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46

SHA-512 PROS: Due to the avalanche effect, every single modification to the suffix will change the SHA512 sum entirely. This means that from one N first letters of one hash you can't say anything about the N first letters of another hash, making your passwords quite independent. SHA512 is a one-way compression function, so you can't deduce the password ...


42

From a usability standpoint, it's awful. You need to generate a hash each time you want to log in. Even using a password manager to look up truly random strings would be less work. From a security perspective, you have combined the problems of hashing client-side and using a password pattern: Yes, using a password hash on the client-side means that your ...


10

I think you're not too far from a possible solution (aka using a modern KDF and effectively treating this like a password). However, there are some more considerations (which were already mentioned in comments): SSNs have very low entropy, which means that brute-force is an especially easy attack Since you need to find if the SSN has been used anywhere, ...


7

One of the main purposes of your scheme is to prevent access to all of your accounts if one password is compromised. While it's better than simple password reuse, it is still easily bypassed by an attacker and imho doesn't add enough value to justify the added complexity. As you mention that you want to focus on the cryptographic properties: sha512 is an ...


4

The comments have ping-ponged around making it difficult to see the whole. Rather than play whack-a-mole, here is a summary. First, let's remember that any password scheme must improve on best practice. Best practice is to use a good password manager with a good password generator. Let's also remember that security is only as strong as its weakest link. It ...


3

The length of the base64 value that you posted is 20 bytes (160 bits), so it very well could be a SHA1 hash, as SHA1 hashes are 160 bits in length. The 20 bytes that you posted in base64 format equate to the following in hexadecimal format: be fd f9 f4 c7 97 43 e1 a0 b0 41 59 a5 fd 0d a3 81 d7 c4 28


2

It is never zero, there is always a probability that there are many files that have the same hash value due to the pigeonhole principle and almost uniform distribution of the output of the cryptographic hash functions. This can be understand by the arbitrary input size of the hash function but fixed output size, like MD5 has 128-bit and SHA-1 has 160-bit ...


2

The different images displayed by the two SHAttered PDFs is due entirely to a single byte located at offset 192, which is "\x73" in shattered-1.pdf and "\x7f" in shattered-2.pdf. This byte forms the second part of a two-byte big endian integer that defines the length of a COM ("Comment") segment within the JPEG image stream. Bytes contained in a COM segment ...


2

You're conflating two things, which is why you are confused about them. Let's pick both HTTPS and SHA-512 apart and then things will be much clearer. What does a hash offer me? A hash algorithm is a way for a program to take some arbitrarily large input and return a (usually small) fixed output. For example, a program can have several GB of data, but the ...


1

Signing is one of two basic operations you can perform in public key cryptography: encryption: encrypt with recipient's public key, decrypt with matching private key signature: sign with sender's private key, verify with matching public key The goal of digital signatures using private keys is to ensure that the message is as intended by the signer and not ...


1

hashcat wont do this for you, you need to extract the fields you want using the seperator (-p) and ignore username (--username) switches might help, but you are going to have to get the text into a format hashcat understands first. looking at your extract there are 25 fields: 9 empty 4 username/email 4 Hex SHA1 hashes 3 single digits 2 timestamps an 11 ...


1

personally i just truncated a 512bit blake2b to 160 bits, with blake2b being faster than MD5, SHA-1, SHA-2, and SHA-3 for amd64 and ARM processors, and having a security margin comparable to SHA-3 (and it's predecessor BLAKE was a SHA3 finalist along with the SHA-3 winner Keccak), it's an excellent replacement for SHA1 imo. btw i did some birthday collision ...


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