From e7886a26fb48c1a4755db902c83e878b113a568d Mon Sep 17 00:00:00 2001
From: The-Tysonator <ring.oaks_0v@icloud.com>
Date: Thu, 12 Oct 2023 11:11:16 +0100
Subject: [PATCH] Added the ARGON2 algorithm.

---
 README.md                      |  1 +
 algorithms/argon2/Algorithm.go | 22 +++++++++++++
 algorithms/argon2/CheckHash.go | 58 ++++++++++++++++++++++++++++++++++
 algorithms/argon2/Hash.go      | 24 ++++++++++++++
 4 files changed, 105 insertions(+)
 create mode 100644 algorithms/argon2/Algorithm.go
 create mode 100644 algorithms/argon2/CheckHash.go
 create mode 100644 algorithms/argon2/Hash.go

diff --git a/README.md b/README.md
index fb6a1da..29f0d4b 100644
--- a/README.md
+++ b/README.md
@@ -13,6 +13,7 @@ GCL is a Go library designed to offer a robust collection of cryptographic algor
 
 GCL offers support for a diverse range of cryptographic algorithms, ensuring that your cryptographic requirements are comprehensively addressed. Our library includes:
 
+- [X] ARGON2
 - [X] BLAKE2
 - [X] SHA256
 - [X] SHA512
diff --git a/algorithms/argon2/Algorithm.go b/algorithms/argon2/Algorithm.go
new file mode 100644
index 0000000..d1149c1
--- /dev/null
+++ b/algorithms/argon2/Algorithm.go
@@ -0,0 +1,22 @@
+package argon2
+
+// Algorithm
+type Algorithm struct {
+	keyLen  uint32
+	memory  uint32
+	saltLen uint32
+	threads uint8
+	time    uint32
+}
+
+// New
+func New(keyLen uint32, memory uint32, saltLen uint32, threads uint8, time uint32) Algorithm {
+	// Return Algorithm
+	return Algorithm{
+		keyLen:  keyLen,
+		memory:  memory,
+		saltLen: saltLen,
+		threads: threads,
+		time:    time,
+	}
+}
diff --git a/algorithms/argon2/CheckHash.go b/algorithms/argon2/CheckHash.go
new file mode 100644
index 0000000..5920232
--- /dev/null
+++ b/algorithms/argon2/CheckHash.go
@@ -0,0 +1,58 @@
+package argon2
+
+import (
+	// Standard
+	"crypto/subtle"
+	"encoding/base64"
+	"errors"
+	"fmt"
+	"strings"
+
+	// Standard Extended
+	"golang.org/x/crypto/argon2"
+)
+
+// Check Hash
+func (algorithm Algorithm) CheckHash(data []byte, hashToCheck string) (bool, error) {
+	// Hash Information
+	var version int
+	var memory uint32
+	var threads uint8
+	var time uint32
+	// Hash Parts
+	hashParts := strings.Split(hashToCheck, "$")
+	// Validate Hash Parts
+	if len(hashParts) != 6 {
+		return false, errors.New("the hash is invalid")
+	}
+	// Get Version
+	_, err := fmt.Sscanf(hashParts[2], "v=%d", &version)
+	// Handle Error
+	if err != nil {
+		return false, err
+	}
+	// Validate Version
+	if version != argon2.Version {
+		return false, errors.New("incompatible version")
+	}
+	// Get Other Hash Information
+	_, err = fmt.Sscanf(hashParts[3], "m=%d,t=%d,p=%d", &memory, &time, &threads)
+	// Handle Error
+	if err != nil {
+		return false, err
+	}
+	// Salt
+	salt, err := base64.RawStdEncoding.Strict().DecodeString(hashParts[4])
+	// Handle Error
+	if err != nil {
+		return false, err
+	}
+	// Hash
+	hash, err := base64.RawStdEncoding.Strict().DecodeString(hashParts[5])
+	// Handle Error
+	if err != nil {
+		return false, err
+	}
+	// Return Match
+	return subtle.ConstantTimeCompare(argon2.IDKey(data, salt, time, memory, threads, uint32(len(hash))), hash) == 1, err
+}
diff --git a/algorithms/argon2/Hash.go b/algorithms/argon2/Hash.go
new file mode 100644
index 0000000..d77f768
--- /dev/null
+++ b/algorithms/argon2/Hash.go
@@ -0,0 +1,24 @@
+package argon2
+
+import (
+	// Standard
+	"crypto/rand"
+	"encoding/base64"
+	"fmt"
+
+	// Standard Extended
+	"golang.org/x/crypto/argon2"
+)
+
+// Hash
+func (algorithm Algorithm) Hash(data []byte) (string, error) {
+	// Generate Salt
+	salt := make([]byte, algorithm.saltLen)
+	_, err := rand.Read(salt)
+	// Handle Error
+	if err != nil {
+		return "", err
+	}
+	// Hash
+	return fmt.Sprintf("$argon2id$v=%d$m=%d,t=%d,p=%d$%s$%s", argon2.Version, algorithm.memory, algorithm.time, algorithm.threads, base64.RawStdEncoding.EncodeToString(salt), base64.RawStdEncoding.EncodeToString(argon2.IDKey(data, salt, algorithm.time, algorithm.memory, algorithm.threads, algorithm.keyLen))), err
+}