AESFile Class

Properties   Methods   Events   Config Settings   Errors  

The AESFile class implements the AESF file format and uses the XTS-AES standard with 256-bit encryption.

Syntax

ipworksencrypt.AESFile

Remarks

The AESFile component provides robust encryption capabilities to securely store and retrieve data using XTS-AES 256-bit encryption. This component implements the AESF file format, enabling developers to encrypt arbitrary data and serialize it in a standardized manner.

The first step in using the component is to set Password property. Specify the input data using InputFile or InputMessage. Next, call Encrypt and the component will encrypt the input data and populate OutputMessage, or write to the file specified by OutputFile with the result.

To change the password of existing file encrypted in AESF format, or to encrypt a file under a different password call ChangePassword. To decrypt data, first set Password property. Specify the input data using InputFile or InputMessage. Next, call Decrypt and the component will compute the plaintext and populate OutputMessage or write to OutputFile with the result.

AES File Format

The AES file format used by AES Drive is documented below in detail. All algorithms used by AES Drive are standards and publicly documented.

Each encrypted file consists of a header and the encrypted contents. The header is 144 bytes in length and contains the AES file format version, a checksum of the header bytes, and the encrypted file-specific key and padding length. The original file data is encrypted using XTS-AES with file-specific keys that are derived from a master key for the drive.

4 bytes [0-3] AESF. This is a file signature value which indicates the file is formatted according to this specification.
1 byte [4] 0x01. This is the file format version. This documentation defines the format for version 1.
2 bytes [5-6] Build number of the application used to create the file. These two bytes represent a 16-bit integer holding the build number of AES Drive that created the file. This field is informational only. Byte 5 holds the high-order bits and byte 6 holds the low-order bits. To decode these bytes into the build number the following code may be used: int buildNumber = headerBytes[5] << 8 | headerBytes[6];
5 bytes [7-11] 0x00. Reserved for future use.
4 bytes [12-15] CRC32 checksum. The CRC32 checksum is calculated by first replacing these 4 bytes with 0x00 then computing the checksum over the 144 byte header. The resulting numeric value is converted into 4 bytes using the operation:

byte[] CRC32Bytes = new byte[4]; for (int i = 0; i < 4; i++) CRC32Bytes[i] = (byte)((CRC32Bytes >> (24 - 8 * i)) & 0xff);

16 bytes [16-31] Global salt value. The global salt value is a random value created when the drive is created and used when encrypting newly created files within the drive. It is used when deriving the key to decrypt the encrypted header portion. See the section below for details about the encrypted header portion.
16 bytes [32-47] File-specific salt value. The file-specific salt value is a random value created when the file is created. It is used when deriving the key to decrypt the encrypted header portion. See the section below for details about the encrypted header portion.
80 bytes [48-127] AES-GCM encrypted header portion. The steps to derive the key to decrypt the encrypted header portion are as follows:
  • First use PBKDF2 with the following settings:
    • HMACSHA512 algorithm
    • 50,000 iterations
    • Salt is the 16 byte global salt value read from the header
    • Password is the original encryption password
    • Derived key length of 32 bytes
  • Combine the 16 byte file-specific salt with the 32 byte derived key to obtain a byte array of length 48. The first 16 bytes are the file-specific salt read from the file header. The last 32 bytes are the value derived from the PBKDF process above.
  • Compute the SHA512 hash over the 48 byte value from the above step.
  • The first 32 bytes of the hashed bytes are the AES-GCM key. The next 12 bytes are the AES-GCM IV. The remaining 20 bytes are unused.

The derived Key and IV are used together with the AES-GCM Auth Tag which are the last 16 bytes of the 144 byte header to AES-GCM decrypt the 80 byte encrypted header portion. The decrypted header portion contains:

2 bytes Padding length. The padding length is represented in Big Endian and may be converted from bytes to an integer using the following operation: PaddingLen = (decryptedHeaderBytes[0] << 8) + decryptedHeaderBytes[1];
14 bytes 0x00. Reserved. These bytes are all defined as 0x00.
64 bytes File-specific XTS-AES 256 encryption keys.

16 bytes [128-143] AES-GCM auth tag. This auth tag is used when decrypting the previous 80 byte encrypted header portion.
nn bytes The XTS-AES 256 encrypted file content. The data unit size is 512 bytes. The first 32 bytes of the file-specific encryption key from the decrypted header is the first key. The last 32 bytes of the file-specific encryption key from the decrypted header is the second key.
512 bytes

The last 512 bytes of the encrypted file contain encrypted padding bytes and additional unencrypted random bytes.

