Merge branch 'main' into fix/generate-simplify

Author: theskyinflames

.github/workflows/lint.yml

@@ -16,7 +16,7 @@ jobs:
       - uses: actions/checkout@v3
       - uses: actions/setup-go@v4
         with:
-          go-version: '1.21'
+          go-version: '1.25'
           cache: false
       - name: golangci-lint
         uses: golangci/golangci-lint-action@v3

.github/workflows/test.yml

@@ -6,10 +6,10 @@ jobs:
     steps:
       - name: Check out code into the Go module directory
         uses: actions/checkout@v4
-      - name: Set up Go 1.21
+      - name: Set up Go 1.25
         uses: actions/setup-go@v5
         with:
-          go-version: '1.21'
+          go-version: '1.25'
           cache: true
       - name: Unit tests
         run: make test

.golangci.yml

@@ -103,7 +103,7 @@ formatters:
   settings:
     goimports:
       local-prefixes:
-        - istio.io/
+        - github.com/theskyinflames/word2png/
   exclusions:
     generated: lax
     paths:

README.md

@@ -43,13 +43,13 @@ To get back the words encoded in the above image, the passphrase is needed:
 <img src="doc/decode.png" alt="encoding" style="width:800px;background-color:white;padding:0px"/>
 
 ## How it works - Encoding
-First of all, the provided words are encrypted using AES-256 encryption in a *chain* mode. I mean, except for the first word, which is encrypted using the provided passphrase, the rest of the words are encrypted using the previous encrypted word as a passphrase. 
+First of all, the provided words are encrypted using AES-256-GCM encryption in a *chain* mode. The encryption key is derived from the passphrase using **Argon2id** (RFC 9106), a memory-hard KDF resistant to GPU/ASIC attacks. A random 16-byte salt is generated for each encryption and prepended to the ciphertext (salt||nonce||encrypted). I mean, except for the first word, which is encrypted using the provided passphrase, the rest of the words are encrypted using the previous encrypted word as a passphrase. 
 
 <img src="doc/ic-encryption.png" alt="Words encryption" style="width:400px;background-color:white;padding:10px"/>
 
 It prevents modifying the sequence of words.
 
-Once we have the words encrypted, we need a bijective function to encode the encrypted words in a sequence of colors in the PNG file. But we also want that this relation between each *byte* and its color depended on the passphrase. So if the passphrase changes, this relation will also change. It's achieved by using the MD5 checksum of the passphrase. It is a 128 bytes signature length, or in other words, it allows to encode 128 values into 128 colors. Here, two bijective functions are built, the first one to encode and the second one to decode: 
+Once we have the words encrypted, we need a bijective function to encode the encrypted words in a sequence of colors in the PNG file. But we also want that this relation between each *byte* and its color depended on the passphrase. So if the passphrase changes, this relation will also change. It's achieved by using an Argon2id-derived key from the passphrase. Here, two bijective functions are built, the first one to encode and the second one to decode:
 
 <img src="doc/bijective.png" alt="Words encryption" style="width:400px;background-color:white;padding:10px"/>
 

cmd/png2word/main.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/alecthomas/kingpin/v2"
 	"github.com/pterm/pterm"
+
 	"github.com/theskyinflames/word2png/lib"
 )
 

cmd/word2png/main.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/alecthomas/kingpin/v2"
 	"github.com/pterm/pterm"
+
 	"github.com/theskyinflames/word2png/lib"
 )
 

go.mod

@@ -1,4 +1,4 @@
-module theskyinflames/word2png
+module github.com/theskyinflames/word2png
 
 go 1.26
 
@@ -8,7 +8,6 @@ require (
 	github.com/alecthomas/kingpin/v2 v2.3.2
 	github.com/pterm/pterm v0.12.69
 	github.com/stretchr/testify v1.8.4
-	github.com/theskyinflames/word2png v0.0.0-20230310162449-716270965f75
 	golang.org/x/crypto v0.52.0
 )
 

go.sum

@@ -70,8 +70,6 @@ github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
 github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
-github.com/theskyinflames/word2png v0.0.0-20230310162449-716270965f75 h1:/v9JPvd6n/3NnGO3dR3km6kO7djJ10H5c6A+44emnyU=
-github.com/theskyinflames/word2png v0.0.0-20230310162449-716270965f75/go.mod h1:sEqjyLcA7jCDiW9eE/KfQKqeaC8+0NV1j5QX4Q+a6Ms=
 github.com/xhit/go-str2duration/v2 v2.1.0 h1:lxklc02Drh6ynqX+DdPyp5pCKLUQpRT8bp8Ydu2Bstc=
 github.com/xhit/go-str2duration/v2 v2.1.0/go.mod h1:ohY8p+0f07DiV6Em5LKB0s2YpLtXVyJfNt1+BlmyAsU=
 github.com/xo/terminfo v0.0.0-20210125001918-ca9a967f8778/go.mod h1:2MuV+tbUrU1zIOPMxZ5EncGwgmMJsa+9ucAQZXxsObs=

lib/aes256_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
+
 	"github.com/theskyinflames/word2png/lib"
 )
 

lib/color_test.go

@@ -4,6 +4,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/require"
+
 	"github.com/theskyinflames/word2png/lib"
 )