react-native-pvt-rsa-native

A native implementation of RSA key generation and encryption/decryption, sign/verify. Keychain implementation Implementation is in PKCS1

Support

iOS 10+ android 4.1+ (API 16)

Status

Features: Generation, Encryption, Decryption, Sign, Verify, Keychain support

Getting started

$ yarn add react-native-pvt-rsa-native

or:

$ npm install react-native-pvt-rsa-native --save

Older React-Native versions

If you are using an older version of React Native and are having issues try using v1.1.14

Example Usage

These basic examples show a typical use case using both promise chains and async/await. See the full API documentation below for more detail on the methods available.

Encrypt a message

Encrypt a message and subsequently decrypt it, using the RSA class in a promise chain structure.

import { RSA } from 'react-native-rsa-native';

let message = "my secret message";

RSA.generateKeys(4096) // set key size
.then(keys => {
    console.log('4096 private:', keys.private); // the private key
    console.log('4096 public:', keys.public); // the public key
    RSA.encrypt(message, keys.public)
    .then(encodedMessage => {
        console.log(`the encoded message is ${encodedMessage}`);
        RSA.decrypt(encodedMessage, keys.private)
        .then(decryptedMessage => {
            console.log(`The original message was ${decryptedMessage}`);
        });
    });
});

Sign a message

Sign a message and subsequently verify it, using the RSAKeychain class in an async/await structure.

import { RSAKeychain } from 'react-native-rsa-native';

async main() {
    let keyTag = 'com.domain.mykey';
    let message = "message to be verified";

    let publicKey = await generateKeyPair(keyTag);
    // Share the generated public key with third parties as desired.

    let messageSignature = await RSAKeychain.sign(message, keyTag);

    if (await RSAKeychain.verify(messageSignature, message, keyTag)) {
        // The signature matches: trust this message.
    } else {
        // The signature does not match.
    }

    await RSAKeychain.deletePrivateKey(keyTag);
}

async generateKeyPair(keyTag : string) {
    let keys = await RSAKeychain.generate(keyTag);
    return keys.public;
}

Check out example App.js for a full example

Documentation

RSA Class

A class that performs RSA cryptographic primitives in a simple and straightforward manner. If you would prefer to use the underlying operating system's built-in security keychain, use the RSAKeychain Class instead.

generateKeys

static generateKeys(keySize : number) : Promise<KeyPair>

Generate a public/private key pair of the given key size.

generate

static generate() : Promise<KeyPair>

Equivalent to generateKeys(2048)

encrypt

static encrypt(message : string, publicKey : string) : Promise<string>

Encrypt a given message with the provided public key, so it is decryptable with the matching private key.

decrypt

static decrypt(encodedMessage : string, privateKey : string) : Promise<string>

Decrypt a given encrypted message using the private key.

sign

static sign(message: string, privateKey : string) : Promise<string>

Sign a given message with the private key, so that any user with the message, the returned signature, and the matching public key can verify it was signed under this key.

verify

static verify(signature : string, message : string, publicKey : string) : Promise<boolean>

Verify whether or not a provided signature was produced by signing the given message with the private key paired to the provided public key.

RSAKeychain Class

Support: android 4.3+ (API 18)

Like the RSA Class, but when its methods are called, instead of directly accessing the private key, the private key is stored in the underlying operating system's keychain (see documentation for iOS and for Android) using a tag which the app can use to access it. Methods then take this tag instead of the private key.

generateKeys

static generateKeys(keyTag : string, keySize : number) : Promise<PublicKey>

Generate a public/private key pair of the given key size, and store the private key in the operating system keychain.

generate

static generate(keyTag : string) : Promise<KeyPair>

Equivalent to generateKeys(keyTag, 2048)

encrypt

static encrypt(message : string, keyTag : string) : Promise<string>

Retrieve the public key associated with the key tag, and encrypt a given message with that key, so it is decryptable with the matching private key.

decrypt

static decrypt(encodedMessage : string, keyTag : string) : Promise<string>

Decrypt a given encrypted message using the private key associated with the given key tag.

sign

static sign(message: string, keyTag : string) : Promise<string>

Sign a given message with the private key associated with the given key tag, so that any user with the message, the returned signature, and the matching public key can verify it was signed under this key.

signWithAlgorithm

static sign(message: string, keyTag : string, algorithm?: 'SHA256withRSA' | 'SHA512withRSA') : Promise<string>

Sign a given message with the private key associated with the given key tag, so that any user with the message, the returned signature, and the matching public key can verify it was signed under this key. The user can use SHA256withRSA or SHA512withRSA algorithm for signing. SHA256withRSA algorithm is not backward compatible on android and the user needs to generate new keypair for this to work. (available from ^1.1.0). The default is SHA512withRSA and if one wishes to use SHA512withRSA for signing without new keypair, then use the above sign method.

verify

static verify(signature : string, message : string, keyTag : string) : Promise<boolean>

Verify whether or not a provided signature was produced by signing the given message with private key associated with the given key tag.

verifyWithAlgorithm

static verify(signature : string, message : string, keyTag : string, algorithm?: 'SHA256withRSA' | 'SHA512withRSA') : Promise<boolean>

Verify whether or not a provided signature was produced by signing the given message with private key associated with the given key tag.

deletePrivateKey

static deletePrivateKey(keyTag : string) : Promise<boolean>

Delete the private key from the operating system's keychain. Returns true if the key was removed successfully.

KeyPair Type

Note: The KeyPair type does not strictly exist. Documentation provided here for convenience of understanding the return types of other methods.

Property | Description --|-- private : string | The RSA private key. public : string | The RSA public key.

PublicKey Type

Note: The PublicKey type does not strictly exist. Documentation provided here for convenience of understanding the return types of other methods.

Property | Description --|-- public : string | The RSA public key.

Credit

• Originally based on https://github.com/SamSaffron/react-native-key-pair
• iOS implementation reference

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