keystore/java/android/security/EcIesParameterSpec.java - LeafOS-Project/android_frameworks_base - Gitiles

 package android.security;

 import android.annotation.IntDef;
 import android.annotation.NonNull;
 import android.annotation.Nullable;

 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.security.spec.AlgorithmParameterSpec;

 import javax.crypto.Cipher;
 import javax.crypto.Mac;

 /**
  * {@link AlgorithmParameterSpec} for ECIES (Integrated Encryption Scheme using Elliptic Curve
  * cryptography) based on {@code ISO/IEC 18033-2}.
  *
  * <p>ECIES is a hybrid authenticated encryption scheme. Encryption is performed using an Elliptic
  * Curve (EC) public key. The resulting ciphertext can be decrypted only using the corresponding EC
  * private key. The scheme is called hybrid because the EC key is only used to securely encapsulate
  * symmetric key material. Encryption of plaintext and authentication of the corresponding
  * ciphertext is performed using symmetric cryptography.
  *
  * <p>Encryption using ECIES consists of two stages:
  * <ol>
  * <li>Key Encapsulation Mechanism (KEM) randomly generates symmetric key material and securely
  * encapsulates it in the output so that it can be extracted by the KEM when decrypting.
  * Encapsulated key material is represented in the output as an EC point.</li>
  * <li>The above symmetric key material is used by Data Encapsulation Mechanism (DEM) to encrypt the
  * provided plaintext and authenticate the ciphertext. The resulting authenticated ciphertext is
  * then output. When decrypting, the DEM first authenticates the ciphertext and, only if it
  * authenticates, decrypts the ciphertext and outputs the plaintext.</li>
  * </ol>
  *
  * <p>Details of KEM:
  * <ul>
  * <li>Only curves with cofactor of {@code 1} are supported.</li>
  * <li>{@code CheckMode}, {@code OldCofactorMode}, {@code CofactorMode}, and {@code SingleHashMode}
  * are {@code 0}.
  * <li>Point format is specified by {@link #getKemPointFormat()}.</li>
  * <li>KDF algorithm is specified by {@link #getKemKdfAlgorithm()}.</li>
  * </ul>
  *
  * <p>Details of DEM:
  * <ul>
  * <li>Only DEM1-like mechanism is supported, with its symmetric cipher (SC) specified by
  * {@link #getDemCipherTransformation()} (e.g., {@code AES/CBC/NoPadding} for standard DEM1) and
  * MAC algorithm specified by {@link #getDemMacAlgorithm()} (e.g., {@code HmacSHA1} for standard
  * DEM1).</li>
  * </ul>
  */
 public class EcIesParameterSpec implements AlgorithmParameterSpec {

     @Retention(RetentionPolicy.SOURCE)
     @IntDef({
         PointFormat.UNSPECIFIED,
         PointFormat.UNCOMPRESSED,
         PointFormat.COMPRESSED,
         })
     public @interface PointFormatEnum {}

     /**
      * Wire format of the EC point.
      */
     public static abstract class PointFormat {

         private PointFormat() {}

         /** Unspecified point format. */
         public static final int UNSPECIFIED = -1;

         /**
          * Uncompressed point format: both coordinates are stored separately.
          *
          * <p>The wire format is byte {@code 0x04} followed by binary representation of the
          * {@code x} coordinate followed by binary representation of the {@code y} coordinate. See
          * {@code ISO 18033-2} section {@code 5.4.3}.
          */
         public static final int UNCOMPRESSED = 0;

         /**
          * Compressed point format: only one coordinate is stored.
          *
          * <p>The wire format is byte {@code 0x02} or {@code 0x03} (depending on the value of the
          * stored coordinate) followed by the binary representation of the {@code x} coordinate.
          * See {@code ISO 18033-2} section {@code 5.4.3}.
          */
         public static final int COMPRESSED = 1;
     }

     /**
      * Default parameter spec: compressed point format, {@code HKDFwithSHA256}, DEM uses 128-bit AES
      * GCM.
      */
     public static final EcIesParameterSpec DEFAULT = new EcIesParameterSpec(
             PointFormat.COMPRESSED,
             "HKDFwithSHA256",
             "AES/GCM/NoPadding",
             128,
             null,
             0);

     private final @PointFormatEnum int mKemPointFormat;
     private final String mKemKdfAlgorithm;
     private final String mDemCipherTransformation;
     private final int mDemCipherKeySize;
     private final String mDemMacAlgorithm;
     private final int mDemMacKeySize;

     private EcIesParameterSpec(
             @PointFormatEnum int kemPointFormat,
             String kemKdfAlgorithm,
             String demCipherTransformation,
             int demCipherKeySize,
             String demMacAlgorithm,
             int demMacKeySize) {
         mKemPointFormat = kemPointFormat;
         mKemKdfAlgorithm = kemKdfAlgorithm;
         mDemCipherTransformation = demCipherTransformation;
         mDemCipherKeySize = demCipherKeySize;
         mDemMacAlgorithm = demMacAlgorithm;
         mDemMacKeySize = demMacKeySize;
     }

