com.qcloud.cos.internal.crypto.ContentCryptoMaterial Maven / Gradle / Ivy
Show all versions of cos_api-bundle Show documentation
/*
* Copyright 2010-2019 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.
* According to cos feature, we modify some class，comment, field name, etc.
*/
package com.qcloud.cos.internal.crypto;
import static com.qcloud.cos.internal.crypto.KMSSecuredCEK.isKMSKeyWrapped;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.nio.charset.Charset;
import java.security.Key;
import java.security.Provider;
import java.security.SecureRandom;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
import java.util.TreeMap;
import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.qcloud.cos.Headers;
import com.qcloud.cos.exception.CosClientException;
import com.qcloud.cos.internal.CosServiceRequest;
import com.qcloud.cos.model.COSObject;
import com.qcloud.cos.model.MaterialsDescriptionProvider;
import com.qcloud.cos.model.ObjectMetadata;
import com.qcloud.cos.utils.Base64;
import com.qcloud.cos.utils.Jackson;
import com.qcloud.cos.utils.StringUtils;
import com.tencentcloudapi.kms.v20190118.models.DecryptRequest;
import com.tencentcloudapi.kms.v20190118.models.DecryptResponse;
import com.tencentcloudapi.kms.v20190118.models.EncryptRequest;
import com.tencentcloudapi.kms.v20190118.models.EncryptResponse;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* Cryptographic material used for client-side content encrypt/decryption in COS. This includes the
* randomly generated one-time secured CEK (content-encryption-key) and the respective key wrapping
* algorithm, if any, and the cryptographic scheme in use.
*/
final class ContentCryptoMaterial {
// null if cek is not secured via key wrapping
private final String keyWrappingAlgorithm;
private final CipherLite cipherLite;
private final Map kekMaterialsDescription;
private final byte[] encryptedCEK;
private final byte[] securedIV;
private static final Logger log = LoggerFactory.getLogger(ContentCryptoMaterial.class);
ContentCryptoMaterial(Map kekMaterialsDescription, byte[] encryptedCEK,
String keyWrappingAlgorithm, CipherLite cipherLite, byte[] securedIV) {
this.cipherLite = cipherLite;
this.keyWrappingAlgorithm = keyWrappingAlgorithm;
this.encryptedCEK = encryptedCEK.clone();
this.kekMaterialsDescription = kekMaterialsDescription;
this.securedIV = securedIV;
}
/**
* Returns the key wrapping algorithm, or null if the content key is not secured via a key
* wrapping algorithm.
*
* Note if the returned value is {@value KMSSecuredCEK#KEY_PROTECTION_MECHANISM}, it means the
* key is protected via KMS rather than a direct key-wrapping algorithm.
*/
String getKeyWrappingAlgorithm() {
return keyWrappingAlgorithm;
}
/**
* Returns true if KMS is used for the content key protection; false otherwise.
*/
private boolean usesKMSKey() {
return isKMSKeyWrapped(keyWrappingAlgorithm);
}
/**
* Returns the content crypto scheme.
*/
ContentCryptoScheme getContentCryptoScheme() {
return cipherLite.getContentCryptoScheme();
}
/**
* Returns the given metadata updated with this content crypto material.
*/
ObjectMetadata toObjectMetadata(ObjectMetadata metadata, CryptoMode mode) {
return toObjectMetadata(metadata);
}
/**
* Returns the metadata in the latest format.
*/
private ObjectMetadata toObjectMetadata(ObjectMetadata metadata) {
// If we generated a symmetric key to encrypt the data, store it in the
// object metadata.
byte[] encryptedCEK = getEncryptedCEK();
metadata.addUserMetadata(Headers.ENCRYPTION_KEY, Base64.encodeAsString(encryptedCEK));
// Put the cipher initialization vector (IV) into the object metadata
metadata.addUserMetadata(Headers.ENCRYPTION_START, Base64.encodeAsString(securedIV));
// Put the materials description into the object metadata as JSON
String matdesc = kekMaterialDescAsJson();
if (matdesc != null) {
metadata.addUserMetadata(Headers.ENCRYPTION_MATDESC, kekMaterialDescAsJson());
}
// The CRYPTO_CEK_ALGORITHM, CRYPTO_TAG_LENGTH and
// CRYPTO_KEYWRAP_ALGORITHM were not available in the Encryption Only
// (EO) implementation
ContentCryptoScheme scheme = getContentCryptoScheme();
metadata.addUserMetadata(Headers.ENCRYPTION_CEK_ALG, scheme.getCipherAlgorithm());
int tagLen = scheme.getTagLengthInBits();
if (tagLen > 0)
metadata.addUserMetadata(Headers.CRYPTO_TAG_LENGTH, String.valueOf(tagLen));
String keyWrapAlgo = getKeyWrappingAlgorithm();
if (keyWrapAlgo != null)
metadata.addUserMetadata(Headers.ENCRYPTION_WRAP_ALG, keyWrapAlgo);
return metadata;
}
/**
* Returns the json string in the latest format.
