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Export backupV2 using actual desired file format.

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This commit is contained in:
Greyson Parrelli
2023-11-21 11:22:15 -05:00
committed by Cody Henthorne
parent fb69fc5af2
commit befa396e82
42 changed files with 1565 additions and 424 deletions
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17
libsignal-service/src/main/java/org/whispersystems/signalservice/api/backup/BackupId.kt Normal file
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@@ -0,0 +1,17 @@
/*
* Copyright 2023 Signal Messenger, LLC
* SPDX-License-Identifier: AGPL-3.0-only
*/
package org.whispersystems.signalservice.api.backup
/**
* Safe typing around a backupId, which is a 16-byte array.
*/
@JvmInline
value class BackupId(val value: ByteArray) {
init {
require(value.size == 16) { "BackupId must be 16 bytes!" }
}
}

40
libsignal-service/src/main/java/org/whispersystems/signalservice/api/backup/BackupKey.kt Normal file
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@@ -0,0 +1,40 @@
/*
* Copyright 2023 Signal Messenger, LLC
* SPDX-License-Identifier: AGPL-3.0-only
*/
package org.whispersystems.signalservice.api.backup
import org.signal.libsignal.protocol.kdf.HKDF
import org.whispersystems.signalservice.api.push.ServiceId.ACI
/**
* Safe typing around a backup key, which is a 32-byte array.
*/
class BackupKey(val value: ByteArray) {
init {
require(value.size == 32) { "Backup key must be 32 bytes!" }
}
fun deriveSecrets(aci: ACI): KeyMaterial {
val backupId = BackupId(
HKDF.deriveSecrets(this.value, aci.toByteArray(), "20231003_Signal_Backups_GenerateBackupId".toByteArray(), 16)
)
val extendedKey = HKDF.deriveSecrets(this.value, backupId.value, "20231003_Signal_Backups_EncryptMessageBackup".toByteArray(), 80)
return KeyMaterial(
backupId = backupId,
macKey = extendedKey.copyOfRange(0, 32),
cipherKey = extendedKey.copyOfRange(32, 64),
iv = extendedKey.copyOfRange(64, 80)
)
}
class KeyMaterial(
val backupId: BackupId,
val macKey: ByteArray,
val cipherKey: ByteArray,
val iv: ByteArray
)
}

6
libsignal-service/src/main/java/org/whispersystems/signalservice/api/kbs/MasterKey.java
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@@ -1,5 +1,7 @@
package org.whispersystems.signalservice.api.kbs;
import org.signal.libsignal.protocol.kdf.HKDF;
import org.whispersystems.signalservice.api.backup.BackupKey;
import org.whispersystems.signalservice.api.storage.StorageKey;
import org.whispersystems.signalservice.internal.util.Hex;
import org.signal.core.util.Base64;
@@ -44,6 +46,10 @@ public final class MasterKey {
return derive("Logging Key");
}
public BackupKey deriveBackupKey() {
return new BackupKey(HKDF.deriveSecrets(masterKey, "20231003_Signal_Backups_GenerateBackupKey".getBytes(), 32));
}
private byte[] derive(String keyName) {
return hmacSha256(masterKey, StringUtil.utf8(keyName));
}