When encrypting, the last plaintext block of data may be padded with random bytes as needed to reach 512 bytes in length (the data unit size). The padding length is encrypted and stored in the encrypted header portion. Once the data is encrypted additional random bytes are appended to the end of the encrypted file so that the padding bytes plus additional random bytes together are 512 bytes in length.

For instance if the padding is 100 bytes in length, then 412 additional bytes will be appended to the encrypted data to reach a total of 512 bytes. This scheme allows applications to easily determine the length of the decrypted file without having to first decrypt the encrypted header portion to obtain the padding length. The decrypted file length can be computed like so: long decryptedFileLength = encryptedFileLength - 144 - 512. //Subtract 144 for the header length //Subtract 512 for the combination of padding bytes and additional random bytes

When decrypting, the padding length is determined from the encrypted header. The number of additional random bytes is 512 minus the padding length. The additional random bytes are discarded before using XTS-AES to decrypt the file content. After decrypting the file content, the padding bytes in the decrypted content are discarded.

// structure of the end of the encrypted file [512 bytes] | -------------------------------------------------- | | encrypted_content | encrypted_padding_bytes | additional_random_bytes

Property List

The following is the full list of the properties of the class with short descriptions. Click on the links for further details.

GlobalSaltThe additional random data to compute encryption keys.
InputFileThe file to process.
InputMessageThe message to process.
OutputFileThe output file when encrypting or decrypting.
OutputMessageThe output message after processing.
OverwriteIndicates whether or not the class should overwrite files.
PasswordThe password to be used to calculate encryption and decryption keys.
SaltThe additional random data included in the file header.
VersionThe AESF file format version number.

Method List

The following is the full list of the methods of the class with short descriptions. Click on the links for further details.

ChangePasswordChanges the password for the specified file.
ConfigSets or retrieves a configuration setting.
DecryptDecrypts the data.
EncryptEncrypts the data.
ResetResets the class.
SetInputStreamSets the stream from which the class will read data to encrypt or decrypt.
SetOutputStreamSets the stream to which the class will write encrypted or decrypted data.

Event List

The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.

ErrorFired when information is available about errors during data delivery.
LogFires with log information during processing.
ProgressFired as progress is made.

Config Settings

The following is a list of config settings for the class with short descriptions. Click on the links for further details.

BuildNumberThe build number of the encrypted data.
CloseInputStreamAfterProcessingDetermines whether or not the input stream is closed after processing.
CloseOutputStreamAfterProcessingDetermines whether or not the output stream is closed after processing.
LogLevelSpecifies the level of detail that is logged.
WriteToProgressEventWhether to write output data so it is accessible from inside the progress event.
BuildInfoInformation about the product's build.
GUIAvailableWhether or not a message loop is available for processing events.
LicenseInfoInformation about the current license.
MaskSensitiveDataWhether sensitive data is masked in log messages.
UseDaemonThreadsWhether threads created by the class are daemon threads.
UseFIPSCompliantAPITells the class whether or not to use FIPS certified APIs.
UseInternalSecurityAPIWhether or not to use the system security libraries or an internal implementation.

GlobalSalt Property (AESFile Class)

The additional random data to compute encryption keys.

Syntax

public byte[] getGlobalSalt();
public void setGlobalSalt(byte[] globalSalt);

Default Value

""

Remarks

This is an optional property and will be populated when Decrypt is called. When this property is set, it will provide additional randomness to encryption. The length of the salt must be 16 bytes.

The global salt will be used during generation of a key and IV. It can optionally be set before calling the Encrypt method. It is recommended to use a unique and randomly generated value. If it is not set, then the class will generate a value automatically.

InputFile Property (AESFile Class)

The file to process.

Syntax

public String getInputFile();
public void setInputFile(String inputFile);

Default Value

""

Remarks

This property specifies the file to be processed. Set this property to the full or relative path to the file which will be processed.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

InputMessage Property (AESFile Class)

The message to process.

Syntax

public byte[] getInputMessage();
public void setInputMessage(byte[] inputMessage);

Default Value

""

Remarks

This property specifies the message to be processed.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

OutputFile Property (AESFile Class)

The output file when encrypting or decrypting.

