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Questions tagged [integrity]

In a cryptographic sense, integrity means unimpaired and complete.

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Get Pixel Data from JPG/JPEG but still bring the integrity? [closed]

As far as I know, JPG is a lossy image compression format Meanwhile, BMP is a generally uncompressed image format, whose file structure consists of bitmapFileHeader (14 bytes) and bitmapInfoHeader (40 ...
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Has reducing MAC size and increasing message size the same effect on security?

I am evaluating ways to reduce the overhead of (H)MACs on small messages. I was primarily wondering if there is a difference between halving the MAC length or keeping the same MAC length but using it ...
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1 answer
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Does CMS AuthEnvelopedData type provide message authentication?

I was looking through the S/MIME Message specification (RFC 8551) to find out what security services it offers. Section 2.4.4 of this document describing AuthEnvelopedData content type (which uses the ...
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INT-CTXT game adversary

I am trying to answer this question. But I think I got it wrong. I am not sure why and how I can improve it. This is the adversary I came up with. Is this correct? ...
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1 vote
4 answers
136 views

Does SSL connection provide integrity?

I'm new to cryptography and I'm trying to implement a secure chat application using OpenSSL. I want to ensure that public messages (which will be shown to all users) cannot be altered during ...
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1 answer
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Quantum secure algorithms

I want to know if the below algorithm , secure against quantum computing attack, and how I can compute the running time for the original algorithm and the proposed attack Source: Yan Zhu, HuaiXi Wang,...
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0 answers
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Prove that secure authenticated encryption system composed with itself is secure

Suppose $(E,D)$ provides authenticated encryption with key space $K$. Define $(E',D')$ with key space $K^2$ as follows: $$ E'((k_1,k_2),m) = E(k_2,E(k_1,m)) \\ D'((k_1,k_2),c) = \begin{cases} D(k_1,E(...
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2 answers
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Is there a way to sign a message so that any subset can be verified?

I would like to know if there's a scheme that can allow something like the following: Alice signs a message $M$ with signature $S$ and gives it to Bob and Mallory. Bob can present any subset of $M$, ...
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1 vote
1 answer
581 views

Can ChaCha20 provide integrity?

I have read that in general stream ciphers do not provide data integrity. Can ChaCha20 be implemented in such a way (perhaps like counter mode with message authentication in AES) to provide this?
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getting key $k_{2}$ somehow definitely compromise authentication scheme and attacker can see cipher text now...so not secure

I was going through this question of nested encryption: Given $\Pi$ = $({Gen}, {Enc}, {Dec})$ is authentication encryption we have designed new scheme $\Pi^{'}$ = $({Gen^{'}}, {Enc{'}}, {Dec{'}})$ ...
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Is the tag in a MAC scheme a fixed size?

I've been reading up on MAC schemes. But I cannot seem to find out whether the tag's that are output by running MAC(m) is of a fixed size? I can find a lot of stuff talking about the tag space being a ...
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1 vote
0 answers
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Is Poly1305 enough for cascading ciphers? [duplicate]

ChaCha20 along with Poly1305 provides confidentiality and integrity. Now suppose I cascade AES on top of ChaCha20. Is it safe to assume that the Poly1305 MAC is still secure, even if I cascade ...
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How can JWE support an integrity check given that it uses a public key to encrypt the message?

As far as I know JWE (JSON Web Encryption) supports both integrity and confidentiality. I agree about the confedintiality because only the recepient with a private key can decrypt a message. What ...
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2 votes
2 answers
133 views

What security guarantees do blockchains provide for data storage?

When it's considered, like here a project where a user needs to store a (small piece of data) on a blockchain what does that really mean from a cryptographer's perspective? What security guarantees ...
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2 votes
1 answer
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MAC forgery using the DES's Complementary Property

I've started reading on MACs and working on a problem where given a MAC construction as $H_0=IV$ and for every $i>0$ $H_i=H_{i−1} \oplus E_{M[i]}(H_{i−1})$ and the tag is $(IV,E_{k_1}(H_ℓ))$, I ...
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6 votes
1 answer
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OpenSSL FIPS integrity check

As far as I know, FIPS requires a set of self tests (POST) to verify the cryptographic algorithms permitted and the integrity of the module. These tests are performed at run-time, so OpenSSL does a ...
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Provable Data Possession

While Provable Data Possession seems to be a very useful and interesting tool for ensuring integrity of data outsourced into Cloud providers, I have never seen a reputed Cloud provider talk about this ...
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1 vote
0 answers
33 views

Integrity for mixture of encrypted/unencrypted database fields

I have multiple blobs each (symmetrically) encrypted with its own randomly generated key. Now I want to encrypt these blob keys with user keys and store them in a database. A table could have the ...
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0 votes
1 answer
126 views

Is MAC process different for symmetric and asymmetric?