*/
String toJsonString() {
Map map = new HashMap();
byte[] encryptedCEK = getEncryptedCEK();
map.put(Headers.CRYPTO_KEY_V2, Base64.encodeAsString(encryptedCEK));
byte[] iv = cipherLite.getIV();
map.put(Headers.CRYPTO_IV, Base64.encodeAsString(iv));
map.put(Headers.MATERIALS_DESCRIPTION, kekMaterialDescAsJson());
ContentCryptoScheme scheme = getContentCryptoScheme();
map.put(Headers.CRYPTO_CEK_ALGORITHM, scheme.getCipherAlgorithm());
int tagLen = scheme.getTagLengthInBits();
if (tagLen > 0)
map.put(Headers.CRYPTO_TAG_LENGTH, String.valueOf(tagLen));
String keyWrapAlgo = getKeyWrappingAlgorithm();
if (keyWrapAlgo != null)
map.put(Headers.CRYPTO_KEYWRAP_ALGORITHM, keyWrapAlgo);
return Jackson.toJsonString(map);
}
/**
* Returns the key-encrypting-key material description as a non-null json string;
*/
private String kekMaterialDescAsJson() {
Map kekMaterialDesc = getKEKMaterialsDescription();
if (kekMaterialDesc == null || kekMaterialDesc.isEmpty())
return null;
return Jackson.toJsonString(kekMaterialDesc);
}
/**
* Returns the corresponding kek material description from the given json; or null if the input
* is null.
*/
@SuppressWarnings("unchecked")
private static Map matdescFromJson(String json) {
Map map = Jackson.fromJsonString(json, Map.class);
return map == null ? null : Collections.unmodifiableMap(map);
}
/**
* Returns the content encrypting key unwrapped or decrypted. Note if KMS is used for key
* protection, a remote call will be made to KMS to decrypt the ciphertext blob.
*
* @param cekSecured the content encrypting key in wrapped or encrypted form; must not be null
* @param keyWrapAlgo key wrapping algorithm; or null if direct encryption instead of key
* wrapping is used
* @param materials the client key encrypting key material for the content encrypting key
* @param securityProvider security provider or null if the default security provider of the JCE
* is used
*/
private static SecretKey cek(byte[] cekSecured, String keyWrapAlgo,
EncryptionMaterials materials, Provider securityProvider,
ContentCryptoScheme contentCryptoScheme, QCLOUDKMS kms) {
if (isKMSKeyWrapped(keyWrapAlgo))
return cekByKMS(cekSecured, keyWrapAlgo, materials, contentCryptoScheme, kms);
Key kek;
if (materials.getKeyPair() != null) {
// Do envelope decryption with private key from key pair
kek = materials.getKeyPair().getPrivate();
if (kek == null) {
throw new CosClientException("Key encrypting key not available");
}
} else {
// Do envelope decryption with symmetric key
kek = materials.getSymmetricKey();
if (kek == null) {
throw new CosClientException("Key encrypting key not available");
}
}
try {
if (keyWrapAlgo != null) {
// Key wrapping specified
Cipher cipher = securityProvider == null ? Cipher.getInstance(keyWrapAlgo)
: Cipher.getInstance(keyWrapAlgo, securityProvider);
cipher.init(Cipher.UNWRAP_MODE, kek);
return (SecretKey) cipher.unwrap(cekSecured, keyWrapAlgo, Cipher.SECRET_KEY);
}
// fall back to the Encryption Only (EO) key decrypting method
Cipher cipher;
if (securityProvider != null) {
cipher = Cipher.getInstance(kek.getAlgorithm(), securityProvider);
} else {
cipher = Cipher.getInstance(kek.getAlgorithm());
}
cipher.init(Cipher.DECRYPT_MODE, kek);
byte[] decryptedSymmetricKeyBytes = cipher.doFinal(cekSecured);
return new SecretKeySpec(decryptedSymmetricKeyBytes,
JceEncryptionConstants.SYMMETRIC_KEY_ALGORITHM);
} catch (Exception e) {
throw new CosClientException("Unable to decrypt symmetric key from object metadata", e);
}
}
/**
* Decrypts the secured CEK via KMS; involves network calls.
*
* @return the CEK (in plaintext).
