com.amazonaws.services.s3.package-info Maven / Gradle / Ivy
/*
* Copyright 2010-2017 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License").
* You may not use this file except in compliance with the License.
* A copy of the License is located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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.
*/
/**
* Synchronous client for accessing Amazon S3.
*
* Appendix: Amazon S3 client-side encryption meta information
*
* Introduction
*
* This appendix summarizes the current crypto related meta information
* associated with an S3 object encrypted using SDK client-side encryption. In
* SDK's terminology, these meta information are classified as "user metatdata".
* In general, the meta information is just a map of key/value pairs. Physically
* they are persisted either as metadata of the encrypted S3 object, or as a
* separate S3 object called an "instruction file" (which is just a JSON file in
* plaintext.) For all references to the Cipher Algorithm Names, Modes, and Padding,
* such as "AES/CBC/PKCS5Padding", please refer to Oracle's Java™ Cryptography Architecture Standard Algorithm Name Documentation
* for more details.
*
*
S3 metadata vs instruction file
*
* Note when a key/value pair is stored as "user metadata" as part of the S3
* metadata, the SDK always adds an additional prefix of x-amz-meta- to
* the key name. In contrast, the SDK doesn't add any prefix when the key names
* are stored in an instruction file. (The reason has to do with how the http
* headers are handled.)
*
* For example, x-amz-key would get stored as x-amz-meta-x-amz-key
* in S3 metadata. In contrast, x-amz-key would simply be stored as is
* (ie without the prefix) in an instruction file.
*
* All the keys described below are considered "user metadata" by the SDK.
*
*
S3 v1 crypto meta information (supported by all SDK's)
*
* For non-KMS client side encryption, this v1 crypto meta information is used
* to support the "Encryption Only" crypto mode (which involves the use of
* AES/CBC/PKCS5Padding for content encryption, and
* AES/ECB for encrypting the one-time randomly generated data
* key). For KMS client-side encryption, the v2 crypto meta information is used.
*
*
*
* key
* description
*
*
* x-amz-key
* Content encrypting key (cek) in encrypted form, base64 encoded. The cek
* is randomly generated per S3 object, and is always an AES 256-bit key. The
* corresponding cipher is always "AES/CBC/PKCS5Padding".
*
*
* x-amz-iv
* Randomly generated IV (per S3 object), base64 encoded
*
*
* x-amz-matdesc
* Customer provided material description in JSON (UTF8) format. Used to
* identify the client-side master key (ie used to encrypt/wrap the generated
* content encrypting key).
*
*
* x-amz-unencrypted-content-length
* Unencrypted content length (optional but should be specified whenever
* possible).
*
*
*
* S3 v2 crypto meta information (currently supported by the Java SDK)
*
* This v2 crypto meta information is used to support both authenticated
* encryption (which involves the use of AES/GCM/NoPadding for
* content encryption, and key wrapping for the one-time randomly generated data
* key), and KMS client-side encryption (which can either be encryption-only or
* authenticated encryption.)
*
*
*
* key
* description
*
*
* x-amz-key-v2
* CEK in key wrapped form. This is necessary so that the S3 encryption
* client that doesn't recognize the v2 format will not mistakenly decrypt S3
* object encrypted in v2 format.
*
*
* x-amz-iv
* Randomly generated IV (per S3 object), base64 encoded. (Same as v1.)
*
*
* x-amz-matdesc
* Customer provided material description in JSON format. (Same as v1). Used
* to identify the client-side master key.
*
* - For KMS client side encryption, the KMS Customer Master Key ID is stored
* as part of the material description, x-amz-matdesc, under the key-name
*
"kms_cmk_id".
*
*
*
*
* x-amz-unencrypted-content-length
* Unencrypted content length. (optional but should be specified whenever
* possible. Same as v1.)
*
*
* x-amz-wrap-alg
* Key wrapping algorithm used.
