I'm working on a project that take the GPS location every 5 seconds and send it to the server, but i need to make a little of security, so i need to encrypt the location in android device and decrypt it in server side, so i'm searching for a simple algorithm to do this
Thanks in advance
The ideas for you to try:
Send your data over HTTPS. It will add the layer of security you need and it's one of the simplest methods available.
Use Java Encryption API with asymmetric cryptographic algorithm like RSA. You should probably avoid using AES or similar symmetric algorithm because you should not store passphrase in your Android app - it could be quite easily compromised.
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I'm working on IoT gateway which will collect data from IoT devices. IoT device is a constrained device which couldn't use HTTPS.
It sends periodically small amount of data - from sensors, with some aditional information as time, message id, unit id etc.
Right now we've got an implementation of gateway as REST API in Java open for everyone. So It accepts requests as JSON from any device, without ensuring that data comes from our device are not corupted or compromised.
Without having ability to secure data by HTTPS, what is the best way to design interface between gateway and device?
Without having ability to secure data by HTTPS, what is the best way to design interface between gateway and device?
You can still use a symmetric encryption/authentication to ensure integrity and confidentiality, which should be feasible even for low end devices
As an inspiration you may have a loot at JWE with a shared key.
You could limit replays using some timestamp/counter or having idempotent consumers.
Regardless that - missing tls/https ypu have to take care of a lot of things, such as how to protect a shared key, update if revoked, etc
If the device can't do https (with any set of cipher suites) you will probably have to make serious compromises and not have some aspects of a secure connection. A bit simplified, but https is pretty much the minimal full suite of how it can be done, there is nothing "unnecessary". You might not need everything, but it entirely depends on your usecase and threat model. Before implementing this, you should have a full understanding of exactly what https provides, and how, so you can use applicable parts. Also note that this is not at all straightforward to implement, a custom implementation will likely be vulnerable.
How constrained is your device really? There are small implementations of TLS that wouldn't require you to compromise on security such as wolfSSL.
Footprint sizes (compiled binary size) for wolfSSL range between 20-100kB depending on build options and the compiler being used.
Regarding runtime memory usage, wolfSSL will generally consume between 1-36 kB per SSL/TLS session.
Anyway, I would not recommend you try and implement your own cipher suite unless you REALLY know what you are doing.
Given the kind of tools you've mentioned having access to (HTTP/JSON), I suggest looking at JOSE, which is a standardized way of signing and encrypting this kind of data. Specifically you'll be interested in JWE, JWS, and JWT. The learning curve for JOSE is unfortunately somewhat steep and the docs are somewhat sparse, but it is quite effective and implemented on a variety of platforms, and will save you a lot of headache in inventing your own protocols (which is quite difficult to do correctly). I've had pretty good luck building custom systems around JOSE.
There are some key questions you need to ask:
Do you need mutual authentication, or only authentication of the device? If the device only writes and never reads, then you likely only need to authenticate the device and not the server.
Can you accept the risk of a single shared secret baked into the devices? The problem with a single shared secret is that if any device is reverse engineered, then all protection is lost until you phase out all devices with that key.
Can you accept the manufacturing cost of a per-device secret? Depending on your manufacturing process, generating a unique secret for each device may be difficult.
Can you accept the on-device storage space and processing requirements of a client certificate? If not, can you accept the logistics of maintaining a server-side database of every device's key? (If you can except neither, then you'll have to go with a single shared secret for the whole system.)
My gut feeling is you're talking about a device that can handle the complexity of a client cert, but not a full HTTPS stack. If you also can handle the complexity of generating a certificate during manufacturing, or your customers are willing to register their devices, then I recommend the following:
During manufacture or registration, generate a certificate and signing request. Send it to your server to be signed, and install the signed X.509 on the device. (Generating a CSR on the device is also an option, but many small devices lack the entropy to generate a decent random number. There are tradeoffs either way.)
Generate a certificate for the server, and install its public key on all devices.
Assuming the amount of data you're sending is small, I'd bundle it all into the JWT (web token), encrypted to the server's public key, and signed with the client's private key. Typically JWTs are used to exchange authentication information, but they're really just a standardized container for sending signed and encrypted JSON data, so they really can be anything you want.
In order to prevent replay attacks, the server needs to keep track of messages its seen before. There are two main approaches I like, depending on your situation:
Make the jti (JWT ID) a combination of the timestamp and a random value (in which case the server just needs to keep a cache of recent JTIs and reject too-old timestamps)
Make the jti a combination of the device id and a monotonically increasing message id. The server then needs to keep track of the last-seen message id for each device, and reject any ids less-than-or-equal to that.
If you don't need encryption, look at JWS instead, which just signs the data. None of these techniques require encryption, and it's a little simpler if you take that part out (you don't need a server certificate, for example). You can still prevent replays, and only allow trusted clients to connect. It is possible for someone to reverse engineer your device and pull out its client cert. The advantage of a client cert is that if you discover the abuse, you can then just ban that one cert. With a shared secret you can't do that.