*/
private static SecretKey cekByKMS(byte[] cekSecured, String keyWrapAlgo,
EncryptionMaterials materials, ContentCryptoScheme contentCryptoScheme, QCLOUDKMS kms) {
DecryptRequest decryptReq = new DecryptRequest();
Map materialDesc = materials.getMaterialsDescription();
try {
ObjectMapper mapper = new ObjectMapper();
decryptReq.setEncryptionContext(mapper.writeValueAsString(materialDesc));
} catch (JsonProcessingException e) {
throw new CosClientException("decrypt request set encryption context got json processing exception", e);
}
decryptReq.setCiphertextBlob(new String(cekSecured));
DecryptResponse decryptRes = kms.decrypt(decryptReq);
byte[] key = Base64.decode(decryptRes.getPlaintext());
return new SecretKeySpec(key, contentCryptoScheme.getKeyGeneratorAlgorithm());
}
/**
* @return a non-null content crypto material.
*/
static ContentCryptoMaterial fromObjectMetadata(ObjectMetadata metadata,
EncryptionMaterialsAccessor kekMaterialAccessor, Provider securityProvider,
boolean keyWrapExpected, QCLOUDKMS kms) {
return fromObjectMetadata0(metadata, kekMaterialAccessor, securityProvider, null,
keyWrapExpected, kms);
}
/**
* Factory method to return the content crypto material from the COS object meta data, using the
* specified key encrypting key material accessor and an optional security provider.
*
* @return a non-null content crypto material.
*/
static ContentCryptoMaterial fromObjectMetadata(ObjectMetadata metadata,
EncryptionMaterialsAccessor kekMaterialAccessor, Provider securityProvider,
long[] range, boolean keyWrapExpected, QCLOUDKMS kms) {
return fromObjectMetadata0(metadata, kekMaterialAccessor, securityProvider, range,
keyWrapExpected, kms);
}
/**
* @return a non-null content crypto material.
*/
private static ContentCryptoMaterial fromObjectMetadata0(ObjectMetadata metadata,
EncryptionMaterialsAccessor kekMaterialAccessor, Provider securityProvider,
long[] range, boolean keyWrapExpected, QCLOUDKMS kms) {
// CEK and IV
Map userMeta = metadata.getUserMetadata();
// new version has different header
if (userMeta.get(Headers.ENCRYPTION_KEY) != null) {
return fromObjectMetadata1(userMeta, kekMaterialAccessor, securityProvider,
range, keyWrapExpected, kms);
}
String b64key = userMeta.get(Headers.CRYPTO_KEY_V2);
if (b64key == null) {
b64key = userMeta.get(Headers.CRYPTO_KEY);
if (b64key == null)
throw new CosClientException("Content encrypting key not found.");
}
byte[] cekWrapped = Base64.decode(b64key);
//byte[] iv = userMeta.get(Headers.CRYPTO_IV).getBytes();
byte[] iv = Base64.decode(userMeta.get(Headers.CRYPTO_IV));
if (cekWrapped == null || iv == null) {
throw new CosClientException("Content encrypting key or IV not found.");
}
// Material description
String matdescStr = userMeta.get(Headers.MATERIALS_DESCRIPTION);
final String keyWrapAlgo = userMeta.get(Headers.CRYPTO_KEYWRAP_ALGORITHM);
final boolean isKMS = isKMSKeyWrapped(keyWrapAlgo);
final Map core = matdescFromJson(matdescStr);
final EncryptionMaterials materials;
if (isKMS) {
materials = new KMSEncryptionMaterials(
core.get(KMSEncryptionMaterials.CUSTOMER_MASTER_KEY_ID));
materials.addDescriptions(core);
} else {
materials = kekMaterialAccessor == null ? null
: kekMaterialAccessor.getEncryptionMaterials(core);
if (materials == null) {
throw new CosClientException("Unable to retrieve the client encryption materials");
}
}
// CEK algorithm
String cekAlgo = userMeta.get(Headers.CRYPTO_CEK_ALGORITHM);
boolean isRangeGet = range != null;
// The content crypto scheme may vary depending on whether
// it is a range get operation
ContentCryptoScheme contentCryptoScheme =
ContentCryptoScheme.fromCEKAlgo(cekAlgo, isRangeGet);
if (isRangeGet) {
// Adjust the IV as needed
iv = contentCryptoScheme.adjustIV(iv, range[0]);
} else {
// Validate the tag length supported
int tagLenExpected = contentCryptoScheme.getTagLengthInBits();
if (tagLenExpected > 0) {
String s = userMeta.get(Headers.CRYPTO_TAG_LENGTH);
int tagLenActual = Integer.parseInt(s);