*
* - Supported values:
*
"AESWrap", "RSA/ECB/OAEPWithSHA-256AndMGF1Padding", "kms"
* - No standard key wrapping is used if this meta information is absent
* - Always set to "kms" if KMS is used for client-side encryption
*
*
*
*
* x-amz-cek-alg
* Content encryption algorithm used.
*
* - Supported values:
*
"AES/GCM/NoPadding", "AES/CBC/PKCS5Padding"
* - Default to
"AES/CBC/PKCS5Padding" if this key is absent.
*
*
*
*
* x-amz-tag-len
* Tag length (in bits) when AEAD is in use.
*
* - Only applicable if AEAD is in use. This meta information is absent
* otherwise, or if KMS is in use.
* - Supported value:
"128"
*
*
*
*
*
*
KMS Integration for client-side encryption
*
* - All client-side KMS protected S3 objects are stored in v2 crypto meta information
* format. However, the key wrapping algorithm, x-amz-wrap-alg is always
* set to "kms".
* - The KMS Customer Master Key ID is currently stored as part of the
* material description, x-amz-matdesc, under the key-name
* "kms_cmk_id".
*
*
*
Sample S3 crypto meta information for KMS client-side encryption
*
*
CryptoMode: Encryption Only
*
*
* x-amz-meta-x-amz-key-v2:
* CiAJ2GqwpJRnt4izujwoalC2YdNRNSMEslG5rw3pEI+J8hKnAQEBAwB4CdhqsKSUZ7eIs7o8KGpQtmHTUTUjBLJRua8N6RCPifIAAAB+MHwGCSqGSIb3DQEHBqBvMG0CAQAwaAYJKoZIhvcNAQcBMB4GCWCGSAFlAwQBLjARBAyD0rzN3KHViWixDVcCARCAOwhZ6xA8rob3Z0mNx3uKFieHKVyIC/PKlchALvG1oVLnf86mcZJNpTXtwMkKkDocVj3Z1zGjZTufFsOH
* x-amz-iv: xqOHh+M6y0UogwG5SHJM3Q==
* x-amz-unencrypted-content-length: 32768
* x-amz-cek-alg: AES/CBC/PKCS5Padding
* x-amz-wrap-alg: kms
* x-amz-matdesc: {"kms_cmk_id":"d3fd2273-4ca0-4da5-b1c2-c89742ec6a26"}
*
*
* CryptoMode: Authenticated Encryption
*
*
* x-amz-key-v2: CiAJ2GqwpJRnt4izujwoalC2YdNRNSMEslG5rw3pEI+J8hKnAQEBAwB4CdhqsKSUZ7eIs7o8KGpQtmHTUTUjBLJRua8N6RCPifIAAAB+MHwGCSqGSIb3DQEHBqBvMG0CAQAwaAYJKoZIhvcNAQcBMB4GCWCGSAFlAwQBLjARBAytFVyW4I6QmwcPK1ECARCAO1VzoM6KxA9DHyNMm/BEbbjle2vLA7IY7f9OkUoSqrdxgKxpNID9QaL/7928m1Djtld0bJpHefjm89C
* x-amz-iv: VZBksyij6DhrUMye
* x-amz-unencrypted-content-length: 32768
* x-amz-cek-alg: AES/GCM/NoPadding
* x-amz-wrap-alg: kms
* x-amz-matdesc: {"kms_cmk_id":"d3fd2273-4ca0-4da5-b1c2-c89742ec6a26"}
* x-amz-tag-len: 128
*
*
* S3 metadata of an instruction file
*
* The following key is always included as part of the S3 metadata of the
* instruction file (which is just an S3 object). Since the SDK treats this key
* as "user metadata", the key name is always prefixed with x-amz-meta-
* when physically stored.
*
*
*
* key
* description
*
*
* x-amz-crypto-instr-file
* the presence of this key is used to indicate this S3 object is an
* instruction file (of an associated client-side encrypted S3 object).
*
*
*/
package com.amazonaws.services.s3;