ITSAClient

All Known Implementing Classes:

TSAClientBouncyCastle
```
public interface ITSAClient
```
Time Stamp Authority client (caller) interface.
Interface used by the PdfPKCS7 digital signature builder to call Time Stamp Authority providing RFC 3161 compliant time stamp token.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`java.security.MessageDigest`	`getMessageDigest()`	Returns the `MessageDigest` to digest the data imprint
`byte[]`	`getTimeStampToken(byte[] imprint)`	Returns RFC 3161 timeStampToken.
`int`	`getTokenSizeEstimate()`	Get the time stamp estimated token size.

- Method Detail
  - getTokenSizeEstimate
```
int getTokenSizeEstimate()
```
    Get the time stamp estimated token size. Implementation must return value large enough to accommodate the entire token returned by getTimeStampToken(byte[]) prior to actual getTimeStampToken(byte[]) call.
    
    Returns:
    
    an estimate of the token size
  - getMessageDigest
```
java.security.MessageDigest getMessageDigest()
                                      throws java.security.GeneralSecurityException
```
    Returns the MessageDigest to digest the data imprint
    
    Returns:
    
    The MessageDigest object.
    
    Throws:
    
    java.security.GeneralSecurityException - the general security exception
  - getTimeStampToken
```
byte[] getTimeStampToken(byte[] imprint)
                  throws java.lang.Exception
```
    Returns RFC 3161 timeStampToken.
    
    Parameters:
    
    imprint - byte[] - data imprint to be time-stamped
    
    Returns:
    
    byte[] - encoded, TSA signed data of the timeStampToken
    
    Throws:
    
    java.lang.Exception - - TSA request failed