if (tagLenExpected != tagLenActual) {
throw new CosClientException("Unsupported tag length: " + tagLenActual
+ ", expected: " + tagLenExpected);
}
}
}
// Unwrap or decrypt the CEK
if (keyWrapExpected && keyWrapAlgo == null)
throw newKeyWrapException();
SecretKey cek =
cek(cekWrapped, keyWrapAlgo, materials, securityProvider, contentCryptoScheme, kms);
return new ContentCryptoMaterial(core, cekWrapped, keyWrapAlgo, contentCryptoScheme
.createCipherLite(cek, iv, Cipher.DECRYPT_MODE, securityProvider), null);
}
private static ContentCryptoMaterial fromObjectMetadata1(Map userMeta,
EncryptionMaterialsAccessor kekMaterialAccessor, Provider securityProvider,
long[] range, boolean keyWrapExpected, QCLOUDKMS kms) {
String b64SecuredKey = userMeta.get(Headers.ENCRYPTION_KEY);
if (b64SecuredKey == null) {
throw new CosClientException("Content encrypting key not found.");
}
byte[] securedKey = Base64.decode(b64SecuredKey);
String b64SecuredIV = userMeta.get(Headers.ENCRYPTION_START);
if (b64SecuredIV == null) {
throw new CosClientException("Content encrypting key or IV not found.");
}
byte[] securedIV = Base64.decode(b64SecuredIV);
final String keyWrapAlgo = userMeta.get(Headers.ENCRYPTION_WRAP_ALG);
final String matdescStr = userMeta.get(Headers.ENCRYPTION_MATDESC);
final boolean isKMS = isKMSKeyWrapped(keyWrapAlgo);
final Map metadesc = matdescFromJson(matdescStr);
final EncryptionMaterials materials;
if (isKMS) {
if (kekMaterialAccessor instanceof KMSEncryptionMaterialsProvider) {
KMSEncryptionMaterialsProvider kmsMaterialsProvider = (KMSEncryptionMaterialsProvider) kekMaterialAccessor;
materials = kmsMaterialsProvider.getEncryptionMaterials();
} else {
throw new CosClientException("Must use KMSEncryptionMaterials");
}
if (metadesc != null) {
materials.addDescriptions(metadesc);
}
} else {
materials = kekMaterialAccessor == null ? null
: kekMaterialAccessor.getEncryptionMaterials(metadesc);
if (materials == null) {
throw new CosClientException("Unable to retrieve the client encryption materials");
}
}
// CEK algorithm
String cekAlgo = userMeta.get(Headers.ENCRYPTION_CEK_ALG);
boolean isRangeGet = range != null;
// The content crypto scheme may vary depending on whether
// it is a range get operation
ContentCryptoScheme contentCryptoScheme =
ContentCryptoScheme.fromCEKAlgo(cekAlgo, isRangeGet);
byte[] iv = decryptIV(securedIV, keyWrapAlgo, materials, securityProvider, contentCryptoScheme, kms);
if (isRangeGet) {
// Adjust the IV as needed
iv = contentCryptoScheme.adjustIV(iv, range[0]);
}
// Unwrap or decrypt the CEK
if (keyWrapExpected && keyWrapAlgo == null)
throw newKeyWrapException();
SecretKey cek =
cek(securedKey, keyWrapAlgo, materials, securityProvider, contentCryptoScheme, kms);
return new ContentCryptoMaterial(metadesc, securedKey, keyWrapAlgo, contentCryptoScheme
.createCipherLite(cek, iv, Cipher.DECRYPT_MODE, securityProvider), null);
}
private static CosClientException newKeyWrapException() {
return new CosClientException("Missing key-wrap for the content-encrypting-key");
}
/**
* @return a non-null content crypto material.
*/
static ContentCryptoMaterial fromInstructionFile(Map instFile,
EncryptionMaterialsAccessor kekMaterialAccessor, Provider securityProvider,
boolean keyWrapExpected, QCLOUDKMS kms) {
return fromInstructionFile0(instFile, kekMaterialAccessor, securityProvider, null,
keyWrapExpected, kms);
}
/**
* Factory method to return the content crypto material from the cos instruction file, using the
* specified key encrypting key material accessor and an optional security provider.
*
* @return a non-null content crypto material.
*/
static ContentCryptoMaterial fromInstructionFile(Map instFile,
EncryptionMaterialsAccessor kekMaterialAccessor, Provider securityProvider,
long[] range, boolean keyWrapExpected, QCLOUDKMS kms) {
return fromInstructionFile0(instFile, kekMaterialAccessor, securityProvider, range,
keyWrapExpected, kms);
}
/**
* @return a non-null content crypto material.
