SodiumObjc

Objective-C bindings for NaCL.

License

MIT License. See LICENSE for more information.

Usage

Public-Key Cryptography

Both NSString and NSData have been augmented with public-key encryption/decryption methods via the NSString+Nacl and NSData+NACL categories.

Encryption

NSString *plainText = @"I am about to get encrypted.";
NACLAsymmetricKeyPair *sendersKeyPair = [NACLAsymmetricKeyPair keyPair];
NACLAsymmetricKeyPair *receiversKeyPair = [NACLAsymmetricKeyPair keyPair];
NACLNonce *nonce = [NACLNonce nonce];

NSData *encryptedData;
encryptedData = [plainText encryptedDataUsingPublicKey:sendersKeyPair.publicKey
                                            privateKey:receiversKeyPair.privateKey
                                                 nonce:nonce];

Decryption

plainText = [encryptedData decryptedTextUsingPublicKey:receiversKeyPair.publicKey
                                            privateKey:sendersKeyPair.privateKey];

Compatibility

The methods that perform public-key encryption pack the nonce data at the beginning of the encrypted data object. The methods that perform public-key decryption without an explicit nonce argument expect nonce data to be packed at the beginning of the receiver. The methods that perform public-key decryption with an explicit nonce argument expect nonce data to not be packed at the beginning of the receiver. This behavior is provided as a convenience so you don't have to maintain the nonce. Keep in mind that if you consume encrypted data on another platform (or any library other than SodiumObjc), you should remove the nonce.

NSData *encryptedData;
encryptedData = [[plainText encryptedDataUsingPublicKey:sendersKeyPair.publicKey
                                             privateKey:receiversKeyPair.privateKey
                                                  nonce:nonce] dataWithoutNonce];

NSMutableURLRequest *request = ...
request.HTTPBody = encryptedData;

Private-Key Cryptography

Both NSString and NSData have been augmented with secret-key encryption/decryption methods via the NSString+Nacl and NSData+NACL categories, as well.

Encryption

NSString *plainText = @"I am about to get encrypted.";
NACLSymmetricPrivateKey *privateKey = [NACLSymmetricPrivateKey privateKey];
NACLNonce *nonce = [NACLNonce nonce];

NSData *encryptedData;
encryptedData = [plainText encryptedDataUsingPrivateKey:privateKey nonce:nonce];

Decryption

plainText = [encryptedData decryptedDataUsingPrivateKey:privateKey nonce:&nonce];

Compatibility

The methods that perform private-key encryption also pack the nonce data at the beginning of the encrypted data object. The methods that perform private-key decryption without an explicit nonce argument expect nonce data to be packed at the beginning of the receiver. The methods that perform private-key decryption with an explicit nonce argument expect nonce data to not be packed at the beginning of the receiver. This behavior is provided as a convenience so you don't have to maintain the nonce. Keep in mind that if you consume encrypted data on another platform (or any library other than SodiumObjc), you should remove the nonce.

NSData *encryptedData;
encryptedData = [[plainText encryptedDataUsingPrivateKey:privateKey
                                                   nonce:nonce] dataWithoutNonce];

NSMutableURLRequest *request = ...
request.HTTPBody = encryptedData;

Signatures

Both NSString and NSData have been augmented with signing methods via the NSString+Nacl and NSData+NACL categories.

Signing

NSString *plainText = @"I am about to get encrypted.";
NACLSigningKeyPair *signingKeyPair = [NACLSigningKeyPair keyPair];
NACLNonce *nonce = [NACLNonce nonce];

NSData *signedData;
signedData = [plainText signedDataUsingPrivateKey:signingKeyPair.privateKey];

Verifying

NSString *verifiedText;
verifiedText = [signedData verifiedTextUsingPublicKey:signingKeyPair.publicKeyPair];

Building

Building libsodium consists of the following steps:

• Fetch the contents of the libsodium submodule
• Building libsodium for all involved architectures
• Copying the built archives and headers to the correct location

The steps that I use to do this are:

git submodule update --init --recursive
cd libsodium-darwin-build
make clean all
cp libsodium-ios.a ../lib/ios/
cp libsodium-osx.a ../lib/osx/
cp -R build/iPhoneOS-arm64/include ../lib/ios/
cp -R build/MacOSX-x86_64/include ../lib/osx/