     /**
      * Returns KEM EC point wire format or {@link PointFormat#UNSPECIFIED} if not specified.
      */
     public @PointFormatEnum int getKemPointFormat() {
         return mKemPointFormat;
     }

     /**
      * Returns KEM KDF algorithm (e.g., {@code HKDFwithSHA256} or {@code KDF1withSHA1}) or
      * {@code null} if not specified.
      */
     @Nullable
     public String getKemKdfAlgorithm() {
         return mKemKdfAlgorithm;
     }

     /**
      * Returns DEM {@link Cipher} transformation (e.g., {@code AES/GCM/NoPadding} or
      * {@code AES/CBC/PKCS7Padding}) or {@code null} if not specified.
      *
      * @see Cipher#getInstance(String)
      * @see #getDemCipherKeySize()
      */
     @Nullable
     public String getDemCipherTransformation() {
         return mDemCipherTransformation;
     }

     /**
      * Returns DEM {@link Cipher} key size in bits.
      *
      * @see #getDemCipherTransformation()
      */
     public int getDemCipherKeySize() {
         return mDemCipherKeySize;
     }

     /**
      * Returns DEM {@link Mac} algorithm (e.g., {@code HmacSHA256} or {@code HmacSHA1}) or
      * {@code null} if not specified.
      *
      * @see Mac#getInstance(String)
      * @see #getDemMacKeySize()
      */
     @Nullable
     public String getDemMacAlgorithm() {
         return mDemMacAlgorithm;
     }

     /**
      * Returns DEM {@link Mac} key size in bits.
      *
      * @see #getDemCipherTransformation()
      */
     public int getDemMacKeySize() {
         return mDemMacKeySize;
     }

     /**
      * Builder of {@link EcIesParameterSpec}.
      */
     public static class Builder {
         private @PointFormatEnum int mKemPointFormat = PointFormat.UNSPECIFIED;
         private String mKemKdfAlgorithm;
         private String mDemCipherTransformation;
         private int mDemCipherKeySize = 128;
         private String mDemMacAlgorithm;
         private int mDemMacKeySize = -1;

         /**
          * Sets KEM EC point wire format.
          */
         public Builder setKemPointFormat(@PointFormatEnum int pointFormat) {
             mKemPointFormat = pointFormat;
             return this;
         }

         /**
          * Sets KEM KDF algorithm. For example, {@code HKDFwithSHA256}, {@code KDF2withSHA256}, or
          * {@code KDF1withSHA1}.
          */
         @NonNull
         public Builder setKemKdfAlgorithm(@Nullable String algorithm) {
             mKemKdfAlgorithm = algorithm;
             return this;
         }

         /**
          * Sets DEM {@link Cipher} transformation. For example, {@code AES/GCM/NoPadding},
          * {@code AES/CBC/PKCS7Padding} or {@code AES/CTR/NoPadding}.
          *
          * @see Cipher#getInstance(String)
          */
         @NonNull
         public Builder setDemCipherTransformation(@Nullable String transformation) {
             mDemCipherTransformation = transformation;
             return this;
         }

         /**
          * Returns DEM {@link Cipher} key size in bits.
          *
          * <p>The default value is {@code 128} bits.
          *
          * @see #setDemCipherTransformation(String)
          */
         @NonNull
         public Builder setDemCipherKeySize(int sizeBits) {
             mDemCipherKeySize = sizeBits;
             return this;
         }

         /**
          * Sets DEM {@link Mac} algorithm. For example, {@code HmacSHA256} or {@code HmacSHA1}.
          *
          * @see Mac#getInstance(String)
          */
         @NonNull
         public Builder setDemMacAlgorithm(@Nullable String algorithm) {
             mDemMacAlgorithm = algorithm;
             return this;
         }

         /**
          * Sets DEM {@link Mac} key size in bits.
          *
          * <p>By default, {@code Mac} key size is the same as the {@code Cipher} key size.
          *
          * @see #setDemCipherKeySize(int)
          */
         @NonNull
         public Builder setDemMacKeySize(int sizeBits) {
             mDemMacKeySize = sizeBits;
             return this;
         }

         /**
          * Returns a new {@link EcIesParameterSpec} based on the current state of this builder.
          */
         @NonNull
         public EcIesParameterSpec build() {
             int demMacKeySize = (mDemMacKeySize != -1) ? mDemMacKeySize : mDemCipherKeySize;
             return new EcIesParameterSpec(
                     mKemPointFormat,
                     mKemKdfAlgorithm,
                     mDemCipherTransformation,
                     mDemCipherKeySize,
                     mDemMacAlgorithm,
                     demMacKeySize
                     );
         }
     }
 }
	package android.security;

	import android.annotation.IntDef;
	import android.annotation.NonNull;
	import android.annotation.Nullable;

	import java.lang.annotation.Retention;
	import java.lang.annotation.RetentionPolicy;
	import java.security.spec.AlgorithmParameterSpec;

	import javax.crypto.Cipher;
	import javax.crypto.Mac;