*/
private static ContentCryptoMaterial fromInstructionFile0(Map instFile,
EncryptionMaterialsAccessor kekMaterialAccessor, Provider securityProvider,
long[] range, boolean keyWrapExpected, QCLOUDKMS kms) {
// CEK and IV
String b64key = instFile.get(Headers.CRYPTO_KEY_V2);
if (b64key == null) {
b64key = instFile.get(Headers.CRYPTO_KEY);
if (b64key == null)
throw new CosClientException("Content encrypting key not found.");
}
byte[] cekWrapped = Base64.decode(b64key);
byte[] iv = Base64.decode(instFile.get(Headers.CRYPTO_IV));
if (cekWrapped == null || iv == null) {
throw new CosClientException(
"Necessary encryption info not found in the instruction file " + instFile);
}
final String keyWrapAlgo = instFile.get(Headers.CRYPTO_KEYWRAP_ALGORITHM);
final boolean isKMS = isKMSKeyWrapped(keyWrapAlgo);
// Material description
String matdescStr = instFile.get(Headers.MATERIALS_DESCRIPTION);
final Map core = matdescFromJson(matdescStr);
EncryptionMaterials materials;
if (isKMS) {
materials = new KMSEncryptionMaterials(
core.get(KMSEncryptionMaterials.CUSTOMER_MASTER_KEY_ID));
materials.addDescriptions(core);
} else {
materials = kekMaterialAccessor == null ? null
: kekMaterialAccessor.getEncryptionMaterials(core);
if (materials == null) {
throw new CosClientException(
"Unable to retrieve the encryption materials that originally "
+ "encrypted object corresponding to instruction file " + instFile);
}
}
// CEK algorithm
final String cekAlgo = instFile.get(Headers.CRYPTO_CEK_ALGORITHM);
final boolean isRangeGet = range != null;
// The content crypto scheme may vary depending on whether
// it is a range get operation
ContentCryptoScheme contentCryptoScheme =
ContentCryptoScheme.fromCEKAlgo(cekAlgo, isRangeGet);
if (isRangeGet) {
// Adjust the IV as needed
iv = contentCryptoScheme.adjustIV(iv, range[0]);
} else {
// Validate the tag length supported
int tagLenExpected = contentCryptoScheme.getTagLengthInBits();
if (tagLenExpected > 0) {
String s = instFile.get(Headers.CRYPTO_TAG_LENGTH);
int tagLenActual = Integer.parseInt(s);
if (tagLenExpected != tagLenActual) {
throw new CosClientException("Unsupported tag length: " + tagLenActual
+ ", expected: " + tagLenExpected);
}
}
}
// Unwrap or decrypt the CEK
if (keyWrapExpected && keyWrapAlgo == null)
throw newKeyWrapException();
SecretKey cek =
cek(cekWrapped, keyWrapAlgo, materials, securityProvider, contentCryptoScheme, kms);
return new ContentCryptoMaterial(core, cekWrapped, keyWrapAlgo, contentCryptoScheme
.createCipherLite(cek, iv, Cipher.DECRYPT_MODE, securityProvider), null);
}
/**
* Parses instruction data retrieved from COS and returns a JSON string representing the
* instruction. Made for testing purposes.
*/
static String parseInstructionFile(COSObject instructionFile) {
try {
return convertStreamToString(instructionFile.getObjectContent());
} catch (Exception e) {
throw new CosClientException("Error parsing JSON instruction file", e);
}
}
/**
* Converts the contents of an input stream to a String
*/
private static String convertStreamToString(InputStream inputStream) throws IOException {
if (inputStream == null) {
return "";
} else {
StringBuilder stringBuilder = new StringBuilder();
String line;
try {
BufferedReader reader =
new BufferedReader(new InputStreamReader(inputStream, StringUtils.UTF8));
while ((line = reader.readLine()) != null) {
stringBuilder.append(line);
}
} finally {
inputStream.close();
}
return stringBuilder.toString();
}
}
/**
* Return the cipher lite used for content encryption/decryption purposes.
*/
CipherLite getCipherLite() {
return cipherLite;
}
/**
* Returns the description of the kek materials that were used to encrypt the cek.
*/
Map getKEKMaterialsDescription() {
return this.kekMaterialsDescription;
}
/**
* Returns an array of bytes representing the encrypted envelope symmetric key.
*
* @return an array of bytes representing the encrypted envelope symmetric key.
*/
byte[] getEncryptedCEK() {
return this.encryptedCEK.clone();
}
/**
* Recreates a new content crypto material from the current material given a new KEK
* material-descriptions. The purpose is to re-encrypt the CEK under a different KEK.
*
* Note network calls are involved if the CEK has been or is to be protected by KMS.
*
* @param newKEKMatDesc material descriptions for the new KEK; never null
* @param accessor used to retrieve the KEK given the corresponding material description
* @param targetScheme the target crypto scheme to be used for key wrapping, etc.
* @param p optional security provider; null means to use the default.