Syntax

public String getOutputFile();
public void setOutputFile(String outputFile);

Default Value

""

Remarks

This property specifies the file to which the output will be written when Encrypt or Decrypt is called. This may be set to an absolute or relative path.

This property is only applicable to Encrypt and Decrypt.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

OutputMessage Property (AESFile Class)

The output message after processing.

Syntax

public byte[] getOutputMessage();

Default Value

""

Remarks

This property will be populated with the output from the operation if OutputFile and SetOutputStream are not set.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

This property is read-only and not available at design time.

Overwrite Property (AESFile Class)

Indicates whether or not the class should overwrite files.

Syntax

public boolean isOverwrite();
public void setOverwrite(boolean overwrite);

Default Value

False

Remarks

This property indicates whether or not the class will overwrite OutputFile. If Overwrite is False, an error will be thrown whenever OutputFile exists before an operation. The default value is False.

Password Property (AESFile Class)

The password to be used to calculate encryption and decryption keys.

Syntax

public String getPassword();
public void setPassword(String password);

Default Value

""

Remarks

When this property is set the class will use PBKDF2 to derive an XTS master key. This must be set before calling Encrypt or Decrypt.

While there are no strict format or length requirements, it is recommended to use complex passwords. Once set, the password is transformed and never held in plaintext in memory.

Salt Property (AESFile Class)

The additional random data included in the file header.

Syntax

public byte[] getSalt();
public void setSalt(byte[] salt);

Default Value

""

Remarks

This property is optional and will be populated when Decrypt is called. When this property is set it will provide additional randomness to encryption at the file level. The length of the salt must be 16 bytes.

The salt will be used within each file as input to encryption. It can optionally be set before calling the Encrypt method. It is recommended to use a unique and randomly generated value. If it is not set, then the class will generate a value automatically.

Version Property (AESFile Class)

The AESF file format version number.

Syntax

public int getVersion();
public void setVersion(int version);

Default Value

1

Remarks

This property will be populated when Decrypt is called. Possible values are:

1 (v1 - Default)

ChangePassword Method (AESFile Class)

Changes the password for the specified file.

Syntax

public void changePassword(String path, String oldPassword, String newPassword);

Remarks

ChangePassword is optional and allows you to update the password used to encrypt an AESF file. This securely changes the password, ensuring that the file remains protected with the new password.

Config Method (AESFile Class)

Sets or retrieves a configuration setting.

Syntax

public String config(String configurationString);

Remarks

Config is a generic method available in every class. It is used to set and retrieve configuration settings for the class.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

Decrypt Method (AESFile Class)

Decrypts the data.

Syntax

public void decrypt();

Remarks

This method will decrypt the specified data. The Password property is required.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

Encrypt Method (AESFile Class)

Encrypts the data.

Syntax

public void encrypt();

Remarks

This method will encrypt the specified data. The following properties are applicable:

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

Reset Method (AESFile Class)

Resets the class.

Syntax

public void reset();

Remarks

When called, the class will reset all of its properties to their default values.

SetInputStream Method (AESFile Class)

Sets the stream from which the class will read data to encrypt or decrypt.

Syntax

public void setInputStream(java.io.InputStream inputStream);

Remarks

This method sets the stream from which the class will read data to encrypt or decrypt.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

SetOutputStream Method (AESFile Class)

Sets the stream to which the class will write encrypted or decrypted data.

Syntax

public void setOutputStream(java.io.OutputStream outputStream);

Remarks

This method sets the stream to which the class will write encrypted or decrypted data.

Input and Output Properties

The class will determine the source and destination of the input and output based on which properties are set.

The order in which the input properties are checked is as follows:

When a valid source is found, the search stops. The order in which the output properties are checked is as follows:

  • SetOutputStream
  • OutputFile
  • OutputMessage: The output data is written to this property if no other destination is specified.

When using streams, you may need to additionally set CloseInputStreamAfterProcessing or CloseOutputStreamAfterProcessing.

Error Event (AESFile Class)

Fired when information is available about errors during data delivery.

Syntax

public class DefaultAESFileEventListener implements AESFileEventListener {
  ...
  public void error(AESFileErrorEvent e) {}
  ...
}

public class AESFileErrorEvent {
  public int errorCode;
  public String description;
}

Remarks

The Error event is fired in case of exceptional conditions during message processing. Normally the class throws an exception.

