I'm watching a football game # https://watch.foxtel.com.au/ and I saw in the inspector the site loads the file:
https://watch.foxtel.com.au/app/static/js/npm.crypto-js.7f96017841bd7fff1e02.chunk.js
I think this relates to https://www.npmjs.com/package/crypto-js
Does that NPM package relate to cryptocurrency or cryptography?
Help appreciated.
crypto.js is purely a cryptography library, without a focus on cryptocurrency specifically.
Looking at the docs, indeed crypto.js does support ECDSA over secp256k1, and SHA256, the primary cryptographic primitives used in most Bitcoin derived cryptocurrencies.
I guess technically you could leverage its hashing functions to mine, and its ECDSA signature functions to create BTC transactions, but it certainly wouldn't be a library I would use writing an attack like that, there are many other libraries much better suited.
If you used crypto.js for cryptocurrency related work, one would have to build out all of the cryptocurrency specific stuff from first principles, (e.g. conversion of elliptic curve points (after scalar multiplication) to valid public keys, and on to base58 encoded Bitcoin addresses, etc).
It's much more likely it was used to leverage a cryptographic primitive for authentication or equivalent.
Update:
This actually just looks like the crypto module from Node, thus definitely not cryptocurrency related.
Related
This is the article published by Microsoft for encrypting/decrypting data using RSA:
https://learn.microsoft.com/en-us/dotnet/standard/security/walkthrough-creating-a-cryptographic-application
As a relatively new person into the cryptography world and having read a comment on stackoverflow saying that cryptography should use a hybrid model, I researched that and it seems that hybrid models use AES and RSA for encryption and I was wondering if the example provided by Microsoft fits into the hybrid model since it uses both and if is constructed well enough and not just for novice devs just venturing into the world of cryptography.
I already have a working example where an app would encode and another would decode by loading the private key file, similar to the example.
I found an article here:
https://www.codeproject.com/Tips/834977/Using-RSA-and-AES-for-File-Encryption
He creates signatures and manifests and I'm wondering if this is what I'm looking for is Microsoft's example generally just enough, or weak?
PS: I removed the key container code and persistence as I don't want to persist or store my keys on the local machine, instead they are exported as standalone files to be stored in a DB maybe, so I'm not looking for opinions on that part at the moment.
and not just for novice devs just venturing into the world of cryptography
Well, at least it tries to define some kind of protocol, although very sparse. It also uses CBC mode (implicitly, never a good idea) and RSA with PKCS#1 v1.5 padding for encryption. Most people would opt for OAEP if RSA is used and use an authenticated cipher such as GCM.
I already have a working example where an app would encode and another would decode by loading the private key file, similar to the example.
Bad idea, the example is for file encryption, not for transport mode security, for which you need a secure transport protocol. Both the RSA implementation and CBC implementation are malleable, and are both susceptible to padding oracle attacks as well.
I don't want to persist or store my keys on the local machine
You need to establish trust, something that is missing from the example. And to establish trust you do need to persist your keys, especially if they have been randomly generated.
In the end, asking if something is secure depends on context: you need to know what your goals are and then check if the protocol provides enough protection to achieve these goals.
This is also my problem with these generic examples or wrapper classes; they make no sense to me, as the generic security that they seem to provide may not fit your use case; I'd rather design a protocol specific to the use case.
I understand this question may seem better-suited for Crypto.SE or Security.SE; I'm asking it here because I'm specifically asking for help with the API rather than asking for technical or historic background.
I'm currently looking at integrating libsodium into one of my projects via PyNaCl. Having scanned the docs for both these projects (admittedly not super thoroughly), it doesn't look to me like there's a way to use an a cipher other than Salsa20, the default.
This doesn't pose an immediate problem for me since Salsa20 seems to be both reasonably secure as well as being performant, but in the future, I may want to use a different algorithm. Is this kind of toggle provided by either library (and ideally at the PyNaCl level)?
The box operation just performs a scalar multiplication in order to get the shared secret, and then performs authenticated encryption using that secret.
The former is done with the scalarmult API, that you can call manually to get the same key as the one box would compute.