Message Authentication Code as far as I know works on the shared secret key. Do they work in the same way. Is there no difference between symmetric and asymmetric processes. Can anyone please explain ...
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0 votes
2 answers
257 views

If I want Integrity and Authentication AND Non-Repudiation, can the Digital Signature be based on the MAC?

Let's say I'm making a digital signature like this: hash = hash(message) digital signature = encrypt_with_private_key(hash) where the private key is Alice's ...
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1 answer
226 views

Boolean XOR function a valid way to verify the integrity of a message

Does the Boolean XOR function represent a valid way to verify the integrity of a message ?
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1 vote
0 answers
50 views

Using cryptography to protect database integrity

I'm designing a micro-services system where each service manages some set of entities (User, Account, e.g). I want to be able to verify the authenticity of entity identifiers (e.g User-Id and Account-...
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2 answers
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How do AES and DES ensure data integrity?

I have been trying to study for cryptographic symmetric algorithms (AES,DES) and came up with a question whether these two on their own ensure integrity (i.e data has not been altered). Do these two ...
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1 vote
2 answers
353 views

Can a MAC be used as a HMAC?

I am reading through an information security book right now, and a confusing question poses itself to me: "Could you use a MAC as a HMAC? That is, does a MAC satisfy the same properties that a ...
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1 vote
1 answer
59 views

Integrity of format preserving Encryption

In this question regarding integrity of FPE, the main point of the answer is that: FFX is not malleable. [...] FFX can provide integrity protection in very limited circumstances. So I was ...
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3 votes
1 answer
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Information security evaluation

I saw this exercise for evaluating the security(confidentiality, integrity, authenticity, and non-repudiation) of some schemes: ENC(M) || SignA(ENC(M)) ...
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1 vote
2 answers
264 views

SHA-3 for Integrity

We used to use CRCs to check the integrity of files. For safety analysis we could associate a probability for detecting a corrupted bit in a large file. Now we are using an RSA Signed SHA-3 hash for ...
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1 vote
0 answers
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Keeping a backup of asymmetric keys with the help of a certificate authority without losing the privacy

First I'll explain the problem, then I will also give a solution(it might be wrong) I've found for it, you let me know what you think about this solution and whether you have a better one. Assume a ...
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2 votes
2 answers
330 views

Does stronger cryptographic hashes also imply being better at verifying integrity?

What I know so far Fact 1) I know that all cryptographic hash functions have the following properties They are many-to-one in nature They produce fixed size outputs Given an output ...
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3 answers
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AES, is this method to say "The password you entered is wrong" secure?

(TL;DR at the end) Let's say the plaintext hello is encrypted with AES (CFB mode). I noticed that decryption works no matter the given password! Of course if the ...
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1 answer
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Best method for checking integrity of 50 GiB files?

I'm making backups of compressed data (using ZPAQ), some compressed archives are large (50 GiB) I was just going to use sha3sum -a 512, for example: ...
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1 vote
1 answer
126 views

How reassuring is CRC-then-XTS as authenticated encryption?

It is known that the "xz" compression format embeds a checksum in the compressed file to verify integrity during decompression or standalone testing. The algorithm of the checksum can be one of: CRC32,...
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230 views

How to validate the authenticity and integrity of an XML document?

I am working on a C++ desktop application that reads an XML (also created by my org) from a public server (does not require authentication). I would like to make sure that the downloaded XML has not ...
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2 votes
1 answer
528 views

How are AEAD, GCM, CBC, Poly1305, EtM, MtE and E&M related?

