7 files changed, 315 insertions, 0 deletions
diff --git a/pkg/scrypto/LICENSE b/pkg/scrypto/LICENSE
new file mode 100644
index 0000000..aeafaf4
--- /dev/null
+++ b/pkg/scrypto/LICENSE
@@ -0,0 +1,13 @@
+Copyright (c) 2023-2024 Nicolas Martyanoff <nicolas@n16f.net>
+
+Permission to use, copy, modify, and/or distribute this software for any
+purpose with or without fee is hereby granted, provided that the above
+copyright notice and this permission notice appear in all copies.
+
+THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
+REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
+AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
+INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
+LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
+OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
+PERFORMANCE OF THIS SOFTWARE.
diff --git a/pkg/scrypto/README.md b/pkg/scrypto/README.md
new file mode 100644
index 0000000..e83bc8e
--- /dev/null
+++ b/pkg/scrypto/README.md
@@ -0,0 +1,5 @@
+Original code imported from https://github.com/galdor/go-service/tree/master/pkg/scrypto
+
+Alterations:
+- converted the EncryptAES256 and DecryptAES256 functions to methods
+- rewrote the tests to get rid of the dependency on testify
diff --git a/pkg/scrypto/aes256.go b/pkg/scrypto/aes256.go
new file mode 100644
index 0000000..27a39d6
--- /dev/null
+++ b/pkg/scrypto/aes256.go
@@ -0,0 +1,138 @@
+package scrypto
+
+import (
+	"bytes"
+	"crypto/aes"
+	"crypto/cipher"
+	"crypto/rand"
+	"encoding/base64"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+)
+
+type AES256Key [32]byte
+
+const (
+	AES256IVSize int = aes.BlockSize
+)
+
+var Zero = AES256Key{}
+
+func (key *AES256Key) Bytes() []byte {
+	return key[:]
+}
+
+func (key *AES256Key) IsZero() bool {
+	return bytes.Equal(key.Bytes(), Zero.Bytes())
+}
+
+func (key *AES256Key) Hex() string {
+	return hex.EncodeToString(key[:])
+}
+
+func (key *AES256Key) FromHex(s string) error {
+	data, err := hex.DecodeString(s)
+	if err != nil {
+		return err
+	}
+
+	if len(data) != 32 {
+		return fmt.Errorf("invalid key size")
+	}
+
+	copy((*key)[:], data[:32])
+
+	return nil
+}
+
+func (key *AES256Key) FromBase64(s string) error {
+	data, err := base64.StdEncoding.DecodeString(s)
+	if err != nil {
+		return err
+	}
+
+	if len(data) != 32 {
+		return fmt.Errorf("invalid key size")
+	}
+
+	copy((*key)[:], data[:32])
+
+	return nil
+}
+
+func (key *AES256Key) MarshalJSON() ([]byte, error) {
+	s := base64.StdEncoding.EncodeToString(key[:])
+	return json.Marshal(s)
+}
+
+func (pkey *AES256Key) UnmarshalJSON(data []byte) error {
+	var s string
+	if err := json.Unmarshal(data, &s); err != nil {
+		return err
+	}
+
+	key, err := base64.StdEncoding.DecodeString(s)
+	if err != nil {
+		return fmt.Errorf("cannot decode base64 value: %w", err)
+	}
+
+	if len(key) != 32 {
+		return fmt.Errorf("invalid key size (must be 32 bytes long)")
+	}
+
+	copy(pkey[:], key)
+
+	return nil
+}
+
+func (key *AES256Key) EncryptAES256(inputData []byte) ([]byte, error) {
+	blockCipher, err := aes.NewCipher(key[:])
+	if err != nil {
+		return nil, fmt.Errorf("cannot create cipher: %w", err)
+	}
+
+	paddedData := PadPKCS5(inputData, aes.BlockSize)
+
+	outputData := make([]byte, AES256IVSize+len(paddedData))
+
+	iv := outputData[:AES256IVSize]