The later is the secretstream API, that you can also call manually using the shared key from the previous step.
Libsodium has a slightly better key exchange API: kx (crypto_kx) that you can use for the first step.
And for the symmetric operation, it also provides alternatives to XSalsa20 (-Poly1305), in particular in the AEAD APIs: XChaCha20 (-Poly1305), AES-256 (-GCM) and AEGIS-256.
But, really, there is nothing wrong with XSalsa20. It has a comfortable security margin, and its large nonce size is very convenient.
I need to implement an authentication procedure between a reader an NFC tag but being my knowledge limited in this area I will appreciated some aid in order to understand few concepts.
Pardon in advance for rewrite the Bible but I could not summarize it more.
There are many tags families ( ICODE, MIFARE, NTAG...) but after doing a research I think NTAG 424 DNA matches my requirements(I need mainly authentication features).
It comes with AES encryption, CMAC protocol and 3-pass-authentication system and here is when I started to need assistance.
AES -> As I am concerned this is a block cipher to encrypt plain texts via permutations and mapping. Is a symmetric standard and it does not use the master key, instead session keys are used being them derivations from the master key. (Q01: What I do not know is where this keys are stored in the tag. Keys must be stored on specialized HW but no tag "specs" remark this, apart from MIFARE SAM labels.)
CMAC -> It is an alteration of CBC-MAC to make authentication secure for dynamically sized messages. If data is not confidential then MAC can be used on plain-texts to verify them, but to gain confidentiality and authentication features "Encrypt-than-mac" must be pursuit. Here also session keys are used, but not the same keys used in the encryption step.(Q02: The overall view of CMAC may be a protocol to implement verification along with confidentiality, this is my opinion and could be wrong.)
3-pass-protocol -> ISO/IEC 9798-2 norm where tag and reader are mutually verified. It may also use MAC along with session keys to achieve this task.(Q03: I think this is the upper layer of all the system to verify tags and readers. The "3 pass protocol" relays in MAC to be functional and, if confidentiality features are also needed, then CMAC might be used instead of single MAC. CMAC needs AES to be functional, applying session keys on each step. Please correct me if I am posting savages mistakes)
/*********/
P.S: I am aware that this is a coding related forum but surely I can find here someone with more knowledge than me about cryptography to answer this questions.
P.S.S: I totally do not know where master and session keys are kept in the Tag side. Have they need to be include by a separate HW along with the main NFC circuit ?
(Target)
This is to implement a mutual verification process between tag and reader, using the NTAG 424 DNA TagTamper label. (The target is to avoid 3ยบ parties copies, being authentication the predominant part instead of message confidentiality)
Lack of knowledge of cryptography and trying to understand how AES, CMAC and the mutual authentication are used on this NTAG.
(Extra Info)
NTAG 424 DNA TT: https://www.nxp.com/products/identification-security/rfid/nfc-hf/ntag/ntag-for-tags-labels/ntag-424-dna-424-dna-tagtamper-advanced-security-and-privacy-for-trusted-iot-applications:NTAG424DNA
ISO 9798-2: http://bcc.portal.gov.bd/sites/default/files/files/bcc.portal.gov.bd/page/adeaf3e5_cc55_4222_8767_f26bcaec3f70/ISO_IEC_9798-2.pdf
3-pass-authentication:https://prezi.com/p/rk6rhd03jjo5/3-pass-mutual-authentication/
Keys storage HW:https://www.microchip.com/design-centers/security-ics/cryptoauthentication
The NTAG424 chips are not particularly easy to use, but they offer some nice features which can be used for different security applications. However one important thing to note, is that although it heavily relies on encryption, from an implementation side, that is not the main challenge, because all of the aes encryption, cmac computation and so on is already available as some sort of package or library in most programming languages. Some examples are even given by nxp in their application note. For example in python you will be able to use the AES package from Crypto.Cipher import AES as stated in one of the examples of the application note.
My advice is to simply retrace their personalization example beginning at the initial authentication, and then work your way up to whatever you are trying to achieve. It is also possible to use these examples in order to test the encryption and the building of apdu commands. Most of the work is not hard, but sometimes the NXP documents can be a bit confusing.
