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    Cryptography Video Steganography on Youtube?

    December 19, 2018

    Cryptography Video Steganography on Youtube?

    Video Steganography on Youtube?

    Posted: 18 Dec 2018 06:10 PM PST

    Not technically cryptography, but hiding data can certainly aid in the protection of said data, especially if the data is further protected by a modern encryption algorithm. That said, onto the question:

    Would it be possible to use steganography to hide meaningful amounts of data in a video and retain that data if it were uploaded to YouTube? Would YouTube compression possibly interfere with the hidden data? If technically possible, would it be a viable method of hiding data you wanted available to anyone who knew where to look and, if applicable, knew how to decrypt the data?

    And, if possible or viable, do you think it's common? Perhaps using those copious low-quality text to speech videos?

    submitted by /u/prefrontalobotomy
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    Data file produced by /dev/urandom fails Dieharder, but piped input does not?

    Posted: 18 Dec 2018 02:00 PM PST

    I'm not really sure what I'm doing to be honest, but I am trying out using dieharder. I used the '-g 200' function to test /dev/urandom by pipe and it passed all tests. But a file produced by the same /dev/urandom file fails many of the tests the standard input passed.

    cat /dev/urandom | dieharder -a -g 200

    vs

    dd if=/dev/urandom of=./random_file bs=1M count=1 dieharder -a -g 201 -f random_file

    Am I doing something wrong?

    submitted by /u/kennbr
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    On Ghost Users and Messaging Backdoors – A Few Thoughts on Cryptographic Engineering

    Posted: 18 Dec 2018 06:43 AM PST

    Modular Inverse in GF 2^8

    Posted: 18 Dec 2018 12:47 PM PST

    RSA Tools

    Posted: 18 Dec 2018 03:18 PM PST

    What tools can I use to encrypt / decrypt messages using RSA. I need to generate keys, encrypt, and decrypt.

    submitted by /u/Mortem_1
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    What is the proper way to use NaCl's Box Encryption / am I doing something horribly wrong?

    Posted: 18 Dec 2018 03:16 AM PST

    This is a follow up to https://www.reddit.com/r/crypto/comments/a709vx/how_does_signing_come_into_play_with_public_key/ec119mj/?context=3

    Where I got the feeling that my current way of encrypting may not match up with the intent of box encryption.

    For some background / what my app is currently doing,

    ​

    Given two people, Alice and Bob, who know each other outside my app, https://emberclear.io

    want to talk. They have not spoken before, and therefore do not have each other's public keys.
    When on emberclear, the server knows their public key -- this is currently used as the websocket channel for a particular user.
    The server cannot know that Alice and Bob want to talk to each other, all the server does is relay messages incoming from one websocket channel (named `alicePublicKey`) with the format `{ to: bobPublicKey, ciphertext: ...}` to the websocket channel for `bobPublicKey`.

    since Alice and Bob do not yet know each other's public keys, they must do a key exchange out of band. So, Alice will send Bob her public key either through some other platform (via a link such as https://emberclear.io/invite?name=NullVoxPopuli&publicKey=bcd75a243e988bdfb9b19aaf1d3af2b7a02826a7a94c4ed2915481f825dddf62 ), or physically in person via QR Code.
    Once bob clicks the link, a message is sent to Alice so that she now has Bob's public key.

    Normal chatting may resume from there.

    The goal of this technique is to not trust servers, and have most of logic on the client side.
    I'm aware there are other privacy-focused chat programs out there... this is a side project, for fun. :)

    From the thread linked at the top of this post, it seems that I may only be using half of Box.
    - Signing / verifying doesn't matter because keys are exchanged once / the same public / private keys are used for every message (I don't think this was explained well in the other thread)
    - Is key exchange *supposed* to happen more often than once per set of 2 people?
    - Is there anything that I could be doing wrong?

    submitted by /u/DerNalia
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    How do I get on with the implementation of Elliptic Curve Cryptography on Images?