+	encryptedData := outputData[AES256IVSize:]
+
+	if _, err := rand.Read(iv); err != nil {
+		return nil, fmt.Errorf("cannot generate iv: %w", err)
+	}
+
+	encrypter := cipher.NewCBCEncrypter(blockCipher, iv)
+	encrypter.CryptBlocks(encryptedData, paddedData)
+
+	return outputData, nil
+}
+
+func (key *AES256Key) DecryptAES256(inputData []byte) ([]byte, error) {
+	blockCipher, err := aes.NewCipher(key[:])
+	if err != nil {
+		return nil, fmt.Errorf("cannot create cipher: %w", err)
+	}
+
+	if len(inputData) < AES256IVSize {
+		return nil, fmt.Errorf("truncated data")
+	}
+
+	iv := inputData[:AES256IVSize]
+	paddedData := inputData[AES256IVSize:]
+
+	if len(paddedData)%aes.BlockSize != 0 {
+		return nil, fmt.Errorf("invalid padded data length")
+	}
+
+	decrypter := cipher.NewCBCDecrypter(blockCipher, iv)
+	decrypter.CryptBlocks(paddedData, paddedData)
+
+	outputData, err := UnpadPKCS5(paddedData, aes.BlockSize)
+	if err != nil {
+		return nil, fmt.Errorf("invalid padded data: %w", err)
+	}
+
+	return outputData, nil
+}
diff --git a/pkg/scrypto/aes256_test.go b/pkg/scrypto/aes256_test.go
new file mode 100644
index 0000000..9914625
--- /dev/null
+++ b/pkg/scrypto/aes256_test.go
@@ -0,0 +1,60 @@
+package scrypto
+
+import (
+	"encoding/hex"
+	"slices"
+	"strings"
+	"testing"
+)
+
+func TestAES256KeyHex(t *testing.T) {
+	testKeyHex := "28278b7c0a25f01d3cab639633b9487f9ea1e9a2176dc9595a3f01323aa44284"
+	testKey, _ := hex.DecodeString(testKeyHex)
+
+	var key AES256Key
+	if err := key.FromHex(testKeyHex); err != nil {
+		t.Errorf("got unexpected error %+v", err)
+	}
+	if slices.Compare(testKey, key[:]) != 0 {
+		t.Errorf("got %v, wanted %v", testKey, key[:])
+	}
+	if strings.Compare(testKeyHex, key.Hex()) != 0 {
+		t.Errorf("got %v, wanted %v", testKeyHex, key.Hex())
+	}
+}
+
+func TestAES256(t *testing.T) {
+	keyHex := "28278b7c0a25f01d3cab639633b9487f9ea1e9a2176dc9595a3f01323aa44284"
+	var key AES256Key
+	if err := key.FromHex(keyHex); err != nil {
+		t.Errorf("got unexpected error %+v", err)
+	}
+
+	data := []byte("Hello world!")
+	encryptedData, err := key.EncryptAES256(data)
+	if err != nil {
+		t.Errorf("got unexpected error when encrypting data %+v", err)
+	}
+
+	decryptedData, err := key.DecryptAES256(encryptedData)
+	if err != nil {
+		t.Errorf("got unexpected error when decrypting data %+v", err)
+	}
+
+	if slices.Compare(data, decryptedData) != 0 {
+		t.Errorf("got %v, wanted %v", decryptedData, data)
+	}
+}
+
+func TestAES256InvalidData(t *testing.T) {
+	keyHex := "28278b7c0a25f01d3cab639633b9487f9ea1e9a2176dc9595a3f01323aa44284"
+	var key AES256Key
+	if err := key.FromHex(keyHex); err != nil {
+		t.Errorf("got unexpected error when converting data from base64: %+v", err)
+	}
+
+	iv := make([]byte, AES256IVSize)
+	if _, err := key.DecryptAES256(append(iv, []byte("foo")...)); err == nil {
+		t.Error("decrypting operation should have failed")
+	}
+}
diff --git a/pkg/scrypto/pkcs5.go b/pkg/scrypto/pkcs5.go
new file mode 100644
index 0000000..b41c564
--- /dev/null
+++ b/pkg/scrypto/pkcs5.go
@@ -0,0 +1,31 @@
+package scrypto
+
+import (
+	"bytes"
+	"fmt"
+)
+
+func PadPKCS5(data []byte, blockSize int) []byte {
+	paddingSize := blockSize - len(data)%blockSize
+	padding := bytes.Repeat([]byte{byte(paddingSize)}, paddingSize)
+
+	return append(data, padding...)