The basic advantage of all of this is that JOSE is based on JSON, which is something you already understand and know how to parse and work with. But it's also reasonably compact for a string-based protocol. It's also extremely flexible in terms of algorithms, which makes it much easier to implement on smaller hardware. You could build all the same things by hand using public/private keys, but JOSE has already thought through many of the tricky security problems.
If only it were better documented....
I'm a young professional who's into embedded design, IT networking, control/monitoring systems and much more. Currently, I'm developing a monitoring system using a device from Tibbo Techonology, their DS1102.
http://tibbo.com/products/controllers/ds110x/ds1102
It's a programmable device that covers serial and ethernet communications. For my project, its main tasks are serial data collection and database population. Serial communication is done through RS485 and database used is MySQL 5.5. My database is hosted on a public IP which also runs a webserver for the interface while my device is behind a NAT. It connects to the database directly using the public IP.
I'd like to ask for advices so that I can enhance and upgrade it. Right now these are the
questions I'd like to ask.
Which is better? Having the server on a public IP or using port forwarding?
I'm also using it as webserver for the interface of my monitoring system.
To communicate with the device (rebooting, changing IP etc), I wrote an application in
python using UDP (using port 65535 of device) and also set the device to communicate with the application for specific commands. My concern is I want to encrypt the communication between my python app and the device both ways. The only available function for both encrypting and decrypting on the DS1102 is RC4. What are your thoughts on using RC4 for this application? Also, I'm planning to do port forwarding on port 65535 so that I can use my python app from the outside. Can RC4 be reliable for this too? I really want to learn how to use encryptions properly.
I'm also planning to implement SMTP for alert messages. Tibbo has a sample code from which I based mine. Problem is, it's on AUTH PLAIN LOGIN. I think I want to turn it to STARTTLS later. Can you recommend some lessons on the algorithm of STARTTLS?
What are those details on MAIL FROM:<> and RCPT TO:<>? Because on using the command
DATA, the programmer can write anyway From: and To: which can make his identity someone else.
That's it for now. Suggestions are very welcome.
You can also share some good reading materials and links. I'm always hungry for learning. :)
Thanks for your time.
2.
Encryption substitutes the confidentiality of an arbitrary amount of data (the plaintext) with the confidentiality of a small amount data (the key). In other words, your communication is only as confidential as the key – if the shared secret key leaks out, the encryption is worthless. More on this.
Also note that plain RC4 provides no authenticity (message integrity). An adversary can modify messages as much as he wants. He can even send his own messages which will be considered perfectly valid by the cipher. Verifying the validity of the messages is is up to the code that parses the messages.
If your messages are simple (only a few bytes or so), an adversary could simply send random bytes until they decrypt such that they form a valid message, without knowing anything about the key. This happens on average after only 100 attempts for a 1-byte message for example.
You will obviously have to use some sort of a nonce to prevent trivial replay attacks.
RC4 is also rather quirky per se. I guess you are already aware of the numerous "drop-n" variants and so on.
In short, protocol design is perilous. Even experts often get it wrong (look at WEP for example). The most straightforward way to solve this would be to find hardware that can handle an existing protocol such as TLS.
I am trying to use asymmetric encryption to encrypt firmware. The bootloader will decrypt and update the flash. This is on a embedded device with 32 bit CPU executing at 60MHz.
I want to use ECC due to its varies advantages. I am new to encryption and my understanding os ECC as implemented in ECIES is to use ECC for the key generation and use AES for actual data encryption. Due to code and ram size, I cannot support multiple encryption algorithms.
Is there a implementation of ECC that can be used just like AES. All I am looking for is to use a "Private key" to encrypt firmware and the bootloader uses "Public Key" to decrypt it.
Thanks.
I'm not sure that you completely understand what ECIES consists of:
http://en.wikipedia.org/wiki/Integrated_Encryption_Scheme
That's quite a bit of work, and it requires a whole lot of primitives, including at least one symmetric primitive, it seems to me. That might as well be AES.
Let's start from the last sentence of the question:
All I am looking for is to use a "Private key" to encrypt firmware and the bootloader uses "Public Key" to decrypt it.
There's some confusion in terminology here. Private keys are used to decrypt (or sign) and public keys are used to encrypt (or verify). If I understand correctly, what you want is for the bootloader to verify a signature on the firmware so that only a firmware that was properly signed by yourself will be accepted by the bootloader.
There are various asymmetric signature schemes which can be used for this purpose, including some which are based on eliptic curve cryptography. For example you could use the OpenSSL implementation of ECDSA (see http://www.openssl.org/docs/crypto/ecdsa.html).
I'm afraid there's not enough information in the question to properly choose the best signature scheme (and possibly an encryption scheme as well if there is a need to keep the firmware secret). In any case, good cryptography is not enough to make a system secure and other considerations such as secure implementation are no less important.
If this is is something that is important for you to protect and that you are worried that hackers may try to break, I would strongly advise procuring the services of a security professional. Using cryptography correctly is a very tricky business that requires a full understanding of the system - otherwise you may find yourself in a situation like this
If you look for "authentication" you have to use asymmetric algorithm like EC, this usually done because if the user or process want to update the "firmware" he should identify him self to the bootloader by his "signature" to check who request this update.
