| 1 |
efrain |
1 |
<?php
|
|
|
2 |
namespace Aws\Crypto;
|
|
|
3 |
|
|
|
4 |
abstract class MaterialsProvider implements MaterialsProviderInterface
|
|
|
5 |
{
|
|
|
6 |
private static $supportedKeySizes = [
|
|
|
7 |
128 => true,
|
|
|
8 |
192 => true,
|
|
|
9 |
256 => true,
|
|
|
10 |
];
|
|
|
11 |
|
|
|
12 |
/**
|
|
|
13 |
* Returns if the requested size is supported by AES.
|
|
|
14 |
*
|
|
|
15 |
* @param int $keySize Size of the requested key in bits.
|
|
|
16 |
*
|
|
|
17 |
* @return bool
|
|
|
18 |
*/
|
|
|
19 |
public static function isSupportedKeySize($keySize)
|
|
|
20 |
{
|
|
|
21 |
return isset(self::$supportedKeySizes[$keySize]);
|
|
|
22 |
}
|
|
|
23 |
|
|
|
24 |
/**
|
|
|
25 |
* Performs further initialization of the MaterialsProvider based on the
|
|
|
26 |
* data inside the MetadataEnvelope.
|
|
|
27 |
*
|
|
|
28 |
* @param MetadataEnvelope $envelope A storage envelope for encryption
|
|
|
29 |
* metadata to be read from.
|
|
|
30 |
*
|
|
|
31 |
* @return MaterialsProvider
|
|
|
32 |
*
|
|
|
33 |
* @throws \RuntimeException Thrown when there is an empty or improperly
|
|
|
34 |
* formed materials description in the envelope.
|
|
|
35 |
*
|
|
|
36 |
* @internal
|
|
|
37 |
*/
|
|
|
38 |
abstract public function fromDecryptionEnvelope(MetadataEnvelope $envelope);
|
|
|
39 |
|
|
|
40 |
/**
|
|
|
41 |
* Returns the material description for this Provider so it can be verified
|
|
|
42 |
* by encryption mechanisms.
|
|
|
43 |
*
|
|
|
44 |
* @return string
|
|
|
45 |
*/
|
|
|
46 |
abstract public function getMaterialsDescription();
|
|
|
47 |
|
|
|
48 |
/**
|
|
|
49 |
* Returns the wrap algorithm name for this Provider.
|
|
|
50 |
*
|
|
|
51 |
* @return string
|
|
|
52 |
*/
|
|
|
53 |
abstract public function getWrapAlgorithmName();
|
|
|
54 |
|
|
|
55 |
/**
|
|
|
56 |
* Takes a content encryption key (CEK) and description to return an
|
|
|
57 |
* encrypted key according to the Provider's specifications.
|
|
|
58 |
*
|
|
|
59 |
* @param string $unencryptedCek Key for use in encrypting other data
|
|
|
60 |
* that itself needs to be encrypted by the
|
|
|
61 |
* Provider.
|
|
|
62 |
* @param string $materialDescription Material Description for use in
|
|
|
63 |
* encrypting the $cek.
|
|
|
64 |
*
|
|
|
65 |
* @return string
|
|
|
66 |
*/
|
|
|
67 |
abstract public function encryptCek($unencryptedCek, $materialDescription);
|
|
|
68 |
|
|
|
69 |
/**
|
|
|
70 |
* Takes an encrypted content encryption key (CEK) and material description
|
|
|
71 |
* for use decrypting the key according to the Provider's specifications.
|
|
|
72 |
*
|
|
|
73 |
* @param string $encryptedCek Encrypted key to be decrypted by the Provider
|
|
|
74 |
* for use decrypting other data.
|
|
|
75 |
* @param string $materialDescription Material Description for use in
|
|
|
76 |
* encrypting the $cek.
|
|
|
77 |
*
|
|
|
78 |
* @return string
|
|
|
79 |
*/
|
|
|
80 |
abstract public function decryptCek($encryptedCek, $materialDescription);
|
|
|
81 |
|
|
|
82 |
/**
|
|
|
83 |
* @param string $keySize Length of a cipher key in bits for generating a
|
|
|
84 |
* random content encryption key (CEK).
|
|
|
85 |
*
|
|
|
86 |
* @return string
|
|
|
87 |
*/
|
|
|
88 |
public function generateCek($keySize)
|
|
|
89 |
{
|
|
|
90 |
return openssl_random_pseudo_bytes($keySize / 8);
|
|
|
91 |
}
|
|
|
92 |
|
|
|
93 |
/**
|
|
|
94 |
* @param string $openSslName Cipher OpenSSL name to use for generating
|
|
|
95 |
* an initialization vector.
|
|
|
96 |
*
|
|
|
97 |
* @return string
|
|
|
98 |
*/
|
|
|
99 |
public function generateIv($openSslName)
|
|
|
100 |
{
|
|
|
101 |
return openssl_random_pseudo_bytes(
|
|
|
102 |
openssl_cipher_iv_length($openSslName)
|
|
|
103 |
);
|
|
|
104 |
}
|
|
|
105 |
}
|