com.itextpdf.signatures

Class DigestAlgorithms

java.lang.Object

com.itextpdf.signatures.DigestAlgorithms

public class DigestAlgorithms
extends Object

Class that contains a map with the different message digest algorithms.

Field Summary

Fields

Modifier and Type	Field and Description
static String	RIPEMD160 Algorithm available for signatures since PDF 1.7.
static String	SHA1 Algorithm available for signatures since PDF 1.3.
static String	SHA256 Algorithm available for signatures since PDF 1.6.
static String	SHA384 Algorithm available for signatures since PDF 1.7.
static String	SHA512 Algorithm available for signatures since PDF 1.7.

Constructor Summary

Constructors

Constructor and Description
DigestAlgorithms()

Method Summary

Modifier and Type	Method and Description
static byte[]	digest(InputStream data, MessageDigest messageDigest) Create a digest based on the inputstream.
static byte[]	digest(InputStream data, String hashAlgorithm, String provider) Creates a hash using a specific digest algorithm and a provider.
static String	getAllowedDigest(String name) Returns the id of a digest algorithms that is allowed in PDF, or null if it isn't allowed.
static String	getDigest(String oid) Gets the digest name for a certain id
static MessageDigest	getMessageDigest(String hashAlgorithm, String provider) Creates a MessageDigest object that can be used to create a hash.
static MessageDigest	getMessageDigestFromOid(String digestOid, String provider) Get a digest algorithm.
static String	normalizeDigestName(String algo) Normalize the digest name.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

SHA1

public static final String SHA1

Algorithm available for signatures since PDF 1.3.

See Also:

Constant Field Values

SHA256

public static final String SHA256

Algorithm available for signatures since PDF 1.6.

See Also:

Constant Field Values

SHA384

public static final String SHA384

Algorithm available for signatures since PDF 1.7.

See Also:

Constant Field Values

SHA512

public static final String SHA512

Algorithm available for signatures since PDF 1.7.

See Also:

Constant Field Values

RIPEMD160

public static final String RIPEMD160

Algorithm available for signatures since PDF 1.7.

See Also:

Constant Field Values

Constructor Detail

DigestAlgorithms

public DigestAlgorithms()

Method Detail

getMessageDigestFromOid

public static MessageDigest getMessageDigestFromOid(String digestOid,
                                                    String provider)
                                             throws NoSuchAlgorithmException,
                                                    NoSuchProviderException

Get a digest algorithm.

Parameters:

digestOid - oid of the digest algorithm

provider - the provider you want to use to create the hash

Returns:

MessageDigest object

Throws:

NoSuchAlgorithmException - thrown when a particular cryptographic algorithm is requested but is not available in the environment

NoSuchProviderException - thrown when a particular security provider is requested but is not available in the environment

getMessageDigest

public static MessageDigest getMessageDigest(String hashAlgorithm,
                                             String provider)
                                      throws NoSuchAlgorithmException,
                                             NoSuchProviderException

Creates a MessageDigest object that can be used to create a hash.

Parameters:

hashAlgorithm - the algorithm you want to use to create a hash

provider - the provider you want to use to create the hash

Returns:

a MessageDigest object

Throws:

NoSuchAlgorithmException - thrown when a particular cryptographic algorithm is requested but is not available in the environment

NoSuchProviderException - thrown when a particular security provider is requested but is not available in the environment

digest

public static byte[] digest(InputStream data,
                            String hashAlgorithm,
                            String provider)
                     throws GeneralSecurityException,
                            IOException

Creates a hash using a specific digest algorithm and a provider.

Parameters:

data - the message of which you want to create a hash

hashAlgorithm - the algorithm used to create the hash

provider - the provider used to create the hash

Returns:

the hash

Throws:

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

IOException - signals that an I/O exception has occurred

digest

public static byte[] digest(InputStream data,
                            MessageDigest messageDigest)
                     throws IOException

Create a digest based on the inputstream.

Parameters:

data - data to be digested

messageDigest - algorithm to be used

Returns:

digest of the data

Throws:

IOException - signals that an I/O exception has occurred

getDigest

public static String getDigest(String oid)

Gets the digest name for a certain id

Parameters:

oid - an id (for instance "1.2.840.113549.2.5")

Returns:

a digest name (for instance "MD5")

normalizeDigestName

public static String normalizeDigestName(String algo)

Normalize the digest name.

Parameters:

algo - the name to be normalized

Returns:

normalized name

getAllowedDigest

public static String getAllowedDigest(String name)

Returns the id of a digest algorithms that is allowed in PDF, or null if it isn't allowed.

Parameters:

name - The name of the digest algorithm.

Returns:

An oid.