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Encryption using a key derived from a password or passphrase entered by the user.

0
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2answers
64 views

Does this “protocol” ensure only the users may learn the secret data?

EDIT: I have only left this as historic question asking, please see my proposed Answer below as a better protocol, since the original question was very broken. I need to build a website where one ...
1
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1answer
50 views

Does having an SHA256 hash compromise PBKDF2 secrecy?

If I have a password pwd, and I hash it with SHA256 and send it to a server for authentication (server will apply ...
0
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0answers
35 views

encrypting data in 1 database table with user's password

In an existing web-application i want to encrypt data in one database table for 1 particular user. goal: better protection of the data in general as some of it is more sensitive than simply personal ...
2
votes
1answer
43 views

Password protection in ARJ: 3 characters of password are retrievable

On this site there is information that one can know first 3 characters (bytes) of the password without brute force. I know that ARJ in older versions has very simple encryption, i.e. XOR with ...
0
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1answer
30 views

Perform calculation on encrypted numbers

What i am trying to achieve ? I am developing a carpooling solution powered by Blockchain and IOT. This one is supposed to be technically convenient and without compromising on the privacy part. ...
0
votes
1answer
26 views

In SRP, is the client protected from server impersonation?

Assume use of SRP over an otherwise insecure unauthenticated channel where the user running the client side has chosen a password, the user only uses that password with a trusted SRP client software, ...
1
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2answers
47 views

Mechanism of PBKDF in encryption key generation with passphrase

I want to roughly understand how the mechanism works of generating an encryption key from a passphrase, by which we encrypt a volume or file. I'm familiar with public key encryption, the concept of a ...
3
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0answers
51 views

Did “The Catena Password-Scrambling Framework” make an error in the reduction of its pseudorandomness?

I was reviewing the most recent version of the Catena paper and they made some claims that I find questionable in their reduction of the pseudorandomness of the output of Catena (p. 32). First I will ...
1
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2answers
116 views

Zencash uses your passphrase to identify AND unlock a wallet - how is this secure?

When looking into Zencash I stumbled into myzenwallet.io (by the Zencash creators), which gives you the option to enter a passphrase to generate a wallet (seems normal), but then after creating your ...
2
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1answer
68 views

How much time would it take to crack time mnemonic phrases in these scenarios?

How long time would it realistically take to crack each of following scenarios and how many combinations does each scenario consist of? Mnemonic Phrase, it is not known if we are looking for a pass-...
0
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2answers
73 views

Does AES-GCM without security tag turn into regular CTR Mode?

We are looking to implement a simple password based key agreement scheme. Part of this is deriving a symmetric key from a common passphrase known to both parties involved. This symmetric key is then ...
1
vote
1answer
134 views

Would it be safe to store GCM nonce in the encrypted output?

I'm looking to use AES-256 GCM to encrypt and authenticate a file containing sensitive information. I am a bit loss on where to store the nonce that is required for GCM. Would it be adequate/safe to ...
0
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0answers
31 views

Authorizing someone to open Alice's lock when Alice's lock only has Alice's public key

I'm designing a lock and I want Alice to be able to give temporary permission to someone to open the lock. After a set amount of 'access time' that someone should not have access to open the lock ...
1
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0answers
45 views

Flaw in Philip MacKenzie's PAK security proof

Maybe the security proofs in the paper "The PAK suite: Protocols for Password-Authenticated Key Exchange (2002)" from Philip MacKenzie are wrong. The fault is shown for the PAK protocol (ch. 6.2) ...
2
votes
1answer
189 views

Key recovery after AES-ECB encryption of two blocks with some known plaintext/ciphertext

I am analysing a small, bespoke end-to-end encryption service's source code, in particular their user registration process. I am finding some interesting things going on and I am wondering if there's ...
0
votes
1answer
179 views

Which cipher to use with openssl for shortest output?

I'd like to encrypt my 12-24 words seed for my bitcoin wallet with openssl command line tool to be able to have it with me on paper without the risk that somebody could use it Which cipher should I ...
1
vote
3answers
2k views

What's the difference between PBKDF2 and HMAC-SHA256 in security?

