Language: JavaScript
Label: safe
CWE: CWE-331 \u2014 Insufficient Entropy
The product uses an algorithm or scheme that produces insufficient entropy, leaving patterns or clusters of values that are more likely to occur than others.

Code:
    CryptoModule.prototype.encrypt = function (data) {
        var encrypted = this.defaultCryptor.encrypt(data);
        if (!encrypted.metadata)
            return encrypted.data;
        var header = CryptorHeader.from(this.defaultCryptor.identifier, encrypted.metadata);
        var headerData = new Uint8Array(header.length);
        var pos = 0;
        headerData.set(header.data, pos);
        pos = header.length - encrypted.metadata.length;
        headerData.set(encrypted.metadata, pos);
        return Buffer.concat([headerData, Buffer.from(encrypted.data)]);
    };