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package sun.security.rsa;

import java.io.IOException;
import java.math.BigInteger;

import java.security.*;
import java.security.spec.*;
import java.security.interfaces.*;

import sun.security.util.*;
import sun.security.x509.X509Key;
import sun.security.x509.AlgorithmId;

import static sun.security.rsa.RSAUtil.KeyType;

RSA public key implementation for "RSA", "RSASSA-PSS" algorithms. Note: RSA keys must be at least 512 bits long
Author: Andreas Sterbenz
See Also:
Since: 1.5
/** * RSA public key implementation for "RSA", "RSASSA-PSS" algorithms. * * Note: RSA keys must be at least 512 bits long * * @see RSAPrivateCrtKeyImpl * @see RSAPrivateKeyImpl * @see RSAKeyFactory * * @since 1.5 * @author Andreas Sterbenz */
public final class RSAPublicKeyImpl extends X509Key implements RSAPublicKey { private static final long serialVersionUID = 2644735423591199609L; private static final BigInteger THREE = BigInteger.valueOf(3); private BigInteger n; // modulus private BigInteger e; // public exponent // optional parameters associated with this RSA key // specified in the encoding of its AlgorithmId // must be null for "RSA" keys. private AlgorithmParameterSpec keyParams;
Generate a new RSAPublicKey from the specified encoding. Used by SunPKCS11 provider.
/** * Generate a new RSAPublicKey from the specified encoding. * Used by SunPKCS11 provider. */
public static RSAPublicKey newKey(byte[] encoded) throws InvalidKeyException { return new RSAPublicKeyImpl(encoded); }
Generate a new RSAPublicKey from the specified type and components. Used by SunPKCS11 provider.
/** * Generate a new RSAPublicKey from the specified type and components. * Used by SunPKCS11 provider. */
public static RSAPublicKey newKey(KeyType type, AlgorithmParameterSpec params, BigInteger n, BigInteger e) throws InvalidKeyException { AlgorithmId rsaId = RSAUtil.createAlgorithmId(type, params); return new RSAPublicKeyImpl(rsaId, n, e); }
Construct a RSA key from AlgorithmId and its components. Used by RSAKeyFactory and RSAKeyPairGenerator.
/** * Construct a RSA key from AlgorithmId and its components. Used by * RSAKeyFactory and RSAKeyPairGenerator. */
RSAPublicKeyImpl(AlgorithmId rsaId, BigInteger n, BigInteger e) throws InvalidKeyException { RSAKeyFactory.checkRSAProviderKeyLengths(n.bitLength(), e); checkExponentRange(n, e); this.n = n; this.e = e; this.keyParams = RSAUtil.getParamSpec(rsaId); // generate the encoding algid = rsaId; try { DerOutputStream out = new DerOutputStream(); out.putInteger(n); out.putInteger(e); byte[] keyArray = new DerValue(DerValue.tag_Sequence, out.toByteArray()).toByteArray(); setKey(new BitArray(keyArray.length*8, keyArray)); } catch (IOException exc) { // should never occur throw new InvalidKeyException(exc); } }
Construct a key from its encoding. Used by RSAKeyFactory.
/** * Construct a key from its encoding. Used by RSAKeyFactory. */
RSAPublicKeyImpl(byte[] encoded) throws InvalidKeyException { if (encoded == null || encoded.length == 0) { throw new InvalidKeyException("Missing key encoding"); } decode(encoded); // this sets n and e value RSAKeyFactory.checkRSAProviderKeyLengths(n.bitLength(), e); checkExponentRange(n, e); try { // this will check the validity of params this.keyParams = RSAUtil.getParamSpec(algid); } catch (ProviderException e) { throw new InvalidKeyException(e); } } // pkg private utility method for checking RSA modulus and public exponent static void checkExponentRange(BigInteger mod, BigInteger exp) throws InvalidKeyException { // the exponent should be smaller than the modulus if (exp.compareTo(mod) >= 0) { throw new InvalidKeyException("exponent is larger than modulus"); } // the exponent should be at least 3 if (exp.compareTo(THREE) < 0) { throw new InvalidKeyException("exponent is smaller than 3"); } } // see JCA doc @Override public String getAlgorithm() { return algid.getName(); } // see JCA doc @Override public BigInteger getModulus() { return n; } // see JCA doc @Override public BigInteger getPublicExponent() { return e; } // see JCA doc @Override public AlgorithmParameterSpec getParams() { return keyParams; }
Parse the key. Called by X509Key.
/** * Parse the key. Called by X509Key. */
protected void parseKeyBits() throws InvalidKeyException { try { DerInputStream in = new DerInputStream(getKey().toByteArray()); DerValue derValue = in.getDerValue(); if (derValue.tag != DerValue.tag_Sequence) { throw new IOException("Not a SEQUENCE"); } DerInputStream data = derValue.data; n = data.getPositiveBigInteger(); e = data.getPositiveBigInteger(); if (derValue.data.available() != 0) { throw new IOException("Extra data available"); } } catch (IOException e) { throw new InvalidKeyException("Invalid RSA public key", e); } } // return a string representation of this key for debugging @Override public String toString() { return "Sun " + getAlgorithm() + " public key, " + n.bitLength() + " bits" + "\n params: " + keyParams + "\n modulus: " + n + "\n public exponent: " + e; } protected Object writeReplace() throws java.io.ObjectStreamException { return new KeyRep(KeyRep.Type.PUBLIC, getAlgorithm(), getFormat(), getEncoded()); } }