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package com.sun.crypto.provider;

import java.math.BigInteger;
import java.io.*;
import sun.security.util.*;
import sun.security.x509.*;
import java.security.AlgorithmParametersSpi;
import java.security.NoSuchAlgorithmException;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.InvalidParameterSpecException;
import java.security.spec.MGF1ParameterSpec;
import javax.crypto.spec.PSource;
import javax.crypto.spec.OAEPParameterSpec;

This class implements the OAEP parameters used with the RSA algorithm in OAEP padding. Here is its ASN.1 definition: RSAES-OAEP-params ::= SEQUENCE { hashAlgorithm [0] HashAlgorithm DEFAULT sha1, maskGenAlgorithm [1] MaskGenAlgorithm DEFAULT mgf1SHA1, pSourceAlgorithm [2] PSourceAlgorithm DEFAULT pSpecifiedEmpty }
Author:Valerie Peng
/** * This class implements the OAEP parameters used with the RSA * algorithm in OAEP padding. Here is its ASN.1 definition: * RSAES-OAEP-params ::= SEQUENCE { * hashAlgorithm [0] HashAlgorithm DEFAULT sha1, * maskGenAlgorithm [1] MaskGenAlgorithm DEFAULT mgf1SHA1, * pSourceAlgorithm [2] PSourceAlgorithm DEFAULT pSpecifiedEmpty * } * * @author Valerie Peng * */
public final class OAEPParameters extends AlgorithmParametersSpi { private String mdName; private MGF1ParameterSpec mgfSpec; private byte[] p; private static ObjectIdentifier OID_MGF1; private static ObjectIdentifier OID_PSpecified; static { try { OID_MGF1 = new ObjectIdentifier(new int[] {1,2,840,113549,1,1,8}); } catch (IOException ioe) { // should not happen OID_MGF1 = null; } try { OID_PSpecified = new ObjectIdentifier(new int[] {1,2,840,113549,1,1,9}); } catch (IOException ioe) { // should not happen OID_PSpecified = null; } } public OAEPParameters() { } protected void engineInit(AlgorithmParameterSpec paramSpec) throws InvalidParameterSpecException { if (!(paramSpec instanceof OAEPParameterSpec)) { throw new InvalidParameterSpecException ("Inappropriate parameter specification"); } OAEPParameterSpec spec = (OAEPParameterSpec) paramSpec; mdName = spec.getDigestAlgorithm(); String mgfName = spec.getMGFAlgorithm(); if (!mgfName.equalsIgnoreCase("MGF1")) { throw new InvalidParameterSpecException("Unsupported mgf " + mgfName + "; MGF1 only"); } AlgorithmParameterSpec mgfSpec = spec.getMGFParameters(); if (!(mgfSpec instanceof MGF1ParameterSpec)) { throw new InvalidParameterSpecException("Inappropriate mgf " + "parameters; non-null MGF1ParameterSpec only"); } this.mgfSpec = (MGF1ParameterSpec) mgfSpec; PSource pSrc = spec.getPSource(); if (pSrc.getAlgorithm().equals("PSpecified")) { p = ((PSource.PSpecified) pSrc).getValue(); } else { throw new InvalidParameterSpecException("Unsupported pSource " + pSrc.getAlgorithm() + "; PSpecified only"); } } protected void engineInit(byte[] encoded) throws IOException { DerInputStream der = new DerInputStream(encoded); mdName = "SHA-1"; mgfSpec = MGF1ParameterSpec.SHA1; p = new byte[0]; DerValue[] datum = der.getSequence(3); for (int i=0; i<datum.length; i++) { DerValue data = datum[i]; if (data.isContextSpecific((byte) 0x00)) { // hash algid mdName = AlgorithmId.parse (data.data.getDerValue()).getName(); } else if (data.isContextSpecific((byte) 0x01)) { // mgf algid AlgorithmId val = AlgorithmId.parse(data.data.getDerValue()); if (!val.getOID().equals(OID_MGF1)) { throw new IOException("Only MGF1 mgf is supported"); } AlgorithmId params = AlgorithmId.parse( new DerValue(val.getEncodedParams())); String mgfDigestName = params.getName(); if (mgfDigestName.equals("SHA-1")) { mgfSpec = MGF1ParameterSpec.SHA1; } else if (mgfDigestName.equals("SHA-224")) { mgfSpec = MGF1ParameterSpec.SHA224; } else if (mgfDigestName.equals("SHA-256")) { mgfSpec = MGF1ParameterSpec.SHA256; } else if (mgfDigestName.equals("SHA-384")) { mgfSpec = MGF1ParameterSpec.SHA384; } else if (mgfDigestName.equals("SHA-512")) { mgfSpec = MGF1ParameterSpec.SHA512; } else if (mgfDigestName.equals("SHA-512/224")) { mgfSpec = MGF1ParameterSpec.SHA512_224; } else if (mgfDigestName.equals("SHA-512/256")) { mgfSpec = MGF1ParameterSpec.SHA512_256; } else { throw new IOException( "Unrecognized message digest algorithm"); } } else if (data.isContextSpecific((byte) 0x02)) { // pSource algid AlgorithmId val = AlgorithmId.parse(data.data.getDerValue()); if (!val.getOID().equals(OID_PSpecified)) { throw new IOException("Wrong OID for pSpecified"); } DerInputStream dis = new DerInputStream(val.getEncodedParams()); p = dis.getOctetString(); if (dis.available() != 0) { throw new IOException("Extra data for pSpecified"); } } else { throw new IOException("Invalid encoded OAEPParameters"); } } } protected void engineInit(byte[] encoded, String decodingMethod) throws IOException { if ((decodingMethod != null) && (!decodingMethod.equalsIgnoreCase("ASN.1"))) { throw new IllegalArgumentException("Only support ASN.1 format"); } engineInit(encoded); } protected <T extends AlgorithmParameterSpec> T engineGetParameterSpec(Class<T> paramSpec) throws InvalidParameterSpecException { if (OAEPParameterSpec.class.isAssignableFrom(paramSpec)) { return paramSpec.cast( new OAEPParameterSpec(mdName, "MGF1", mgfSpec, new PSource.PSpecified(p))); } else { throw new InvalidParameterSpecException ("Inappropriate parameter specification"); } } protected byte[] engineGetEncoded() throws IOException { DerOutputStream tmp = new DerOutputStream(); DerOutputStream tmp2, tmp3; // MD AlgorithmId mdAlgId; try { mdAlgId = AlgorithmId.get(mdName); } catch (NoSuchAlgorithmException nsae) { throw new IOException("AlgorithmId " + mdName + " impl not found"); } tmp2 = new DerOutputStream(); mdAlgId.derEncode(tmp2); tmp.write(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte)0), tmp2); // MGF tmp2 = new DerOutputStream(); tmp2.putOID(OID_MGF1); AlgorithmId mgfDigestId; try { mgfDigestId = AlgorithmId.get(mgfSpec.getDigestAlgorithm()); } catch (NoSuchAlgorithmException nase) { throw new IOException("AlgorithmId " + mgfSpec.getDigestAlgorithm() + " impl not found"); } mgfDigestId.encode(tmp2); tmp3 = new DerOutputStream(); tmp3.write(DerValue.tag_Sequence, tmp2); tmp.write(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte)1), tmp3); // PSource tmp2 = new DerOutputStream(); tmp2.putOID(OID_PSpecified); tmp2.putOctetString(p); tmp3 = new DerOutputStream(); tmp3.write(DerValue.tag_Sequence, tmp2); tmp.write(DerValue.createTag(DerValue.TAG_CONTEXT, true, (byte)2), tmp3); // Put all together under a SEQUENCE tag DerOutputStream out = new DerOutputStream(); out.write(DerValue.tag_Sequence, tmp); return out.toByteArray(); } protected byte[] engineGetEncoded(String encodingMethod) throws IOException { if ((encodingMethod != null) && (!encodingMethod.equalsIgnoreCase("ASN.1"))) { throw new IllegalArgumentException("Only support ASN.1 format"); } return engineGetEncoded(); } protected String engineToString() { StringBuilder sb = new StringBuilder(); sb.append("MD: " + mdName + "\n"); sb.append("MGF: MGF1" + mgfSpec.getDigestAlgorithm() + "\n"); sb.append("PSource: PSpecified " + (p.length==0? "":Debug.toHexString(new BigInteger(p))) + "\n"); return sb.toString(); } }