small machines to decrypt and process plaintext before authenticating it. This is very dangerous, and this API does not allow it, but a protocol that uses excessive message sizes might present some implementations with no other choice.
  3. Fixed overheads will be sufficiently amortised by messages as small as 8KB.
  4. Performance may be improved by working with messages that fit into data caches. Thus large amounts of data should be chunked so that each message is small. (Each message still needs a unique nonce.) If in doubt, 16KB is a reasonable chunk size.
Inheritance
Available Extensions

Constructors

SecretBox(Uint8List secret)
SecretBox.decode(String data, [Encoder defaultDecoder = decoder])
factory

Properties

doDecrypt ↔ Crypting
getter/setter pairoverride
doEncrypt ↔ Crypting
getter/setter pairoverride
encoder → Encoder
no setteroverride
first ↔ int
The first element.
getter/setter pairinherited
hashCode → int
The hash code for this object.
no setterinherited
isEmpty → bool
Whether this collection has no elements.
no setterinherited
isNotEmpty → bool
Whether this collection has at least one element.
no setterinherited
iterator → Iterator<int>
A new Iterator that allows iterating the elements of this Iterable.
no setterinherited
key → ByteList
no setteroverride
last ↔ int
The last element.
getter/setter pairinherited
length ↔ int
The number of objects in this list.
getter/setter pairinherited
reversed → Iterable<int>
An Iterable of the objects in this list in reverse order.
no setterinherited
runtimeType → Type
A representation of the runtime type of the object.
no setterinherited
single → int
Checks that this iterable has only one element, and returns that element.
no setterinherited

Methods

add(int element) → void
Adds value to the end of this list, extending the length by one.
inherited
addAll(Iterable<int> iterable) → void
Appends all objects of iterable to the end of this list.
inherited
any(bool test(int element)) → bool
Checks whether any element of this iterable satisfies test.
inherited
asMap() → Map<int, int>
An unmodifiable Map view of this list.
inherited
cast<R>() → List<R>
Returns a view of this list as a list of R instances.
inherited
clear() → void
Removes all objects from this list; the length of the list becomes zero.
inherited
contains(Object? element) → bool
Whether the collection contains an element equal to element.
inherited
decrypt(ByteList encryptedMessage, {Uint8List? nonce}) → Uint8List
inherited
elementAt(int index) → int
Returns the indexth element.
inherited
encode([Encoder? encoder]) → String
inherited
encrypt(Uint8List plainText, {Uint8List? nonce}) → EncryptedMessage
inherited
every(bool test(int element)) → bool
Checks whether every element of this iterable satisfies test.
inherited
expand<T>(Iterable<T> f(int element)) → Iterable<T>
Expands each element of this Iterable into zero or more elements.
inherited
fillRange(int start, int end, [int? fill]) → void
Overwrites a range of elements with fillValue.
inherited
firstWhere(bool test(int element), {int orElse()?}) → int
The first element that satisfies the given predicate test.
inherited
fold<T>(T initialValue, T combine(T previousValue, int element)) → T
Reduces a collection to a single value by iteratively combining each element of the collection with an existing value
inherited
followedBy(Iterable<int> other) → Iterable<int>
Creates the lazy concatenation of this iterable and other.
inherited
forEach(void action(int element)) → void
Invokes action on each element of this iterable in iteration order.
inherited
getRange(int start, int end) → Iterable<int>
Creates an Iterable that iterates over a range of elements.
inherited
indexOf(Object? element, [int start = 0]) → int
The first index of element in this list.
inherited
indexWhere(bool test(int element), [int start = 0]) → int
The first index in the list that satisfies the provided test.
inherited
insert(int index, int element) → void
Inserts element at position index in this list.
inherited
insertAll(int index, Iterable<int> iterable) → void
Inserts all objects of iterable at position index in this list.
inherited
join([String separator = ""]) → String
Converts each element to a String and concatenates the strings.
inherited
lastIndexOf(Object? element, [int? start]) → int
The last index of element in this list.
inherited
lastIndexWhere(bool test(int element), [int? start]) → int
The last index in the list that satisfies the provided test.
inherited
lastWhere(bool test(int element), {int orElse()?}) → int
The last element that satisfies the given predicate test.
inherited
map<T>(T f(int element)) → Iterable<T>
The current elements of this iterable modified by toElement.
inherited
noSuchMethod(Invocation invocation) → dynamic
Invoked when a nonexistent method or property is accessed.
inherited
reduce(int combine(int previousValue, int element)) → int
Reduces a collection to a single value by iteratively combining elements of the collection using the provided function.
inherited
remove(Object? element) → bool
Removes the first occurrence of value from this list.
inherited
removeAt(int index) → int
Removes the object at position index from this list.
inherited
removeLast() → int
Removes and returns the last object in this list.
inherited
removeRange(int start, int end) → void
Removes a range of elements from the list.
inherited
removeWhere(bool test(int element)) → void
Removes all objects from this list that satisfy test.
inherited
replaceRange(int start, int end, Iterable<int> newContents) → void
Replaces a range of elements with the elements of replacements.
inherited
retainWhere(bool test(int element)) → void
Removes all objects from this list that fail to satisfy test.
inherited
setAll(int index, Iterable<int> iterable) → void
Overwrites elements with the objects of iterable.
inherited
setRange(int start, int end, Iterable<int> iterable, [int skipCount = 0]) → void
Writes some elements of iterable into a range of this list.
inherited
shuffle([Random? random]) → void
Shuffles the elements of this list randomly.
inherited
singleWhere(bool test(int element), {int orElse()?}) → int
The single element that satisfies test.
inherited
skip(int count) → Iterable<int>
Creates an Iterable that provides all but the first count elements.
inherited
skipWhile(bool test(int element)) → Iterable<int>
Creates an Iterable that skips leading elements while test is satisfied.
inherited
sort([int compare(int a, int b)?]) → void
Sorts this list according to the order specified by the compare function.
inherited
sublist(int start, [int? end]) → ByteList
Returns a new list containing the elements between start and end.
inherited
take(int count) → Iterable<int>
Creates a lazy iterable of the count first elements of this iterable.
inherited
takeWhile(bool test(int element)) → Iterable<int>
Creates a lazy iterable of the leading elements satisfying test.
inherited
toList({bool growable = true}) → List<int>
Creates a List containing the elements of this Iterable.
inherited
toSet() → Set<int>
Creates a Set containing the same elements as this iterable.
inherited
toString() → String
A string representation of this object.
inherited
where(bool test(int element)) → Iterable<int>
Creates a new lazy Iterable with all elements that satisfy the predicate test.
inherited
whereType<T>() → Iterable<T>
Creates a new lazy Iterable with all elements that have type T.
inherited

Operators

operator +(List<int> other) → List<int>
Returns the concatenation of this list and other.
inherited
operator ==(Object other) → bool
The equality operator.
inherited
operator [](int index) → int
The object at the given index in the list.
inherited
operator []=(int index, int value) → void
Sets the value at the given index in the list to value.
inherited

Constants

decoder → const Base16Encoder
keyLength → const int
macBytes → const int