The ErrorCode parameter contains an error code, and the Description parameter contains a textual description of the error. For a list of valid error codes and their descriptions, please refer to the Error Codes section.

Log Event (AESFile Class)

Fires with log information during processing.

Syntax

public class DefaultAESFileEventListener implements AESFileEventListener {
  ...
  public void log(AESFileLogEvent e) {}
  ...
}

public class AESFileLogEvent {
  public int logLevel;
  public String message;
  public String logType;
}

Remarks

This event fires during processing with log information. The level of detail that is logged is controlled via the LogLevel.

LogLevel indicates the level of message. Possible values are:

0 (None) No events are logged.
1 (Info - default) Informational events are logged.
2 (Verbose) Detailed data is logged.
3 (Debug) Debug data is logged.

LogMessage is the log entry.

LogType indicates the type of log. Possible values are:

  • "INFO"
  • "ENCRYPT"
  • "COMPRESS"
  • "SIGN"
  • "DECRYPT"
  • "DECOMPRESS"
  • "VERIFY"
  • "DEBUG"

Progress Event (AESFile Class)

Fired as progress is made.

Syntax

public class DefaultAESFileEventListener implements AESFileEventListener {
  ...
  public void progress(AESFileProgressEvent e) {}
  ...
}

public class AESFileProgressEvent {
  public byte[] data;
  public String filename;
  public long bytesProcessed;
  public int percentProcessed;
}

Remarks

This event is fired automatically as data is encrypted or decrypted by the class. When WriteToProgressEvent is true, the output data is provided through the Data parameter, allowing for it to be streamed out.

Filename contains the name of the file being written. If no file is being written, Filename will contain an empty string, and the output data will be provided exclusively through this event.

The PercentProcessed parameter indicates the current status of the operation.

The BytesProcessed parameter holds the total number of bytes processed so far.

Config Settings (AESFile Class)

The class accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the class, access to these internal properties is provided through the Config method.

AESFile Config Settings

BuildNumber:   The build number of the encrypted data.

This property will be populated when Decrypt is called, and will be set to the current component build number when Encrypt is called. This configuration setting is read-only.

CloseInputStreamAfterProcessing:   Determines whether or not the input stream is closed after processing.

Determines whether or not the input stream set by SetInputStream is closed after processing is complete. The default value is True.

CloseOutputStreamAfterProcessing:   Determines whether or not the output stream is closed after processing.

Determines whether or not the output stream set by SetOutputStream is closed after processing is complete. The default value is True.

LogLevel:   Specifies the level of detail that is logged.

This setting controls the level of detail that is logged through the Status event. Possible values are:

0 (None)No events are logged.
1 (Info - default)Informational events are logged.
2 (Verbose)Detailed data is logged.
3 (Debug)Debug data is logged.
WriteToProgressEvent:   Whether to write output data so it is accessible from inside the progress event.

When set to True this setting allows output data to be obtained from within the Progress event. event.

By default, this config is set to false.

Base Config Settings

BuildInfo:   Information about the product's build.

When queried, this setting will return a string containing information about the product's build.

GUIAvailable:   Whether or not a message loop is available for processing events.

In a GUI-based application, long-running blocking operations may cause the application to stop responding to input until the operation returns. The class will attempt to discover whether or not the application has a message loop and, if one is discovered, it will process events in that message loop during any such blocking operation.

In some non-GUI applications, an invalid message loop may be discovered that will result in errant behavior. In these cases, setting GUIAvailable to false will ensure that the class does not attempt to process external events.

LicenseInfo:   Information about the current license.

When queried, this setting will return a string containing information about the license this instance of a class is using. It will return the following information:

  • Product: The product the license is for.
  • Product Key: The key the license was generated from.
  • License Source: Where the license was found (e.g., RuntimeLicense, License File).
  • License Type: The type of license installed (e.g., Royalty Free, Single Server).
  • Last Valid Build: The last valid build number for which the license will work.
MaskSensitiveData:   Whether sensitive data is masked in log messages.

In certain circumstances it may be beneficial to mask sensitive data, like passwords, in log messages. Set this to true to mask sensitive data. The default is true.