Being a software developer, I haven't dealt with crypto so far. So I know very little, sorry for that already. I am aware that you should use bcrypt, scrypt, Argon2 or PBKDF2 for generating a hash ...
4
votes
3answers
1k views

Password-based cipher with fast encryption

Define a password-based cipher as a cipher which decryption key is a humanly memorable password, thus optimistically at most 28 to 44 bits of entropy (per the obligatory XKCD). For a password-based ...
0
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2answers
29 views

Prevent communication with a node assuming full transparency

I have an IoT device that I have set up to communicate with AES-256-GCM encryption. The working version has the encryption key stored in plaintext in a file on the device (this is going to be improved)...
-1
votes
2answers
85 views

What is the difference between algorithm and passphrase?

If there is an algorithm securing a document, then why is there also a passphrase when the algorithm is already there? And if there is a passphrase securing a document, then why do we also use the ...
1
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0answers
110 views

An efficient SPEKE protocol with curve25519

SPEKE is a very simple and elegant PAKE protocol. I think, one of the reasons why PACE has been invented and is now the ICAO protocol, is because SPEKE was patented. Fortunately, the SPEKE patent ...
1
vote
1answer
94 views

An efficient PACE protocol with curve25519

The PACE protocol is a password authenticated key agreement which is widely used. For instance, in the electronic ICAO passports as the so called SAC protocol. PACE is standardised in ICAO DOC9303 ...
3
votes
1answer
153 views

I am trying to create a simple image encryptor in python result isnt promising [closed]

I am writing a program in python (myself) to encrypt images. I don't want or expect it to be state of the art encryption and safe at the end but i have a problem. The result encrypted image still has ...
0
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1answer
109 views

Secret Key Exchange and FIPS or Industry Standard Compliance

I am trying to collect several information regarding Security Industry Standards and the FIPS compliance to meet the security standards for our future development system. In this case, we have two ...
0
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1answer
214 views

Can a Password be Derived from a AES key?

This thought randomly popped into my head and I have not been able to find a clear, defined answer for it. Given an AES key, lets say an AES-256 key which is derived from a user password, is there any ...
4
votes
1answer
140 views

Password derived hash to encrypt known plaintext as password check

The title sounds way too adventurous for what it actually is. I am currently building a system which features some encryption. There is already a system in place, which is built after that scheme if ...
-1
votes
1answer
477 views

Best complementary algorithm to AES

I'm looking to protect sensitive data from deletion by hosting it on Amazon Glacier. I'd like to secure that data against possible hacks of Amazon by encrypting it, and I'd like for the data to be ...
1
vote
1answer
387 views

What is the best way to derive a encryption key from the serial number?

I have a couple of Android devices which run my app. Every device has it's own unique serial number - a hex string 16 characters long. The app needs files, which usually reside on external SD. These ...
-3
votes
1answer
351 views

How important is length and complexity of personal password for AES-256 encryption?

I want ask you how important is to have complicated personal password for AES-256 crypto? For example if I use these two "types" of passwords: pass123 ...
0
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2answers
109 views

Will knowing clear text value behind encrypted data help hacker find password?

I am building an Android App where I will be storing some encrypted data in a database. To ensure that the user has entered the right password, I have encrypted my own secret phrase and stored it in ...
1
vote
1answer
528 views

How much time will it take to brute force a password

I am building a client-side app that will encrypt data, using password-based key generation, into the database. Can someone verify my calculations to figure out what is the right number of iterations ...
1
vote
2answers
453 views

UNIX password scheme and encryption function

Recent versions of Unix store encrypted passwords in a file that is not publicly accessible. Such files are called shadow password files. In the UNIX password scheme, if only the operating system and ...
4
votes
3answers
630 views

Does encrypting data multiple times using different passwords increase security?

