IExternalSignature

All Known Implementing Classes:

PrivateKeySignature
```
public interface IExternalSignature
```
Interface that needs to be implemented to do the actual signing. For instance: you'll have to implement this interface if you want to sign a PDF using a smart card.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`java.lang.String`	`getDigestAlgorithmName()`	Returns the digest algorithm.
`java.lang.String`	`getSignatureAlgorithmName()`	Returns the signature algorithm used for signing, disregarding the digest function.
`ISignatureMechanismParams`	`getSignatureMechanismParameters()`	Return the algorithm parameters that need to be encoded together with the signature mechanism identifier.
`byte[]`	`sign(byte[] message)`	Signs the given message using the encryption algorithm in combination with the hash algorithm.

- Method Detail
  - getDigestAlgorithmName
```
java.lang.String getDigestAlgorithmName()
```
    Returns the digest algorithm.
    
    Returns:
    
    The digest algorithm (e.g. "SHA-1", "SHA-256,...").
  - getSignatureAlgorithmName
```
java.lang.String getSignatureAlgorithmName()
```
    Returns the signature algorithm used for signing, disregarding the digest function.
    
    Returns:
    
    The signature algorithm ("RSA", "DSA", "ECDSA", "Ed25519" or "Ed448").
  - getSignatureMechanismParameters
```
ISignatureMechanismParams getSignatureMechanismParameters()
```
    Return the algorithm parameters that need to be encoded together with the signature mechanism identifier. If there are no parameters, return `null`. A non-null value is required for RSASSA-PSS; see RSASSAPSSMechanismParams.
    
    Returns:
    
    algorithm parameters
  - sign
```
byte[] sign(byte[] message)
     throws java.security.GeneralSecurityException
```
    Signs the given message using the encryption algorithm in combination with the hash algorithm.
    
    Parameters:
    
    message - The message you want to be hashed and signed.
    
    Returns:
    
    A signed message digest.
    
    Throws:
    
    java.security.GeneralSecurityException - when requested cryptographic algorithm or security provider is not available