* @throws SecurityException if the old and new material description are the same; or if the old
* and new KEK are the same
*/
ContentCryptoMaterial recreate(Map newKEKMatDesc,
EncryptionMaterialsAccessor accessor, COSCryptoScheme targetScheme, Provider p,
QCLOUDKMS kms, CosServiceRequest req) {
if (!usesKMSKey() && newKEKMatDesc.equals(kekMaterialsDescription)) {
throw new SecurityException(
"Material description of the new KEK must differ from the current one");
}
final EncryptionMaterials origKEK;
if (usesKMSKey()) {
origKEK = new KMSEncryptionMaterials(
kekMaterialsDescription.get(KMSEncryptionMaterials.CUSTOMER_MASTER_KEY_ID));
} else {
origKEK = accessor.getEncryptionMaterials(kekMaterialsDescription);
if (origKEK == null) {
throw new CosClientException("Unable to retrieve the origin encryption materials");
}
}
EncryptionMaterials newKEK = accessor.getEncryptionMaterials(newKEKMatDesc);
if (newKEK == null) {
throw new CosClientException("No material available with the description "
+ newKEKMatDesc + " from the encryption material provider");
}
SecretKey cek =
cek(encryptedCEK, keyWrappingAlgorithm, origKEK, p, getContentCryptoScheme(), kms);
ContentCryptoMaterial output =
create(cek, cipherLite.getIV(), newKEK, getContentCryptoScheme(), // must use same
// content crypto
// scheme
targetScheme, p, kms, req);
if (Arrays.equals(output.encryptedCEK, encryptedCEK)) {
throw new SecurityException("The new KEK must differ from the original");
}
return output;
}
/**
* Recreates a new content crypto material from the current material given a new KEK encryption
* materials. The purpose is to re-encrypt the CEK under the new KEK.
*
* Note network calls are involved if the CEK has been or is to be protected by KMS.
*
* @param newKEK encryption materials for the new KEK; must not be null
* @param accessor used to retrieve the original KEK given the corresponding material
* description
* @param targetScheme the target crypto scheme to use for recreating the content crypto
* material
* @param p optional security provider; null means to use the default.
* @throws SecurityException if the old and new material description are the same; or if the old
* and new KEK are the same
*/
ContentCryptoMaterial recreate(EncryptionMaterials newKEK, EncryptionMaterialsAccessor accessor,
COSCryptoScheme targetScheme, Provider p, QCLOUDKMS kms, CosServiceRequest req) {
if (!usesKMSKey() && newKEK.getMaterialsDescription().equals(kekMaterialsDescription)) {
throw new SecurityException(
"Material description of the new KEK must differ from the current one");
}
final EncryptionMaterials origKEK;
if (usesKMSKey()) {
origKEK = new KMSEncryptionMaterials(
kekMaterialsDescription.get(KMSEncryptionMaterials.CUSTOMER_MASTER_KEY_ID));
} else {
origKEK = accessor.getEncryptionMaterials(kekMaterialsDescription);
if (origKEK == null) {
throw new CosClientException("Unable to retrieve the origin encryption materials");
}
}
SecretKey cek =
cek(encryptedCEK, keyWrappingAlgorithm, origKEK, p, getContentCryptoScheme(), kms);
ContentCryptoMaterial output =
create(cek, cipherLite.getIV(), newKEK, getContentCryptoScheme(), // must use same
// content crypto
// scheme
targetScheme, // target scheme used to recreate the content crypto material
p, kms, req);
if (Arrays.equals(output.encryptedCEK, encryptedCEK)) {
throw new SecurityException("The new KEK must differ from the original");
}
return output;
}
/**
* Returns a new instance of ContentCryptoMaterial for the input parameters using
* the specified content crypto scheme, and the key wrapping and secure randomness specified of
* the specified cos crypto scheme.
*
* Note network calls are involved if the CEK is to be protected by KMS.
*
* @param cek content encrypting key; must not be null.
* @param iv initialization vector; must not be null.
* @param contentCryptoScheme content crypto scheme to be used
* @param targetScheme the target cos crypto scheme to be used for recreating the content crypto
* material by providing the key wrapping scheme and mechanism for secure randomness
* @param provider optional security provider
*/
static ContentCryptoMaterial create(SecretKey cek, byte[] iv, EncryptionMaterials kekMaterials,
ContentCryptoScheme contentCryptoScheme, COSCryptoScheme targetScheme,
Provider provider, QCLOUDKMS kms, CosServiceRequest req) {
return doCreate(cek, iv, kekMaterials, contentCryptoScheme, targetScheme, provider, kms,
req);
}
/**
* Returns a new instance of ContentCryptoMaterial for the input parameters using
* the specified cos crypto scheme. Note network calls are involved if the CEK is to be
* protected by KMS.
*
* @param cek content encrypting key
* @param iv initialization vector
* @param kekMaterials kek encryption material used to secure the CEK; can be KMS enabled.