I am using OpenSSL 1.1.1 to implement a TLS 1.3 communication module so I tried to learn how data integrity and authentication is ensured. I read a lot about AEAD, GCM, CBC, Poly1305, EtM, MtE and E&...
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1 vote
1 answer
113 views

Ensure Data Integrity In An ECDH Key Excange

Been playing around with the inner workings of onion routing and I have a problem. If I wanted to send the 2nd node of a relay network an ephemeral ECC public key, it has to go through node 1, so that ...
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1 vote
0 answers
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SHA256 creates a unique hash for two *.wim that have identical content - are there better methods for verifying *.wim contents? [closed]

I'm trying to verify that the contents of a Windows Image are identical for two WIM files; however, I think the timestamps for the file modifications are affecting the final checksums--even though the ...
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3 votes
2 answers
237 views

Robust authentication and integrity for short OTP message

Using any of the wonders of modern cryptographic technology, how is it possible to package a tweet-sized plaintext, which is to be encrypted with a proper one-time pad, to ensure its integrity and ...
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1 vote
1 answer
275 views

Encrypting more than ~64GiB with AES-GCM - Integrity

I'm looking for solution to encrypt more than acceptable limit ~64GiB under same key with AES-GCM. I know I'm obligated to exchange nonces for each next ~64GiB chunk, but there is one thing that is ...
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2 votes
2 answers
375 views

Does it matter if I publish only publish good or bad MD5 hashes after recovering from a hack?

(This question is a follow-up from another question I asked about MD5, which is why I'm insisting on using MD5 in this question as well) My imaginary Linux distribution, Sushi Linux has had a big ...
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2 votes
0 answers
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Strategies for fast integrity attestation over multi party computation for large messages

I am looking for ways to efficiently perform integrity attestation over large messages using multi party computation. While, hashing (SHA1, 256...) is one alternative but it's painfully slow and grows ...
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2 votes
1 answer
126 views

Authenticated encryption and file data integrity

I've got a task to provide the integrity and an authenticated encryption for files in our application. I need an assurance if my way of thinking is correct. I can't use AES GCM, I have to stay with ...
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2 votes
0 answers
51 views

How to use the wiki UMAC example function?

I want to use the wiki UMAC example to protect the integrity of the communication between 2 devices. Unfortunately I am not quite sure of the meaning of the parameters and I don't want to get it ...
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2 votes
0 answers
40 views

Is there an instance where integrity protecting metadata is bad?

In JWEs there's a unprotected data field as well as recipients are not integrity protected. Is there a case where integrity protecting this data would be a problem? If it doesn't make a difference, ...
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1 vote
1 answer
121 views

Provable data possession (PDP) VS Merkle tree

In the paper Provable Data Possession at Untrusted Stores, there is a mechanism that allows a client to efficiently check if the server still has the client's data. They define two constraints for ...
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0 votes
2 answers
51 views

How a sender will ensure that the public key used for encryption is the key of intended reciver?

Say Alice is the sender and Bob is the receiver. Alice has the public key of Bob and wants to send some data to Bob. How Alice will ensure that the public key she is having is really belongs to Bob?
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5 votes
2 answers
178 views

What's the functional difference between fountain codes and polynomial secret sharing?

Fountain codes, as I understand it, allow for the reconstruction of a set of data (e.g. a 64-bit word), by sending (without corruption or failure) chunks of data generated using a probabilistic ...
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2 votes
1 answer
551 views

File integrity checking: why use a hash tree instead of a hash list?

File sharing systems sometimes use the likes of a Tiger Tree Hash to check the integrity of a file as it is downloaded. Hash trees in general are useful to check integrity of the tree leaves without ...
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2 votes
2 answers
313 views

Can homomorphic encryption offer program integrity and program obfuscation?

By program integrity, I mean the (encrypted) result I receive is indeed the expected result and not, say, an intermediate result or a result affected by an adversary. Can homomorphic encryption defend ...
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0 votes
1 answer
488 views

How to use cryptography to assure data integrity?

I only understand assurance of integrity using a hash function. How to use cryptograpy to assure data integrity?
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0 votes
1 answer
203 views

Authentication and integrity

I was trying to solve this problem: Sometimes Alice needs to send a file to Bob, guaranteeing her identity and the file integrity (no confidentiality required); the two parties are sharing a secret w ...
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