ServerCrypto is a library that makes server-side cryptography easy in Swift.
To use ServerCrypto in your project, add this line to your Package.swift:
.package(url: "https://github.com/alexaubry/ServerCrypto", from: "1.0.0")Make sure you have OpenSSL installed before using the library.
On macOS, you need to provide the following flags to build or test from the command line:
swift build -Xswiftc -I/usr/local/opt/openssl/include -Xlinker -L/usr/local/opt/openssl/libTo compute the hash of a sequence of bytes, you use an instance of Hasher.
Hasher can generate hashes for Data, [UInt8] ; and any type than conforms to the Bytes protocols.
The following hashing algorithms are supported:
.md4 .md5 .sha1 .sha224 .sha256 .sha384 .sha512 .ripeMd160
To compute the SHA-256 hash of a String, write the following code:
import Hash
let hasher = Hasher.sha256
let messageData = "Hello world".data(using: .utf8)!
let hashData = try hasher.makeHash(for: messageData) // Returns a Data object
let hashHexString = hashData.hexStringTo create an HMAC signature, you need:
- A message digest / hashing algorithm
- A key with a password
- A message to sign
You use an instance of Signer to generate an HMAC signature. Any type supported by Hasher is also supported by Signer.
To compute the SHA-256 HMAC of a String, you need to follow these steps:
1- Create an HMAC key with a password
import Signature
let key = try HMACKey(password: "secret")2- Create an HMAC signer
let signer = Signer.hmac(key)3- Get the HMAC for the message
let messageData = "Hello world".data(using: .utf8)!
let hmacData = signer.sign(messageData, with: .sha256) // Returns a Data object
let hmacHexString = hmacData.hexStringTo verify that an HMAC signature is valid for the message you expect, you need:
- A message digest / hashing algorithm
- A key with an expected password
- An expected message
- A signature to verify
You use an instance of Signer to verify an HMAC signature. The signature must be a Data object. The expected message can be any type supported by Hasher.
To verify the SHA-256 HMAC of a String, you need to follow these steps:
1- Create an HMAC key with the expected password
import Signature
let key = try HMACKey(password: "secret")2- Create an HMAC signer
let signer = Signer.hmac(key)3- Verify the HMAC for the message
let hmacData = ...
let messageData = "Hello world".data(using: .utf8)!
let isValid = signer.verify(signature: hmacData, for: messageData, with: .sha256) // Returns a BoolSignature.framework can generate signatures using private keys and algorithms like RSA and ECDSA.
To create a signature, you need:
- A message digest / hashing algorithm
- A private PEM-encoded key
- A message to sign
You use an instance of Signer to generate a signature. Any type supported by Hasher is also supported by Signer.
To compute the SHA-256 ECDSA signature of a String, you need to follow these steps:
1- Load a private key from a PEM file:
import Signature
let privateKey = try AsymmetricKey.makePrivateKey(readingPEMAtPath: "path/to/public/key.pem", passphrase: "...")You can also load a PEM key from memory using AsymmetricKey.makePrivateKey(readingPEMData: Data,passphrase: String?).
2- Create an asymmetric signer
let signer = Signer.asymmetric(privateKey)3- Get the signature for the message
let messageData = "Hello world".data(using: .utf8)!
let hmacData = signer.sign(messageData, with: .sha256) // Returns a Data object
let hmacHexString = hmacData.hexStringTo verify that a signature is valid for the message you expect, you need:
- A message digest / hashing algorithm
- The public key associated with the expected private key
- An expected message
- A signature to verify
You use an instance of Signer to verify a signature. The signature must be a Data object. The expected message can be any type supported by Hasher.
To verify that a SHA-256 ECDSA signature of a String is valid for the public key, you need to follow these steps:
1- Load the public key from a PEM file
import Signature
let publicKey = try AsymmetricKey.makePublicKey(readingPEMAtPath: "path/to/private/key.pem")You can also load the key from memory using AsymmetricKey.makePublicKey(readingPEMData: Data).
2- Create an asymmetric signer
let signer = Signer.asymmetric(publicKey)3- Verify the signatrure for the message
let hmacData = ...
let messageData = "Hello world".data(using: .utf8)!
let isValid = signer.verify(signature: hmacData, for: messageData, with: .sha256) // Returns a BoolAlexis Aubry, me@alexaubry.fr
You can find me on Twitter : @_alexaubry
ServerCrypto is available under the MIT License. See the LICENSE file for more info.