xanderbailey commented on code in PR #2026: URL: https://github.com/apache/iceberg-rust/pull/2026#discussion_r2929821042
########## crates/iceberg/src/encryption/crypto.rs: ########## @@ -0,0 +1,458 @@ +// Licensed to the Apache Software Foundation (ASF) under one +// or more contributor license agreements. See the NOTICE file +// distributed with this work for additional information +// regarding copyright ownership. The ASF licenses this file +// to you under the Apache License, Version 2.0 (the +// "License"); you may not use this file except in compliance +// with the License. You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, +// software distributed under the License is distributed on an +// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +// KIND, either express or implied. See the License for the +// specific language governing permissions and limitations +// under the License. + +//! Core cryptographic operations for Iceberg encryption. + +use std::fmt; +use std::str::FromStr; + +use aes_gcm::aead::generic_array::typenum::Unsigned; +use aes_gcm::aead::rand_core::RngCore; +use aes_gcm::aead::{Aead, AeadCore, KeyInit, KeySizeUser, OsRng, Payload}; +use aes_gcm::{Aes128Gcm, Key, Nonce}; +use zeroize::Zeroizing; + +use crate::{Error, ErrorKind, Result}; + +/// Wrapper for sensitive byte data (encryption keys, DEKs, etc.) that: +/// - Zeroizes memory on drop +/// - Redacts content in [`Debug`] output +/// - Provides only `&[u8]` access via [`as_bytes()`](Self::as_bytes) +/// - Uses `Box<[u8]>` (immutable boxed slice) since key bytes never grow +/// +/// Use this type for any struct field that holds plaintext key material. +/// Because its [`Debug`] impl always prints `[N bytes REDACTED]`, structs +/// containing `SensitiveBytes` can safely derive or implement `Debug` +/// without risk of leaking key material. +#[derive(Clone, PartialEq, Eq)] +pub struct SensitiveBytes(Zeroizing<Box<[u8]>>); + +impl SensitiveBytes { + /// Wraps the given bytes as sensitive material. + pub fn new(bytes: impl Into<Box<[u8]>>) -> Self { + Self(Zeroizing::new(bytes.into())) + } + + /// Returns the underlying bytes. + pub fn as_bytes(&self) -> &[u8] { + &self.0 + } + + /// Returns the number of bytes. + pub fn len(&self) -> usize { + self.0.len() + } + + /// Returns `true` if the byte slice is empty. + pub fn is_empty(&self) -> bool { + self.0.is_empty() + } +} + +impl fmt::Debug for SensitiveBytes { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "[{} bytes REDACTED]", self.0.len()) + } +} + +/// Supported encryption algorithm. +/// Currently only AES-128-GCM is supported as it's the only algorithm +/// compatible with arrow-rs Parquet encryption. +#[derive(Debug, Clone, Copy, PartialEq, Eq)] +pub enum EncryptionAlgorithm { + /// AES-128 in GCM mode + Aes128Gcm, +} + +impl EncryptionAlgorithm { + /// Returns the key length in bytes for this algorithm. + pub fn key_length(&self) -> usize { + match self { + Self::Aes128Gcm => <Aes128Gcm as KeySizeUser>::KeySize::USIZE, + } + } + + /// Returns the nonce/IV length in bytes for this algorithm. + pub fn nonce_length(&self) -> usize { + match self { + Self::Aes128Gcm => <Aes128Gcm as AeadCore>::NonceSize::USIZE, + } + } + + /// Returns the string identifier for this algorithm. + pub fn as_str(&self) -> &'static str { + match self { + Self::Aes128Gcm => "AES_GCM_128", + } + } + + /// Returns the algorithm for a given DEK length in bytes. + /// + /// Matches Java's `encryption.data-key-length` property semantics: + /// 16 → AES-128-GCM. + pub fn from_key_length(len: usize) -> Result<Self> { + match len { + 16 => Ok(Self::Aes128Gcm), + _ => Err(Error::new( + ErrorKind::DataInvalid, + format!("Unsupported data key length: {len} (must be 16)"), + )), + } + } +} + +impl FromStr for EncryptionAlgorithm { + type Err = Error; + + fn from_str(s: &str) -> Result<Self> { + match s { + "AES_GCM_128" | "AES128_GCM" => Ok(Self::Aes128Gcm), + _ => Err(Error::new( + ErrorKind::DataInvalid, + format!("Unsupported encryption algorithm: {s}"), + )), + } + } +} + +/// A secure encryption key that zeroes its memory on drop. +pub struct SecureKey { + key: SensitiveBytes, + algorithm: EncryptionAlgorithm, +} + +impl SecureKey { + /// Creates a new secure key with the specified algorithm. + /// + /// # Errors + /// Returns an error if the key length doesn't match the algorithm requirements. + pub fn new(key: &[u8], algorithm: EncryptionAlgorithm) -> Result<Self> { + if key.len() != algorithm.key_length() { + return Err(Error::new( + ErrorKind::DataInvalid, + format!( + "Invalid key length for {:?}: expected {} bytes, got {}", + algorithm, + algorithm.key_length(), + key.len() + ), + )); + } + Ok(Self { + key: SensitiveBytes::new(key), + algorithm, + }) + } + + /// Generates a new random key for the specified algorithm. + pub fn generate(algorithm: EncryptionAlgorithm) -> Self { + let mut key = vec![0u8; algorithm.key_length()]; + OsRng.fill_bytes(&mut key); + Self { + key: SensitiveBytes::new(key), + algorithm, + } + } + + /// Returns the encryption algorithm for this key. + pub fn algorithm(&self) -> EncryptionAlgorithm { + self.algorithm + } + + /// Returns the key bytes. + pub fn as_bytes(&self) -> &[u8] { + &self.key.as_bytes() + } +} + +enum CipherImpl { + Aes128Gcm(Aes128Gcm), +} + +/// AES-GCM encryptor for encrypting and decrypting data. +/// +/// The cipher is initialized once at construction time. +pub struct AesGcmEncryptor { + cipher: CipherImpl, Review Comment: Yes, the additional option is to use 256 which is still AES-GCM but different length keys. -- This is an automated message from the Apache Git Service. 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