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Cleanup gcm.js

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This commit is contained in:
Tankred Hase 2016-03-23 13:54:02 +08:00
parent a225027a6b
commit e5e76d2eb7
1 changed files with 46 additions and 23 deletions
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69
src/crypto/gcm.js
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@ -46,24 +46,17 @@ export function encrypt(cipher, plaintext, key, iv) {
return Promise.reject(new Error('GCM mode supports only AES cipher'));
}
const keySize = key.length * 8;
if (webCrypto && config.useNative && keySize !== 192) { // WebCrypto (no 192 bit support) see: https://www.chromium.org/blink/webcrypto#TOC-AES-support
return webCrypto.importKey('raw', key, { name: ALGO }, false, ['encrypt'])
.then(keyObj => webCrypto.encrypt({ name: ALGO, iv }, keyObj, plaintext))
.then(ciphertext => new Uint8Array(ciphertext));
if (webCrypto && config.useNative && key.length !== 24) { // WebCrypto (no 192 bit support) see: https://www.chromium.org/blink/webcrypto#TOC-AES-support
return webEncrypt(plaintext, key, iv);
} else if (nodeCrypto && config.useNative) { // Node crypto library
const en = new nodeCrypto.createCipheriv('aes-' + keySize + '-gcm', new Buffer(key.buffer), new Buffer(iv.buffer));
const encrypted = Buffer.concat([en.update(new Buffer(plaintext.buffer)), en.final()]);
return Promise.resolve(new Uint8Array(Buffer.concat([encrypted, en.getAuthTag()])));
return nodeEncrypt(plaintext, key, iv) ;
} else { // asm.js fallback
return Promise.resolve(asmCrypto.AES_GCM.encrypt(plaintext, key, iv));
}
}
/**
* Decrypt ciphertext input
* Decrypt ciphertext input.
* @param {String} cipher The symmetric cipher algorithm to use e.g. 'aes128'
* @param {Uint8Array} ciphertext The ciphertext input to be decrypted
* @param {Uint8Array} key The encryption key
@ -75,20 +68,50 @@ export function decrypt(cipher, ciphertext, key, iv) {
return Promise.reject(new Error('GCM mode supports only AES cipher'));
}
const keySize = key.length * 8;
if (webCrypto && config.useNative && keySize !== 192) { // WebCrypto (no 192 bit support) see: https://www.chromium.org/blink/webcrypto#TOC-AES-support
return webCrypto.importKey('raw', key, { name: ALGO }, false, ['decrypt'])
.then(keyObj => webCrypto.decrypt({ name: ALGO, iv }, keyObj, ciphertext))
.then(plaintext => new Uint8Array(plaintext));
if (webCrypto && config.useNative && key.length !== 24) { // WebCrypto (no 192 bit support) see: https://www.chromium.org/blink/webcrypto#TOC-AES-support
return webDecrypt(ciphertext, key, iv);
} else if (nodeCrypto && config.useNative) { // Node crypto library
const ctBuf = new Buffer(ciphertext.buffer);
const de = new nodeCrypto.createDecipheriv('aes-' + keySize + '-gcm', new Buffer(key.buffer), new Buffer(iv.buffer));
de.setAuthTag(ctBuf.slice(ctBuf.length - TAG_LEN, ctBuf.length));
const encrypted = ctBuf.slice(0, ctBuf.length - TAG_LEN);
return Promise.resolve(new Uint8Array(Buffer.concat([de.update(encrypted), de.final()])));
return nodeDecrypt(ciphertext, key, iv);
} else { // asm.js fallback
return Promise.resolve(asmCrypto.AES_GCM.decrypt(ciphertext, key, iv));
}
}
//////////////////////////
// //
// Helper functions //
// //
//////////////////////////
function webEncrypt(pt, key, iv) {
return webCrypto.importKey('raw', key, { name: ALGO }, false, ['encrypt'])
.then(keyObj => webCrypto.encrypt({ name: ALGO, iv }, keyObj, pt))
.then(ct => new Uint8Array(ct));
}
function webDecrypt(ct, key, iv) {
return webCrypto.importKey('raw', key, { name: ALGO }, false, ['decrypt'])
.then(keyObj => webCrypto.decrypt({ name: ALGO, iv }, keyObj, ct))
.then(pt => new Uint8Array(pt));
}
function nodeEncrypt(pt, key, iv) {
pt = new Buffer(pt.buffer);
key = new Buffer(key.buffer);
iv = new Buffer(iv.buffer);
const en = new nodeCrypto.createCipheriv('aes-' + (key.length * 8) + '-gcm', key, iv);
const ct = Buffer.concat([en.update(pt), en.final(), en.getAuthTag()]); // append auth tag to ciphertext
return Promise.resolve(new Uint8Array(ct));
}
function nodeDecrypt(ct, key, iv) {
ct = new Buffer(ct.buffer);
key = new Buffer(key.buffer);
iv = new Buffer(iv.buffer);
const de = new nodeCrypto.createDecipheriv('aes-' + (key.length * 8) + '-gcm', key, iv);
de.setAuthTag(ct.slice(ct.length - TAG_LEN, ct.length)); // read auth tag at end of ciphertext
const pt = Buffer.concat([de.update(ct.slice(0, ct.length - TAG_LEN)), de.final()]);
return Promise.resolve(new Uint8Array(pt));
}