One small note, if you are working with python, there is some code available on github which you might be able to reuse.
For iOS, I'm working on a library for DNA communication, NfcDnaKit:
https://github.com/johnnyb/nfc-dna-kit
Say I have some data and a password, and I want to encrypt the data in such a way that it can only be recovered with the right password.
How does this technically work (i.e. how to implement this)? I often hear people use bitshifting for encryption, but how do you base that on a password? How does password-based encryption work?
An example is Mac OS X FileVault
Thanks.
If you give sample code, preferably in C, Objective-C or pseudocode.
For (symmetric) encryption you need a secret key for encryption and decryption.
Usually, the password you supply is used as the source of this key. For various security reasons, the password is not (and often cannot, due to requirements of the cipher used) directly used as the key. Instead, a key derivation function is used to generate the key from the password.
This is why passwords for encryption must be long and fairly random: Otherwise the resulting key will only come from a very small subset of possible keys, and these can then simply all be tried, thus brute-forcing the encryption.
As to code examples, there are several possibilities:
look at the source code of a crypto library, such as OpenSSL
look at the source code of a program that implements encryption, such as GnuPG
google some sample source code for a simple encryption algorithm, or a key derivation function, and try to understand it
This depends on what you want to learn.
You'll need to look to other resources for a deep explanation, as this question is extremely broad.
Speaking generally: you use a password as a "seed" for an encryption key, as sleske pointed out. Then you use this key to apply a two-way encryption algorithm (i.e. one that can be applied once to encrypt and again to decrypt). When you apply the algorithm to a piece of data, it becomes encrypted in such a way that you could never get the data back out again without using the same key, and you can't practically produce the same key without having the same password as a seed.
If you're interested in crypto, read Applied Cryptography by Bruce Schneier. Excellent read, lots of examples. It goes through many different cryptography types.
An easy way, but not exactly secure, is to rotate each byte by a number determined by the password. You can use a hash code from a string, or count the number of characters, or whatever for the number.
What you are probably thinking of, though, is public key encryption. Here is a link to a document that will tell you the math for it - you'll have to work out the implementation details yourself, but it's not that hard once you understand the math.
http://mathaware.org/mam/06/Kaliski.pdf
The basic building block of most block ciphers is a construction called a Feistel Network. It's reasonably easy to understand.
Stream ciphers are even simpler - they're essentially just pseudo-random number generators, albeit with some important security properties, where the initial internal state is derived from the key.
Password based encryption IS symmetric. The input usually consists of a salt in addition to the password. FooBabel has a cool app where you can play around with this... currently they hard code the Salt to an array of eight bytes (zero to seven) for simplicity. I put in a request to see that they let users input the salt. Anyway, here it is - PBECrypto
I want to send an out of band message (don't worry about how it gets there) to a program I've written on a distant machine. I want the program to have some confidence the message is legit by attaching a digital signature to the message. The message will be small less than 200 characters.
It seems a public key based signature is what I want to use. I could embed the public key in the program.
I understand that the program would be vulnerable to attack by anyone who modifies it BUT I'm not too worried about that. The consequences are not dire.
I've looked through the MSDN and around the web but the prospect of diving in is daunting. I'm writing in straight c++, no NET framework or other fancy stuff. I've had no experience including NET framework stuff and little luck during previous attempts.
Can anyone point me at some very basic resources to get me started?
I want to know
How to generate the public and private keys
How to sign the message
How to verify the signature
You could try looking at the Keyczar library. It provides a high level abstraction to cryptographic functions with the aim to make is easy for developers to do crypto correctly. As an added bonus it has c++ bindings.
There is also Cryptlib which has been around for a while, and NaCl. As with Keyczar these libraries aim to provide a high level abstraction for common crypto functions.
gpgme is a high-level cryptographic API for GnuPG, written in C, but with bindings for a number of languages. GnuPG has excellent docs and is easy to use, so you can play around 'manually' on the command line and get a feel for how the key operations work, then look up the functions you need for your code in the API.