After that is done, the bootloader will load the symmetric key from a secure memory to decrypt what you want to do.
So, you have a symmetric key for encryption (AES), and asymmetric two keys for authentication (=Who are you?).
Note: there is no advantages of EC on 32 bit CPU executing at 60MHz for Encryption, unless your application need asymmetric for Encryption NOT authentication, this happen due to line between the user and bootloader is not secure.
Therefore, you could use bootloader's "public key" to encrypt firmware and the bootloader uses its "private Key" to decrypt it, however, the implementation cost a lot due to the high computing for asymmetric algorithm.
Look for "lightweight cryptography", it is typical for your application.
Instead of spending a bunch of $$ on ssl, can I implement RSA on my own? (I don't care about proving the site's identity; I just want to encrypt a password between clients and the server to protect from man-in-the-middle attacks). I've read that any custom solutions are likely to be very insecure, but could someone read my plan and give a thoughtful response?
First I would create public and private keys. I would encrypt the client password with javascript by translating the letters of the password to ascii-values, and then multiply or add (any suggestions?) these ascii-values to get the "unencrypted message". I would then encrypt this message using javascript and the public key.
On the server, I would decrypt the secure message using the private key and end up with the sum/product of the password's ascii-values. Any tips on how to get the individual letters from that?
Edit: I've reached the conclusion that SSL is the best way to go. I was only looking at the client to server side of the deal (where all the client sends is a password). Of course, the information sent by the server to the client is valuable, and should not be vulnerable to MITM attacks. Thanks for the free SSL suggestions.
Thanks
There are a bunch of reasons not to roll your own encryption.
SSL gives the user confidence that the site is secure and that eavesdroppers cannot view the password on the wire. If you don't use SSL then the usual browser indications that the site is secure will not be present.
It's really hard to get RSA right (or any crypto algorithm for that matter). First off, using raw RSA is insecure and you need to have an appropriate padding mechanism and wotnot to make it actually secure. RSA can also only encrypt n-1 bytes of data, where n is the size of the key.
Leave crypto to the cryptographers. The first issue with your proposed system is that you're missing the point of using a secure transport: You don't need to do any special encoding of your data (the conversion to ascii and multiplying/summing or whatever part) because the secure transport means that eavesdroppers cannot see what's going past.
Your proposal does not protect against man-in-the-middle attacks. It (kinda) prevents eavesdropping, which is a different problem.
That said, you certainly can implement RSA in Javascript with a bit of effort, but just be aware that it is unlikely to be secure until you've had a bunch of cryptanalysts look at it and try to break it. You will make a mistake somewhere along the line, even if you are the best programmer in the world.
The user experience will also suffer because it will be very hard for the user to verify that they are, in fact, talking to your server.
SSL is a well known, well analysed, not-yet-broken protocol that can be free if you use a self-signed certificate (another poor user experience, but at least it's still fairly secure). Think very carefully before you decide to cheap out on the crypto, and make sure you weigh the cost of a certificate against your development time (it'll take you many hours to implement RSA) and the potential cost of leaking important customer information (their password). The cost of the certificate is likely to be insignificant compared to the rest of the project cost.
You can use a self-signed certificate on the server and trust it explicitly on the client (i.e. encode certificate parameters etc). So you don't need to reinvent the wheel. I would say more - depending on the library you can use PSK (pre-shared key) cipher suites and get rid of certificates completely.
I'm not sure you need SSL if you cannot afford a certificate. Obviously, your data you intend to protect does not have much value.
The public/private key system is best way to go. By the time you figure out how to roll your own and get your CA certificate included in all the major browsers and Operating Systems and become your own Certificate authority, I think you will find spending a few 100$ on cert is cheap.
If you are looking for SSL but not spending money use www.startssl.com as that will allow you to use SSL free. Creating your own solution will take time and if not done the correct way will be insecure.
Yes, it is possible to implement plain RSA "by hand" in this way. To create the unencrypted message, you can simply use the bits of the message. For example, if your password is cheese:
c h e e s e
0x63 0x68 0x65 0x65 0x73 0x65
The number to encrypt could then be simply 0x636865657365. You'll need to use math routines that can handle large integers (native Javascript numbers aren't big enough).
Standard warnings apply, your solution will have a fatal flaw in some way, etc etc.
I don't care about proving the site's identity; I just want to encrypt a password between clients and the server to protect from man-in-the-middle attacks)
That's exactly why you do care about proving the site's identity.
That in turn is why just using RSA without an authentication scheme isn't secure. It's no good having a secret conversation when you can't identify who you're talking to.
I'm connecting mi cell phone application in J2ME to a web service and I have to send a SHA256 hash to it in order to validate some data received. I also need to be capable to store some information encrypted into the cell phone. I was thinking to use AES (rinjdael) symmetric encryption.
Anyone knows about any code example using AES encryption in J2ME ?
I would advise looking into the open source bouncycastle library.
It has been successfully used for cryptography on J2ME.