Module org.cryptomator.cryptolib

Package org.cryptomator.cryptolib.api

Interface FileNameCryptor

public interface FileNameCryptor

Provides deterministic encryption capabilities as filenames must not change on subsequent encryption attempts, otherwise each change results in major directory structure changes which would be a terrible idea for cloud storage encryption.

See Also:

• Wikipedia on deterministic encryption

Method Summary

Modifier and Type	Method	Description
String	decryptFilename(com.google.common.io.BaseEncoding encoding, String ciphertextName, byte[]... associatedData)
String	encryptFilename(com.google.common.io.BaseEncoding encoding, String cleartextName, byte[]... associatedData)
String	hashDirectoryId(String cleartextDirectoryId)

Method Details

hashDirectoryId

String hashDirectoryId(String cleartextDirectoryId)

Parameters:

cleartextDirectoryId - an arbitrary directory id to be passed to one-way hash function

Returns:

constant length string, that is unlikely to collide with any other name.

encryptFilename

String encryptFilename(com.google.common.io.BaseEncoding encoding,
 String cleartextName,
 byte[]... associatedData)

Parameters:

encoding - Encoding to use to encode the returned ciphertext

cleartextName - original filename including cleartext file extension

associatedData - optional associated data, that will not get encrypted but needs to be provided during decryption

Returns:

encrypted filename without any file extension

decryptFilename

String decryptFilename(com.google.common.io.BaseEncoding encoding,
 String ciphertextName,
 byte[]... associatedData)
                throws AuthenticationFailedException

Parameters:

encoding - Encoding to use to decode ciphertextName

ciphertextName - Ciphertext only, with any additional strings like file extensions stripped first.

associatedData - the same associated data used during encryption, otherwise and AuthenticationFailedException will be thrown

Returns:

cleartext filename, probably including its cleartext file extension.

Throws:

AuthenticationFailedException - if the ciphertext is malformed