Message Digests#

Cryptographic hash functions (also known as message digest algorithms) convert data of arbitrary size to a fixed-size digest. These are most often used for generating checksums or identifiers for large data blobs.

Read more about Cryptographic hash functions on Wikipedia.

Hash#

Use the global convenience variables to create hashes using common algorithms.

import Crypto

let digest = try SHA1.hash("hello")
print(digest.hexEncodedString()) // aaf4c61ddcc5e8a2dabede0f3b482cd9aea9434d

See the Crypto module’s global variables for a list of all available hash algorithms.

Streaming#

You can create a Digest manually and use its instance methods to create a hash for one or more data chunks.

var sha256 = try Digest(algorithm: .sha256)
try sha256.reset()
try sha256.update(data: "hello")
try sha256.update(data: "world")
let digest = try sha256.finish()
print(digest) /// Data

BCrypt#

BCrypt is a popular hashing algorithm that has configurable complexity and handles salting automatically.

Hash#

Use the hash(_:cost:salt:) method to create BCrypt hashes.

let digest = try BCrypt.hash("vapor", cost: 4)
print(digest) /// data

Increasing the cost value will make hashing and verification take longer.

Verify#

Use the verify(_:created:) method to verify that a BCrypt hash was created by a given plaintext input.

let hash = try BCrypt.hash("vapor", cost: 4)
try BCrypt.verify("vapor", created: hash) // true
try BCrypt.verify("foo", created: hash) // false

HMAC#

HMAC is an algorithm for creating keyed hashes. HMAC will generate different hashes for the same input if different keys are used.

let digest = try HMAC.SHA1.authenticate("vapor", key: "secret") 
print(digest.hexEncodedString()) // digest

See the HMAC class for a list of all available hash algorithms.

Streaming#

HMAC hashes can also be streamed. The API is identical to hash streaming.