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package com.oracle.security.ucrypto;

import java.io.IOException;
import java.util.Arrays;
import java.security.AlgorithmParametersSpi;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.InvalidParameterSpecException;
import javax.crypto.spec.GCMParameterSpec;
import sun.security.util.*;

This class implements the parameter set used with GCM mode which is defined in RFC5084 as follows:
GCMParameters ::= SEQUENCE {
  aes-nonce        OCTET STRING, -- recommended size is 12 octets
  aes-ICVlen       AES-GCM-ICVlen DEFAULT 12 }
where
AES-GCM-ICVlen ::= INTEGER (12 | 13 | 14 | 15 | 16)
NOTE: however, NIST 800-38D also lists 4 (32bit) and 8 (64bit)
as possible AES-GCM-ICVlen values, so we allow all 6 values.
Since:9
/** * This class implements the parameter set used with GCM mode * which is defined in RFC5084 as follows: * * <pre> * GCMParameters ::= SEQUENCE { * aes-nonce OCTET STRING, -- recommended size is 12 octets * aes-ICVlen AES-GCM-ICVlen DEFAULT 12 } * * where * AES-GCM-ICVlen ::= INTEGER (12 | 13 | 14 | 15 | 16) * NOTE: however, NIST 800-38D also lists 4 (32bit) and 8 (64bit) * as possible AES-GCM-ICVlen values, so we allow all 6 values. * </pre> * * @since 9 */
public final class GCMParameters extends AlgorithmParametersSpi { private byte[] iv; // i.e. aes-nonce private int tLen; // i.e. aes-ICVlen, in bytes public GCMParameters() {} private void setValues(byte[] iv, int tLen) throws IOException { if (iv == null) { throw new IOException("IV cannot be null"); } if (tLen != 4 && tLen != 8 && (tLen < 12 || tLen > 16)) { throw new IOException("Unsupported tag length: " + tLen); } this.iv = iv; this.tLen = tLen; } protected byte[] engineGetEncoded() throws IOException { DerOutputStream out = new DerOutputStream(); DerOutputStream bytes = new DerOutputStream(); bytes.putOctetString(iv); bytes.putInteger(tLen); out.write(DerValue.tag_Sequence, bytes); return out.toByteArray(); } protected byte[] engineGetEncoded(String format) throws IOException { // ignore format for now return engineGetEncoded(); } protected <T extends AlgorithmParameterSpec> T engineGetParameterSpec(Class<T> paramSpec) throws InvalidParameterSpecException { if (GCMParameterSpec.class.isAssignableFrom(paramSpec)) { return paramSpec.cast(new GCMParameterSpec(tLen*8, iv.clone())); } else { throw new InvalidParameterSpecException ("Inappropriate parameter specification. Received " + paramSpec.getClass().getName()); } } protected void engineInit(AlgorithmParameterSpec paramSpec) throws InvalidParameterSpecException { if (!(paramSpec instanceof GCMParameterSpec)) { throw new InvalidParameterSpecException ("Inappropriate parameter specification. Received " + paramSpec.getClass().getName()); } GCMParameterSpec gcmSpec = (GCMParameterSpec) paramSpec; try { setValues(gcmSpec.getIV(), gcmSpec.getTLen()/8); } catch (IOException ioe) { throw new InvalidParameterSpecException(ioe.getMessage()); } } protected void engineInit(byte[] encoded) throws IOException { DerValue val = new DerValue(encoded); if (val.tag == DerValue.tag_Sequence) { val.data.reset(); setValues(val.data.getOctetString(), val.data.getInteger()); } else { throw new IOException("GCM parameter parsing error: SEQ tag expected." + " Received: " + val.tag); } } protected void engineInit(byte[] encoded, String format) throws IOException { // ignore format for now engineInit(encoded); } protected String engineToString() { return ("IV=" + Arrays.toString(iv) + ", tLen=" + tLen * 8); } }