Hello everyone

I am implementing PKI

what I understood in PKI is

Public key encrypts data

file.txt ==Pubkey ====>#$$#$#$#$#$ ===Private key(Alice)==>file.txt ALICE
BOB



My question is it possible in reverse direction



file22.txt <===Pubkey ===#$$#$#$#$#$<====Prikey(Alice)==file22.txt ALICE
BOB

Can Alice encrypt data with her (private key) and BOB can decrypt it with
Alice Public key

Like in signature


#### <===Pubkey===^&^&%$%$%$<===Prikey=====####<==MD5==file22.txt ALICE
BOB
file22.txt <============================ file22.txt

The keys just have to match, you can use the same key everywhere. This, of course, isn't incredibly secure, but it will accomplish what you're wanting.

What you're asking for is not the default behavior, so one could say, "No, it doesn't work that way." However, there's nothing stopping you from using the same private key for both alice and bob.