ganfra
11 months ago
4 changed files with 96 additions and 72 deletions
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/* |
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* Copyright (c) 2023 New Vector Ltd |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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package io.element.android.libraries.cryptography.api |
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import javax.crypto.Cipher |
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/** |
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* Factory to create [Cipher] instances for encryption and decryption. |
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* The implementation should use a secure way to store the keys. |
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*/ |
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interface CipherFactory { |
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/** |
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* Create a [Cipher] instance for encryption. |
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* @param alias the alias of the key used for encryption. |
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* @return the [Cipher] instance. |
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*/ |
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fun createEncryptionCipher(alias: String): Cipher |
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/** |
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* Create a [Cipher] instance for decryption. |
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* @param alias the alias of the key used for encryption. |
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* @param initializationVector the initialization vector used for encryption. |
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* @return the [Cipher] instance. |
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*/ |
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fun createDecryptionCipher(alias: String, initializationVector: ByteArray): Cipher |
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} |
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/* |
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* Copyright (c) 2023 New Vector Ltd |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0 |
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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package io.element.android.libraries.cryptography.api |
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import android.util.Base64 |
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import java.nio.ByteBuffer |
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/** |
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* Holds the result of an encryption operation. |
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*/ |
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class EncryptionResult( |
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val encryptedByteArray: ByteArray, |
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val initializationVector: ByteArray |
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) { |
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fun toBase64(): String { |
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val initializationVectorSize = ByteBuffer.allocate(Int.SIZE_BYTES).putInt(initializationVector.size).array() |
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val cipherTextWithIv: ByteArray = |
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ByteBuffer.allocate(Int.SIZE_BYTES + initializationVector.size + encryptedByteArray.size) |
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.put(initializationVectorSize) |
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.put(initializationVector) |
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.put(encryptedByteArray) |
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.array() |
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return Base64.encodeToString(cipherTextWithIv, Base64.NO_WRAP) |
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} |
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companion object { |
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/** |
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* @param base64 the base64 representation of the encrypted data. |
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* @return the [EncryptionResult] from the base64 representation. |
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*/ |
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fun fromBase64(base64: String): EncryptionResult { |
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val cipherTextWithIv = Base64.decode(base64, Base64.NO_WRAP) |
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val buffer = ByteBuffer.wrap(cipherTextWithIv) |
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val initializationVectorSize = buffer.int |
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val initializationVector = ByteArray(initializationVectorSize) |
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buffer.get(initializationVector) |
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val encryptedByteArray = ByteArray(buffer.remaining()) |
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buffer.get(encryptedByteArray) |
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return EncryptionResult(encryptedByteArray, initializationVector) |
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} |
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} |
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} |
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