go-crypt/crypt/symmetric.go
Claude 8498ecf890
feat: extract crypto/security packages from core/go
ChaCha20-Poly1305, AES-256-GCM, Argon2 key derivation, OpenPGP
challenge-response auth, and trust tier policy engine.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
2026-02-16 15:25:54 +00:00

100 lines
3 KiB
Go

package crypt
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
core "forge.lthn.ai/core/go/pkg/framework/core"
"golang.org/x/crypto/chacha20poly1305"
)
// ChaCha20Encrypt encrypts plaintext using ChaCha20-Poly1305.
// The key must be 32 bytes. The nonce is randomly generated and prepended
// to the ciphertext.
func ChaCha20Encrypt(plaintext, key []byte) ([]byte, error) {
aead, err := chacha20poly1305.NewX(key)
if err != nil {
return nil, core.E("crypt.ChaCha20Encrypt", "failed to create cipher", err)
}
nonce := make([]byte, aead.NonceSize())
if _, err := rand.Read(nonce); err != nil {
return nil, core.E("crypt.ChaCha20Encrypt", "failed to generate nonce", err)
}
ciphertext := aead.Seal(nonce, nonce, plaintext, nil)
return ciphertext, nil
}
// ChaCha20Decrypt decrypts ciphertext encrypted with ChaCha20Encrypt.
// The key must be 32 bytes. Expects the nonce prepended to the ciphertext.
func ChaCha20Decrypt(ciphertext, key []byte) ([]byte, error) {
aead, err := chacha20poly1305.NewX(key)
if err != nil {
return nil, core.E("crypt.ChaCha20Decrypt", "failed to create cipher", err)
}
nonceSize := aead.NonceSize()
if len(ciphertext) < nonceSize {
return nil, core.E("crypt.ChaCha20Decrypt", "ciphertext too short", nil)
}
nonce, encrypted := ciphertext[:nonceSize], ciphertext[nonceSize:]
plaintext, err := aead.Open(nil, nonce, encrypted, nil)
if err != nil {
return nil, core.E("crypt.ChaCha20Decrypt", "failed to decrypt", err)
}
return plaintext, nil
}
// AESGCMEncrypt encrypts plaintext using AES-256-GCM.
// The key must be 32 bytes. The nonce is randomly generated and prepended
// to the ciphertext.
func AESGCMEncrypt(plaintext, key []byte) ([]byte, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, core.E("crypt.AESGCMEncrypt", "failed to create cipher", err)
}
aead, err := cipher.NewGCM(block)
if err != nil {
return nil, core.E("crypt.AESGCMEncrypt", "failed to create GCM", err)
}
nonce := make([]byte, aead.NonceSize())
if _, err := rand.Read(nonce); err != nil {
return nil, core.E("crypt.AESGCMEncrypt", "failed to generate nonce", err)
}
ciphertext := aead.Seal(nonce, nonce, plaintext, nil)
return ciphertext, nil
}
// AESGCMDecrypt decrypts ciphertext encrypted with AESGCMEncrypt.
// The key must be 32 bytes. Expects the nonce prepended to the ciphertext.
func AESGCMDecrypt(ciphertext, key []byte) ([]byte, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, core.E("crypt.AESGCMDecrypt", "failed to create cipher", err)
}
aead, err := cipher.NewGCM(block)
if err != nil {
return nil, core.E("crypt.AESGCMDecrypt", "failed to create GCM", err)
}
nonceSize := aead.NonceSize()
if len(ciphertext) < nonceSize {
return nil, core.E("crypt.AESGCMDecrypt", "ciphertext too short", nil)
}
nonce, encrypted := ciphertext[:nonceSize], ciphertext[nonceSize:]
plaintext, err := aead.Open(nil, nonce, encrypted, nil)
if err != nil {
return nil, core.E("crypt.AESGCMDecrypt", "failed to decrypt", err)
}
return plaintext, nil
}