apple iphone -- sha256 encrypt/decrypt --how?

[bruce]

Hey/Hi.

I don't have access to an iphone. Anyone with an iphone able to tell
me how you'd encrypt/decrypt sha256 text?

IE, if I encrypt sha256 on a linux platform, and let someone with
iphone decrypt it.

thanks

[Gerard Dupont III]

If it’s just text, there are a number of apps in the App Store if they search for “sha256”. I tested this app just now and it works as expected. Doesn’t do files.. 

https://apps.apple.com/us/app/hash-calculator/id655753093

Sent from my iPhone

On Sep 11, 2021, at 6:05 PM, bruce <bado...@gmail.com> wrote:

Hey/Hi.

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[Marcin Polewski]

SHA-256, which is part of the SHA-2 family of algorithms is NOT an encryption/decryption algorithm. Instead it is a one-way digest (aka hashing algorithm). Given any input data, it produces a 256 bit (32 bytes) hash of the input data. The process of reversing hashed data to it's corresponding input data is not possible.

See more information here:

https://en.m.wikipedia.org/wiki/SHA-2

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[d.s.]

Probably the simplest I can suggest is to use GnuPGP/GPG. There are apps for ios (here is one https://pgpro.app/) and there are a bunch of utilities to deal with openpgp crypto stuff.

sha256 is not an encryption method. Its a digest, a one way function that generates a unique repeatable checksum of a data stream.

sha256 or other hash functions are used in conjunction with public-key infrastructure to provide a way to prove to the receiver that the sent data was generated by the expected sender. No encryption happens here. This whole mess thing is referred to as HMAC.

Encryption happens with things like AES, Blowfish, etc.

[bruce]

hi guys.

Thanks for the reply.. I was typing sha256.. while I meant openssl 256... doh!!

but from everything you guys said, it's trivial to handle on iphone..
i thought it would be, but didn't see anything on 1st glance.

thanks much.

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[Marcin Polewski]

Your question about "openssl 256" is still too ambiguous

• "openssl" is a software library containing many-many utilities and algorithms
• "256" in terms of cryptography usually means output block size of 256 bits (aka 32 bytes)

So putting the two together is analogous to asking about "GPG 256" or "TensorFlow 256", which are also ambiguous.

Which exact algorithm from the OpenSSL library is your data encrypted or encoded with?

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[bruce]

my test

openssl enc -aes-256-cbc -salt -in jen1.txt -out jen1.dat

openssl enc -aes-256-cbc -d -in jen1.dat

generates a key + the encrypted file for decryption

this is fine for now...

thanks!

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