* @param scheme cos crypto scheme to be used for the content crypto material by providing the
* content crypto scheme, key wrapping scheme and mechanism for secure randomness
* @param provider optional security provider
* @param kms reference to the KMS client
* @param req originating service request
*/
static ContentCryptoMaterial create(SecretKey cek, byte[] iv, EncryptionMaterials kekMaterials,
COSCryptoScheme scheme, Provider provider, QCLOUDKMS kms, CosServiceRequest req) {
return doCreate(cek, iv, kekMaterials, scheme.getContentCryptoScheme(), scheme, provider,
kms, req);
}
/**
* Returns a new instance of ContentCryptoMaterial for the given input parameters
* by using the specified content crypto scheme, and COS crypto scheme.
*
* Note network calls are involved if the CEK is to be protected by KMS.
*
* @param cek content encrypting key
* @param iv initialization vector
* @param kekMaterials kek encryption material used to secure the CEK; can be KMS enabled.
* @param contentCryptoScheme content crypto scheme to be used, which can differ from the one of
* targetCOSCryptoScheme
* @param targetCOSCryptoScheme the target cos crypto scheme to be used for providing the key
* wrapping scheme and mechanism for secure randomness
* @param provider security provider
* @param kms reference to the KMS client
* @param req the originating COS service request
*/
private static ContentCryptoMaterial doCreate(SecretKey cek, byte[] iv,
EncryptionMaterials kekMaterials, ContentCryptoScheme contentCryptoScheme,
COSCryptoScheme targetCOSCryptoScheme, Provider provider, QCLOUDKMS kms,
CosServiceRequest req) {
// Secure the envelope symmetric key either by encryption, key wrapping
// or KMS.
SecuredCEK cekSecured =
secureCEK(cek, kekMaterials, targetCOSCryptoScheme.getKeyWrapScheme(),
targetCOSCryptoScheme.getSecureRandom(), provider, kms, req);
byte[] securedIV =
encryptIV(iv, kekMaterials, targetCOSCryptoScheme.getKeyWrapScheme(),
targetCOSCryptoScheme.getSecureRandom(), provider, kms, req);
return wrap(cek, iv, contentCryptoScheme, provider, cekSecured, securedIV);
}
/**
* Returns a new instance of ContentCryptoMaterial by wrapping the input
* parameters, including the already secured CEK. No network calls are involved.
*/
public static ContentCryptoMaterial wrap(SecretKey cek, byte[] iv,
ContentCryptoScheme contentCryptoScheme, Provider provider, SecuredCEK cekSecured, byte[] securedIV) {
return new ContentCryptoMaterial(cekSecured.getMaterialDescription(),
cekSecured.getEncrypted(), cekSecured.getKeyWrapAlgorithm(),
contentCryptoScheme.createCipherLite(cek, iv, Cipher.ENCRYPT_MODE, provider), securedIV);
}
/**
* Secure the given CEK. Note network calls are involved if the CEK is to be protected by KMS.
*
* @param cek content encrypting key to be secured
* @param materials used to provide the key-encryption-key (KEK); or if it is KMS-enabled, the
* customer master key id and material description.
* @param contentCryptoScheme the content crypto scheme
* @param p optional security provider; can be null if the default is used.
* @return a secured CEK in the form of ciphertext or ciphertext blob.
*/
private static SecuredCEK secureCEK(SecretKey cek, EncryptionMaterials materials,
COSKeyWrapScheme kwScheme, SecureRandom srand, Provider p, QCLOUDKMS kms,
CosServiceRequest req) {
final Map matdesc;
if (materials.isKMSEnabled()) {
matdesc = mergeMaterialDescriptions(materials, req);
EncryptRequest encryptRequest = new EncryptRequest();
try {
ObjectMapper mapper = new ObjectMapper();
encryptRequest.setEncryptionContext(mapper.writeValueAsString(matdesc));
} catch (JsonProcessingException e) {
throw new CosClientException("encrypt request set encryption context got json processing exception", e);
}
encryptRequest.setKeyId(materials.getCustomerMasterKeyId());
encryptRequest.setPlaintext(cek.getEncoded().toString());
EncryptResponse encryptResponse = kms.encrypt(encryptRequest);
byte[] keyBlob = encryptResponse.getCiphertextBlob().getBytes();
return new KMSSecuredCEK(keyBlob, matdesc);
} else {
matdesc = materials.getMaterialsDescription();
}
Key kek;
if (materials.getKeyPair() != null) {
// Do envelope encryption with public key from key pair
