Class DigestAlgorithms

java.lang.Object

com.itextpdf.text.pdf.security.DigestAlgorithms

public class DigestAlgorithms
extends Object

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

Field Summary

Fields

Modifier and Type	Field	Description
private static final HashMap<String,String>	allowedDigests	Maps the name of a digest algorithm with its ID.
private static final HashMap<String,String>	digestNames	Maps the digest IDs with the human-readable name of the digest algorithm.
private static final HashMap<String,String>	fixNames	Maps digest algorithm that are unknown by the JDKs MessageDigest object to a known one.
static final String	RIPEMD160	Algorithm available for signatures since PDF 1.7
static final String	SHA1	Algorithm available for signatures since PDF 1.3
static final String	SHA256	Algorithm available for signatures since PDF 1.6
static final String	SHA384	Algorithm available for signatures since PDF 1.7
static final String	SHA512	Algorithm available for signatures since PDF 1.7

Constructor Summary

Constructors

Constructor	Description
DigestAlgorithms()

Method Summary

Modifier and Type	Method	Description
static byte[]	digest(InputStream data, String hashAlgorithm, String provider)	Creates a hash using a specific digest algorithm and a provider.
static byte[]	digest(InputStream data, MessageDigest messageDigest)
static String	getAllowedDigests(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)
static String	normalizeDigestName(String algo)

Methods inherited from class Object

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

Field Details

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

digestNames

private static final HashMap<String,String> digestNames

Maps the digest IDs with the human-readable name of the digest algorithm.

fixNames

private static final HashMap<String,String> fixNames

Maps digest algorithm that are unknown by the JDKs MessageDigest object to a known one.

allowedDigests

private static final HashMap<String,String> allowedDigests

Maps the name of a digest algorithm with its ID.

Constructor Details

DigestAlgorithms

public DigestAlgorithms()

Method Details

getMessageDigestFromOid

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

Throws:

NoSuchAlgorithmException

NoSuchProviderException

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

NoSuchProviderException

GeneralSecurityException

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

IOException

digest

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

Throws:

GeneralSecurityException

IOException

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)

getAllowedDigests

public static String getAllowedDigests(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