+}
+
+func UnpadPKCS5(data []byte, blockSize int) ([]byte, error) {
+	dataSize := len(data)
+	if dataSize%blockSize != 0 {
+		return nil, fmt.Errorf("truncated data")
+	}
+
+	if len(data) == 0 {
+		return data, nil
+	} else {
+		paddingSize := int(data[dataSize-1])
+		if paddingSize > dataSize || paddingSize > blockSize {
+			return nil, fmt.Errorf("invalid padding size %d", paddingSize)
+		}
+
+		return data[:dataSize-paddingSize], nil
+	}
+}
diff --git a/pkg/scrypto/pkcs5_test.go b/pkg/scrypto/pkcs5_test.go
new file mode 100644
index 0000000..8bd1a1d
--- /dev/null
+++ b/pkg/scrypto/pkcs5_test.go
@@ -0,0 +1,52 @@
+package scrypto
+
+import (
+	"slices"
+	"testing"
+)
+
+func TestPadPKCS5(t *testing.T) {
+	tests := []struct {
+		data []byte
+		want []byte
+	}{
+		{data: []byte(""), want: []byte("\x04\x04\x04\x04")},
+		{data: []byte("a"), want: []byte("a\x03\x03\x03")},
+		{data: []byte("ab"), want: []byte("ab\x02\x02")},
+		{data: []byte("abc"), want: []byte("abc\x01")},
+		{data: []byte("abcd"), want: []byte("abcd\x04\x04\x04\x04")},
+		{data: []byte("abcde"), want: []byte("abcde\x03\x03\x03")},
+		{data: []byte("abcdefgh"), want: []byte("abcdefgh\x04\x04\x04\x04")},
+	}
+	for _, tt := range tests {
+		got := PadPKCS5(tt.data, 4)
+		if slices.Compare(got, tt.want) != 0 {
+			t.Errorf("got %v, want %v", got, tt.want)
+		}
+	}
+}
+
+func TestUnpadPKCS5(t *testing.T) {
+	tests := []struct {
+		data []byte
+		want []byte
+	}{
+		{data: []byte("\x04\x04\x04\x04"), want: []byte("")},
+		{data: []byte("a\x03\x03\x03"), want: []byte("a")},
+		{data: []byte("ab\x02\x02"), want: []byte("ab")},
+		{data: []byte("abc\x01"), want: []byte("abc")},
+		{data: []byte("abcd\x04\x04\x04\x04"), want: []byte("abcd")},
+		{data: []byte("abcde\x03\x03\x03"), want: []byte("abcde")},
+		{data: []byte("abcdefgh\x04\x04\x04\x04"), want: []byte("abcdefgh")},
+	}
+	for _, tt := range tests {
+		got, err := UnpadPKCS5(tt.data, 4)
+		if err != nil {
+			t.Errorf("got err %+v while wanted %v", err, tt.want)
+		} else {
+			if slices.Compare(got, tt.want) != 0 {
+				t.Errorf("got %v, want %v", got, tt.want)
+			}
+		}
+	}
+}
diff --git a/pkg/scrypto/random.go b/pkg/scrypto/random.go
new file mode 100644
index 0000000..47d9557
--- /dev/null
+++ b/pkg/scrypto/random.go
@@ -0,0 +1,16 @@
+package scrypto
+
+import (
+	"crypto/rand"
+	"fmt"
+)
+
+func RandomBytes(n int) []byte {
+	data := make([]byte, n)
+
+	if _, err := rand.Read(data); err != nil {
+		panic(fmt.Sprintf("cannot generate random data: %+v", err))
+	}
+
+	return data
+}