This setting only works on these classes: AS3Receiver, AS3Sender, Atom, Client(3DS), FTP, FTPServer, IMAP, OFTPClient, SSHClient, SCP, Server(3DS), Sexec, SFTP, SFTPServer, SSHServer, TCPClient, TCPServer.

UseDaemonThreads:   Whether threads created by the class are daemon threads.

If set to True (default), when the class creates a thread, the thread's Daemon property will be explicitly set to True. When set to False, the class will not set the Daemon property on the created thread. The default value is True.

UseFIPSCompliantAPI:   Tells the class whether or not to use FIPS certified APIs.

When set to true, the class will utilize the underlying operating system's certified APIs. Java editions, regardless of OS, utilize Bouncy Castle Federal Information Processing Standards (FIPS), while all other Windows editions make use of Microsoft security libraries.

The Java edition requires installation of the FIPS-certified Bouncy Castle library regardless of the target operating system. This can be downloaded from https://www.bouncycastle.org/fips-java/. Only the "Provider" library is needed. The jar file should then be installed in a JRE search path.

The following classes must be imported in the application in which the component will be used:

import java.security.Security; import org.bouncycastle.jcajce.provider.BouncyCastleFipsProvider;

The Bouncy Castle provider must be added as a valid provider and must also be configured to operate in FIPS mode:

System.setProperty("org.bouncycastle.fips.approved_only","true"); Security.addProvider(new BouncyCastleFipsProvider());

When UseFIPSCompliantAPI is true, Secure Sockets Layer (SSL)-enabled classes can optionally be configured to use the Transport Layer Security (TLS) Bouncy Castle library. When SSLProvider is set to sslpAutomatic (default) or sslpInternal, an internal TLS implementation is used, but all cryptographic operations are offloaded to the Bouncy Castle FIPS provider to achieve FIPS-compliant operation. If SSLProvider is set to sslpPlatform, the Bouncy Castle JSSE will be used in place of the internal TLS implementation.

To enable the use of the Bouncy Castle JSSE take the following steps in addition to the steps above. Both the Bouncy Castle FIPS provider and the Bouncy Castle JSSE must be configured to use the Bouncy Castle TLS library in FIPS mode. Obtain the Bouncy Castle TLS library from https://www.bouncycastle.org/fips-java/. The jar file should then be installed in a JRE search path.

The following classes must be imported in the application in which the component will be used:

import java.security.Security; import org.bouncycastle.jcajce.provider.BouncyCastleFipsProvider; //required to use BCJSSE when SSLProvider is set to sslpPlatform import org.bouncycastle.jsse.provider.BouncyCastleJsseProvider;

The Bouncy Castle provider must be added as a valid provider and also must be configured to operate in FIPS mode:

System.setProperty("org.bouncycastle.fips.approved_only","true"); Security.addProvider(new BouncyCastleFipsProvider()); //required to use BCJSSE when SSLProvider is set to sslpPlatform Security.addProvider(new BouncyCastleJsseProvider("fips:BCFIPS")); //optional - configure logging level of BCJSSE Logger.getLogger("org.bouncycastle.jsse").setLevel(java.util.logging.Level.OFF); //configure the class to use BCJSSE component.setSSLProvider(1); //platform component.config("UseFIPSCompliantAPI=true"); Note: TLS 1.3 support requires the Bouncy Castle TLS library version 1.0.14 or later.

FIPS mode can be enabled by setting the UseFIPSCompliantAPI configuration setting to true. This is a static setting that applies to all instances of all classes of the toolkit within the process. It is recommended to enable or disable this setting once before the component has been used to establish a connection. Enabling FIPS while an instance of the component is active and connected may result in unexpected behavior.

For more details, please see the FIPS 140-2 Compliance article.

Note: Enabling FIPS compliance requires a special license; please contact sales@nsoftware.com for details.

UseInternalSecurityAPI:   Whether or not to use the system security libraries or an internal implementation.

When set to false, the class will use the system security libraries by default to perform cryptographic functions where applicable.

Setting this configuration setting to true tells the class to use the internal implementation instead of using the system security libraries.

This setting is set to false by default on all platforms.

Trappable Errors (AESFile Class)

AESFile Errors

105   An invalid parameter was specified.
111   Overwrite is false and the destination already exists.
112   No input was specified.
115   Invalid password.
116   No password was specified.
202   The input file is not valid AESF format.
303   Cannot open file.
304   Cannot write file.
305   Cannot read file.
306   Cannot create file.