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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.

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