From b9f32d720ae5ec60cadeb492af781ade48cd6cbf Mon Sep 17 00:00:00 2001
From: Quentin Dufour <quentin@deuxfleurs.fr>
Date: Fri, 8 Mar 2024 10:20:45 +0100
Subject: Finalize Aerogramme's refactor

---
 doc/src/crypt-key.md | 82 ----------------------------------------------------
 1 file changed, 82 deletions(-)
 delete mode 100644 doc/src/crypt-key.md

(limited to 'doc/src/crypt-key.md')

diff --git a/doc/src/crypt-key.md b/doc/src/crypt-key.md
deleted file mode 100644
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--- a/doc/src/crypt-key.md
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-# Cryptography & key management
-
-Keys that are used:
-
-- master secret key (for indexes)
-- curve25519 public/private key pair (for incoming mail)
-
-Keys that are stored in K2V under PK `keys`:
-
-- `public`: the public curve25519 key (plain text)
-- `salt`: the 32-byte salt `S` used to calculate digests that index keys below
-- if a password is used, `password:<truncated(128bit) argon2 digest of password using salt S>`:
-  - a 32-byte salt `Skey`
-  - followed a secret box
-  - that is encrypted with a strong argon2 digest of the password (using the salt `Skey`) and a user secret (see below)
-  - that contains the master secret key and the curve25519 private key
-
-User secret: an additionnal secret that is added to the password when deriving the encryption key for the secret box.
-This additionnal secret should not be stored in K2V/S3, so that just knowing a user's password isn't enough to be able
-to decrypt their mailbox (supposing the attacker has a dump of their K2V/S3 bucket).
-This user secret should typically be stored in the LDAP database or just in the configuration file when using
-the static login provider.
-
-Operations:
-
-- **Initialize**(`user_secret`, `password`):
-  - if `"salt"` or `"public"` already exist, BAIL
-  - generate salt `S` (32 random bytes)
-  - generate `public`, `private` (curve25519 keypair)
-  - generate `master` (secretbox secret key)
-  - calculate `digest = argon2_S(password)`
-  - generate salt `Skey` (32 random bytes)
-  - calculate `key = argon2_Skey(user_secret + password)`
-  - serialize `box_contents = (private, master)`
-  - seal box `blob = seal_key(box_contents)`
-  - write `S` at `"salt"`
-  - write `concat(Skey, blob)` at `"password:{hex(digest[..16])}"`
-  - write `public` at `"public"`
-
-- **InitializeWithoutPassword**(`private`, `master`):
-  - if `"salt"` or `"public"` already exist, BAIL
-  - generate salt `S` (32 random bytes)
-  - write `S` at `"salt"`
-  - calculate `public` the public key associated with `private`
-  - write `public` at `"public"`
-
-- **Open**(`user_secret`, `password`):
-  - load `S = read("salt")`
-  - calculate `digest = argon2_S(password)`
-  - load `blob = read("password:{hex(digest[..16])}")
-  - set `Skey = blob[..32]`
-  - calculate `key = argon2_Skey(user_secret + password)`
-  - open secret box `box_contents = open_key(blob[32..])`
-  - retrieve `master` and `private` from `box_contents`
-  - retrieve `public = read("public")`
-
-- **OpenWithoutPassword**(`private`, `master`):
-  - load `public = read("public")`
-  - check that `public` is the correct public key associated with `private`
-
-- **AddPassword**(`user_secret`, `existing_password`, `new_password`):
-  - load `S = read("salt")`
-  - calculate `digest = argon2_S(existing_password)`
-  - load `blob = read("existing_password:{hex(digest[..16])}")
-  - set `Skey = blob[..32]`
-  - calculate `key = argon2_Skey(user_secret + existing_password)`
-  - open secret box `box_contents = open_key(blob[32..])`
-  - retrieve `master` and `private` from `box_contents`
-
-  - calculate `digest_new = argon2_S(new_password)`
-  - generate salt `Skeynew` (32 random bytes)
-  - calculate `key_new = argon2_Skeynew(user_secret + new_password)`
-  - serialize `box_contents_new = (private, master)`
-  - seal box `blob_new = seal_key_new(box_contents_new)`
-  - write `concat(Skeynew, blob_new)` at `"new_password:{hex(digest_new[..16])}"`
-
-- **RemovePassword**(`password`):
-  - load `S = read("salt")`
-  - calculate `digest = argon2_S(existing_password)`
-  - check that `"password:{hex(digest[..16])}"` exists
-  - check that other passwords exist ?? (or not)
-  - delete `"password:{hex(digest[..16])}"`
-- 
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