Phase 1 in progress

paccrypt_algos/aes_gcm.py

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+import os
+import base64
+import json
+from typing import Optional
+
+from cryptography.hazmat.primitives.kdf.pbkdf2 import PBKDF2HMAC
+from cryptography.hazmat.primitives.ciphers.aead import AESGCM
+from cryptography.hazmat.primitives import hashes
+from cryptography.hazmat.backends import default_backend
+
+# === Constants ===
+SALT_LENGTH = 16
+IV_LENGTH = 12
+PBKDF2_ITERATIONS = 200_000
+KEY_LENGTH = 32  # 256 bits
+
+# === Base64 Helpers ===
+def b64encode(data: bytes) -> str:
+    return base64.b64encode(data).decode('utf-8')
+
+def b64decode(data: str) -> bytes:
+    return base64.b64decode(data.encode('utf-8'))
+
+# === Key Derivation ===
+def derive_key(password: str, salt: bytes) -> bytes:
+    kdf = PBKDF2HMAC(
+        algorithm=hashes.SHA256(),
+        length=KEY_LENGTH,
+        salt=salt,
+        iterations=PBKDF2_ITERATIONS,
+        backend=default_backend()
+    )
+    return kdf.derive(password.encode('utf-8'))
+
+# === Encrypt Text ===
+def encrypt_text(plaintext: str, password: str) -> str:
+    salt = os.urandom(SALT_LENGTH)
+    iv = os.urandom(IV_LENGTH)
+    key = derive_key(password, salt)
+
+    aesgcm = AESGCM(key)
+    ciphertext = aesgcm.encrypt(iv, plaintext.encode('utf-8'), None)
+
+    payload = salt + iv + ciphertext
+    return b64encode(payload)
+
+# === Decrypt Text ===
+def decrypt_text(encrypted_b64: str, password: str) -> str:
+    raw = b64decode(encrypted_b64)
+    salt = raw[:SALT_LENGTH]
+    iv = raw[SALT_LENGTH:SALT_LENGTH + IV_LENGTH]
+    ciphertext = raw[SALT_LENGTH + IV_LENGTH:]
+
+    key = derive_key(password, salt)
+    aesgcm = AESGCM(key)
+    plaintext = aesgcm.decrypt(iv, ciphertext, None)
+    return plaintext.decode('utf-8')
+
+# === Metadata-less file interface (optional placeholders) ===
+def encrypt_file(in_path, out_path, key, metadata: Optional[dict] = None):
+    raise NotImplementedError("File encryption not implemented yet.")
+
+def decrypt_file(in_path, out_path, key, metadata: Optional[dict] = None):
+    raise NotImplementedError("File decryption not implemented yet.")
+
+# === Engine Name ===
+def get_name():
+    return "AES-GCM"