com.itextpdf.signatures

Interface 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.

Author:

Paulo Soares

Method Summary

Modifier and Type	Method and Description
String	getDigestAlgorithmName() Returns the digest algorithm.
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

String getDigestAlgorithmName()

Returns the digest algorithm.

Returns:

The digest algorithm (e.g. "SHA-1", "SHA-256,...").

getSignatureAlgorithmName

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 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:

GeneralSecurityException - when requested cryptographic algorithm or security provider is not available