kek = materials.getKeyPair().getPublic();
} else {
// Do envelope encryption with symmetric key
kek = materials.getSymmetricKey();
}
String keyWrapAlgo = kwScheme.getKeyWrapAlgorithm(kek);
try {
Cipher cipher = p == null ? Cipher.getInstance(keyWrapAlgo)
: Cipher.getInstance(keyWrapAlgo, p);
cipher.init(Cipher.WRAP_MODE, kek, srand);
return new SecuredCEK(cipher.wrap(cek), keyWrapAlgo, matdesc);
} catch (Exception e) {
throw new CosClientException("Unable to encrypt symmetric key", e);
}
}
public static byte[] encryptIV(byte[] iv, EncryptionMaterials materials,
COSKeyWrapScheme kwScheme, SecureRandom srand, Provider p, QCLOUDKMS kms,
CosServiceRequest req) {
if (materials.isKMSEnabled()) {
Map matdesc = mergeMaterialDescriptions(materials, req);
EncryptRequest encryptRequest = new EncryptRequest();
try {
ObjectMapper mapper = new ObjectMapper();
encryptRequest.setEncryptionContext(mapper.writeValueAsString(matdesc));
} catch (JsonProcessingException e) {
throw new CosClientException("encrypt request set encryption context got json processing exception", e);
}
encryptRequest.setKeyId(materials.getCustomerMasterKeyId());
encryptRequest.setPlaintext(Base64.encodeAsString(iv));
EncryptResponse encryptResponse = kms.encrypt(encryptRequest);
String cipherIV = encryptResponse.getCiphertextBlob();
return cipherIV.getBytes(Charset.forName("UTF-8"));
}
Key kek;
if (materials.getKeyPair() != null) {
// Do envelope encryption with public key from key pair
kek = materials.getKeyPair().getPublic();
} else {
// Do envelope encryption with symmetric key
kek = materials.getSymmetricKey();
}
String keyWrapAlgo = kwScheme.getKeyWrapAlgorithm(kek);
try {
Cipher cipher = p == null ? Cipher.getInstance(keyWrapAlgo)
: Cipher.getInstance(keyWrapAlgo, p);
cipher.init(Cipher.ENCRYPT_MODE, kek, srand);
return cipher.doFinal(iv);
} catch (Exception e) {
throw new CosClientException("Unable to encrypt IV", e);
}
}
public static byte[] decryptIV(byte[] iv, String keyWrapAlgo,
EncryptionMaterials materials, Provider securityProvider,
ContentCryptoScheme contentCryptoScheme, QCLOUDKMS kms) {
if (materials.isKMSEnabled()) {
DecryptRequest decryptReq = new DecryptRequest();
Map materialDesc = materials.getMaterialsDescription();
try {
ObjectMapper mapper = new ObjectMapper();
decryptReq.setEncryptionContext(mapper.writeValueAsString(materialDesc));
} catch (JsonProcessingException e) {
throw new CosClientException("decrypt request set encryption context got json processing exception", e);
}
decryptReq.setCiphertextBlob(new String(iv, Charset.forName("UTF-8")));
DecryptResponse decryptRes = kms.decrypt(decryptReq);
return Base64.decode(decryptRes.getPlaintext());
}
Key kek;
if (materials.getKeyPair() != null) {
// Do envelope decryption with private key from key pair
kek = materials.getKeyPair().getPrivate();
if (kek == null) {
throw new CosClientException("Key encrypting key not available");
}
} else {
// Do envelope decryption with symmetric key
kek = materials.getSymmetricKey();
if (kek == null) {
throw new CosClientException("Key encrypting key not available");
}
}
try {
if (keyWrapAlgo != null) {
// Key wrapping specified
Cipher cipher = securityProvider == null ? Cipher.getInstance(keyWrapAlgo)
: Cipher.getInstance(keyWrapAlgo, securityProvider);
cipher.init(Cipher.DECRYPT_MODE, kek);
return cipher.doFinal(iv);
}
// fall back to the Encryption Only (EO) key decrypting method
Cipher cipher;
if (securityProvider != null) {
cipher = Cipher.getInstance(kek.getAlgorithm(), securityProvider);
} else {
cipher = Cipher.getInstance(kek.getAlgorithm());
}
cipher.init(Cipher.DECRYPT_MODE, kek);
return cipher.doFinal(iv);
} catch (Exception e) {
throw new CosClientException("Unable to decrypt symmetric key from object metadata", e);
}
}
static Map mergeMaterialDescriptions(EncryptionMaterials materials,
CosServiceRequest req) {
Map matdesc = materials.getMaterialsDescription();
if (req instanceof MaterialsDescriptionProvider) {
MaterialsDescriptionProvider mdp = (MaterialsDescriptionProvider) req;
Map matdesc_req = mdp.getMaterialsDescription();
if (matdesc_req != null) {
matdesc = new TreeMap(matdesc);
matdesc.putAll(matdesc_req); // request takes precedence
}
}
return matdesc;
}
}