85 lines
2.7 KiB
JavaScript
85 lines
2.7 KiB
JavaScript
(function() {
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'use strict';
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function ProvisioningCipher() {}
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ProvisioningCipher.prototype = {
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decrypt: function(provisionEnvelope) {
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var masterEphemeral = provisionEnvelope.publicKey.toArrayBuffer();
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var message = provisionEnvelope.body.toArrayBuffer();
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if (new Uint8Array(message)[0] != 1) {
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throw new Error('Bad version number on ProvisioningMessage');
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}
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var iv = message.slice(1, 16 + 1);
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var mac = message.slice(message.byteLength - 32, message.byteLength);
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var ivAndCiphertext = message.slice(0, message.byteLength - 32);
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var ciphertext = message.slice(16 + 1, message.byteLength - 32);
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return libsignal.Curve.async
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.calculateAgreement(masterEphemeral, this.keyPair.privKey)
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.then(function(ecRes) {
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return libsignal.HKDF.deriveSecrets(
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ecRes,
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new ArrayBuffer(32),
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'TextSecure Provisioning Message'
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);
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})
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.then(function(keys) {
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return libsignal.crypto
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.verifyMAC(ivAndCiphertext, keys[1], mac, 32)
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.then(function() {
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return libsignal.crypto.decrypt(keys[0], ciphertext, iv);
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});
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})
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.then(function(plaintext) {
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var provisionMessage = textsecure.protobuf.ProvisionMessage.decode(
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plaintext
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);
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var privKey = provisionMessage.identityKeyPrivate.toArrayBuffer();
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return libsignal.Curve.async
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.createKeyPair(privKey)
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.then(function(keyPair) {
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var ret = {
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identityKeyPair: keyPair,
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number: provisionMessage.number,
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provisioningCode: provisionMessage.provisioningCode,
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userAgent: provisionMessage.userAgent,
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readReceipts: provisionMessage.readReceipts,
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};
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if (provisionMessage.profileKey) {
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ret.profileKey = provisionMessage.profileKey.toArrayBuffer();
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}
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return ret;
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});
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});
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},
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getPublicKey: function() {
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return Promise.resolve()
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.then(
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function() {
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if (!this.keyPair) {
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return libsignal.Curve.async.generateKeyPair().then(
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function(keyPair) {
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this.keyPair = keyPair;
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}.bind(this)
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);
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}
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}.bind(this)
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)
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.then(
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function() {
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return this.keyPair.pubKey;
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}.bind(this)
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);
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},
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};
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libsignal.ProvisioningCipher = function() {
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var cipher = new ProvisioningCipher();
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this.decrypt = cipher.decrypt.bind(cipher);
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this.getPublicKey = cipher.getPublicKey.bind(cipher);
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};
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})();
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