    Posted: 18 Dec 2018 08:08 AM PST

    A little bit of a background here. I am final year engineering student and my branch is Electronics and Telecommunications. My final year project is Image Encryption using Elliptic Curve Cryptography, and I must admit that I am very new to Cryptography, and not a big fan of maths which constitutes a large part of Elliptic Curve Cryptography.
    I studied Number Theory, Finite Fields, RSA, Diffie Hellman, just to understand the background of Elliptic Curves. Theoretically, I understand it very well. But I am struggling to proceed with the implementation. Any tips/tricks/resources in this regard would be of great use.

    I am specifically looking for implementation details/libraries/languages that would be ideal for this since I've already taken a big plunge forward by choosing a cryptographic project.

    Thanks in advance

    submitted by /u/postrock20
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    Building a Private Currency Service Using Exonum with Zero-knowledge proofs (ZKP)

    Posted: 18 Dec 2018 05:11 AM PST

    Please can you fill in this questionnaire

    Posted: 18 Dec 2018 03:23 AM PST

    Password recovery on Block-chain ( Hyperledger sawtooth in this case).

    Posted: 17 Dec 2018 05:34 PM PST

    I am using bip39 specifications for 24 word mnemonic, Whenever user registers

    with his/her password, A Scrypt key is generated from this password and used to

    encrypt this mnemonic, The admin of the database in this way, cant decrypt it to see it.

    ​

    Lets say a user forgots his/her password, there is no way to recover his/her mnemonic.

    One way is to design a mechanis in which he/she can share their mnemonic with other

    users on the blockchain.

    The mnemonic is broken down into lets say, 5 shamir secrets out of which, three are

    necessary to recover the original mnemonic.

    ​

    Since all the other accounts are already present on the blockchain, their account

    has a "public" key which has the actual publick key from which this account

    address was generated. The brief outline of accounts on blockchain is like this

    ​

    public: hex encoded secp256k1 key from which this address was generated

    created_on: timestamp

    email: sha256 hash of email id

    phone_number: sha256 of phone_number

    secret_shared: list of public keys corresponding to random indexes

    the length of list is dependent upon the number of users with

    whom the mnemonic will be shared

    ​

    The user at the time of registration creates five random indexes out of 2**32

    and gets his public/private key pairs corresponding to these indexes. From

    these public keys it generates a different kind of address, lets say

    secret_sharing_address, The user then encrypts each shamir secret with other users

    accounts public keys.

    ​

    encrypted_shamir_secret: encrypted_shamir_secret

    shared_with: other user account address

    is_live: False

    new_key: null

    updated_on: latest timestamp when this contract was changed

    updated_secret: False

    ​

    for argument, Lets say these are the only keys. Five transaction of this kind

    for five sifferent users will be floated.

    ​

    Lets say the user forgots his/her password one day, he enters his email and

    a new password.(The ownership of email can be chacked with OTP etc)

    Two things will be calculated from these details

    1. The sha256 hash of the email.

    2. A new scrypt key from this new password.

    This hash will then be searched in the blockchain, if a matching account is found,

    The secret_shared key will be fetched.

    secret_sharing_address addresses will be generated from each of these public addresses,

    and then on each address, the key

    "is_live": True

    "new_key": Encrypted with corresponding public key (scrypt key)

    ​

    Now since these are directed to different users, as soon as they will see

    is_live is active, they will decrypt thir share with their private key and also

    the scrypt key. They then encrypt the secret with this decrypted scrypt key.

    ​

    Each user will now again change the contract state and set these key

    updated_on

    updated_secret: share encypted with scrypt key

    ​

    as soon as the threshold of three users will be reached, Our user

    will intiate recover password process, in which he again enter the new password

    decrypts all the shared secrets, combine them , recovers original mnemonic

    and then encrypts it again with this scrypt key and stores into the database.

    ​

    Advantages:

    1. No association can be drawn from secret_sharing_addresses, so no user

    who is participating in this process can identify other user.

    1. No one user can recover the mnemonic alone.

    2. The Database administrator couldnt see the original mnemonic on the

    entire process.

    ​

    Note: My limited encryption knowledge only took me this far, Please help me to refine this process. If its totally junk, please let me know bluntly.

    submitted by /u/graphicaldot
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