Does encrypting plain-text data multiple times using different passwords provide a greater level of security? If so, what encryption algorithm would be best for such a use? Would it be beneficial to ...
1
vote
1answer
297 views

Question about hashing passwords with PBKDF2

I am new here and new to encrypting and securing passwords, so please forgive me if this question is not posted to the right location or if my question is bad. I have been working on a web app in ...
-1
votes
1answer
97 views

New Passwording? [closed]

I just want to note before you continue reading--this does not specifically apply to hashes or the key to encrypted messages. However, I am initially thinking about password/key solving/remembering by ...
4
votes
1answer
319 views

Can key hardening compensate lack of entropy?

In the context of an offline brute-force attack on encrypted data at rest (say, a password-protected AES encrypted file), is a password with 64 bits of entropy and 65536 rounds of key hardening just ...
16
votes
2answers
505 views

Is there any SRP-like key exchange only using “standard” cryptographic primitives?

I am looking into PAKEs (password-authenticated key exchanges), and it seems like SRP (Secure Remote Password) is essentially the de-facto standard. However, implementing SRP actually requires doing ...
0
votes
1answer
63 views

Are there any downsides to key stretching an already high quality entropic key?

For example, if we grab 50 bytes from a high quality source and run them through a key stretching function like Argon2 and have it generate a 32 byte secret for AES. Is there any downside to this? Do ...
3
votes
0answers
85 views

SPAKE2 - Pairwise keys with multiple participants

With magic wormhole, I've discovered SPAKE(2) and I was wondering if it is possible to derive pairwise shared keys between multiple participants still using one password only. More precisely, amongst ...
1
vote
1answer
515 views

storing salt in app

I want to create a key for my realm database wich work with AES-256 and for encryption wants a byte[64] key. I read this good question about create a key from 4 ...
1
vote
1answer
119 views

securing the keystore

When generating a public-private key pair you have the option to secure the keystore with a password. where is that password stored, is it a hashed version that is stored and if that is so which ...
15
votes
4answers
13k views

Is password-based AES encryption secure at all?

For a few years I have put all my passwords in a text file and encrypted that file with a password using a software solution (Axcrypt) which uses AES-128. The password is not really strong, but I ...
2
votes
1answer
545 views

Database and End to End encryption

I'm currently designing a mobile/desktop application synchronise some messages or notes. I'm searching a way to secure it and to avoid let the server being able to read the messages. My goal is have ...
2
votes
1answer
499 views

Encryption in popular compression file formats - 7zip, RAR, Zip

When encrypting a file say with Winrar you have to enter a password. I am under the impression that this password is not stored anywhere but instead the password together with some other attributes ...
0
votes
1answer
621 views

Encrypt without password, decrypt only with password

I'm trying to implement a password manager and I want to achieve this behaviour. User enters a master password once (eg. when the program is first run) and a key/hash of some sort is derived and ...
1
vote
1answer
125 views

Problems when using PBKDF2 to create an ECDSA private key from a password?

System based on, e.g.: PBKDF2, ECDSA and authenticator's random challenges. Key derived from a password would be ECDSA's private key used to sign random challenges. Is password brute force the only ...
3
votes
1answer
311 views

Multiple users getting access to same (secret) encryption key on a single computer?

I am developing an application for Desktop PCs (Mac primarily, Windows later) that uses an encrypted SQLite database. I want to give multiple authenticated users access to this "main" database. I like ...
3
votes
3answers
6k views

Best way to generate a IV for AES-CBC when encrypting files?

The situation is that I want to use symmetric encryption to store some info in files. I'm going to use AES-CBC algorithm. The user is going to remember the password (meaning it will not be stored ...
-1
votes
2answers
96 views

What if I make the hashing with an own function ? Does it make unhackable?

I am thinking to create own hashing Instead of creating encryption(weak). That hash function has some number of cryptic parameters to go before it stores in db? Does it become unhackable if I do so?
1
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2answers
682 views

Multiple passwords per key with any allowing decryption

How to get secret key based on multiple passwords? e.d we have cipher encrypted by combination of passwords "qwe" and "asd", and our purpose to decode the cipher using any of passwords above ...