	/**
	* {@link AlgorithmParameterSpec} for ECIES (Integrated Encryption Scheme using Elliptic Curve
	* cryptography) based on {@code ISO/IEC 18033-2}.
	*
	* <p>ECIES is a hybrid authenticated encryption scheme. Encryption is performed using an Elliptic
	* Curve (EC) public key. The resulting ciphertext can be decrypted only using the corresponding EC
	* private key. The scheme is called hybrid because the EC key is only used to securely encapsulate
	* symmetric key material. Encryption of plaintext and authentication of the corresponding
	* ciphertext is performed using symmetric cryptography.
	*
	* <p>Encryption using ECIES consists of two stages:
	* <ol>
	* <li>Key Encapsulation Mechanism (KEM) randomly generates symmetric key material and securely
	* encapsulates it in the output so that it can be extracted by the KEM when decrypting.
	* Encapsulated key material is represented in the output as an EC point.</li>
	* <li>The above symmetric key material is used by Data Encapsulation Mechanism (DEM) to encrypt the
	* provided plaintext and authenticate the ciphertext. The resulting authenticated ciphertext is
	* then output. When decrypting, the DEM first authenticates the ciphertext and, only if it
	* authenticates, decrypts the ciphertext and outputs the plaintext.</li>
	* </ol>
	*
	* <p>Details of KEM:
	* <ul>
	* <li>Only curves with cofactor of {@code 1} are supported.</li>
	* <li>{@code CheckMode}, {@code OldCofactorMode}, {@code CofactorMode}, and {@code SingleHashMode}
	* are {@code 0}.
	* <li>Point format is specified by {@link #getKemPointFormat()}.</li>
	* <li>KDF algorithm is specified by {@link #getKemKdfAlgorithm()}.</li>
	* </ul>
	*
	* <p>Details of DEM:
	* <ul>
	* <li>Only DEM1-like mechanism is supported, with its symmetric cipher (SC) specified by
	* {@link #getDemCipherTransformation()} (e.g., {@code AES/CBC/NoPadding} for standard DEM1) and
	* MAC algorithm specified by {@link #getDemMacAlgorithm()} (e.g., {@code HmacSHA1} for standard
	* DEM1).</li>
	* </ul>
	*/
	public class EcIesParameterSpec implements AlgorithmParameterSpec {

	@Retention(RetentionPolicy.SOURCE)
	@IntDef({
	PointFormat.UNSPECIFIED,
	PointFormat.UNCOMPRESSED,
	PointFormat.COMPRESSED,
	})
	public @interface PointFormatEnum {}

	/**
	* Wire format of the EC point.
	*/
	public static abstract class PointFormat {

	private PointFormat() {}

	/** Unspecified point format. */
	public static final int UNSPECIFIED = -1;

	/**
	* Uncompressed point format: both coordinates are stored separately.
	*
	* <p>The wire format is byte {@code 0x04} followed by binary representation of the
	* {@code x} coordinate followed by binary representation of the {@code y} coordinate. See
	* {@code ISO 18033-2} section {@code 5.4.3}.
	*/
	public static final int UNCOMPRESSED = 0;

	/**
	* Compressed point format: only one coordinate is stored.
	*
	* <p>The wire format is byte {@code 0x02} or {@code 0x03} (depending on the value of the
	* stored coordinate) followed by the binary representation of the {@code x} coordinate.
	* See {@code ISO 18033-2} section {@code 5.4.3}.
	*/
	public static final int COMPRESSED = 1;
	}

	/**
	* Default parameter spec: compressed point format, {@code HKDFwithSHA256}, DEM uses 128-bit AES
	* GCM.
	*/
	public static final EcIesParameterSpec DEFAULT = new EcIesParameterSpec(
	PointFormat.COMPRESSED,
	"HKDFwithSHA256",
	"AES/GCM/NoPadding",
	128,
	null,
	0);

	private final @PointFormatEnum int mKemPointFormat;
	private final String mKemKdfAlgorithm;
	private final String mDemCipherTransformation;
	private final int mDemCipherKeySize;
	private final String mDemMacAlgorithm;
	private final int mDemMacKeySize;

	private EcIesParameterSpec(
	@PointFormatEnum int kemPointFormat,
	String kemKdfAlgorithm,
	String demCipherTransformation,
	int demCipherKeySize,
	String demMacAlgorithm,
	int demMacKeySize) {
	mKemPointFormat = kemPointFormat;
	mKemKdfAlgorithm = kemKdfAlgorithm;
	mDemCipherTransformation = demCipherTransformation;
	mDemCipherKeySize = demCipherKeySize;
	mDemMacAlgorithm = demMacAlgorithm;
	mDemMacKeySize = demMacKeySize;
	}

	/**
	* Returns KEM EC point wire format or {@link PointFormat#UNSPECIFIED} if not specified.
	*/
	public @PointFormatEnum int getKemPointFormat() {
	return mKemPointFormat;
	}

	/**
	* Returns KEM KDF algorithm (e.g., {@code HKDFwithSHA256} or {@code KDF1withSHA1}) or
	* {@code null} if not specified.
	*/
	@Nullable
	public String getKemKdfAlgorithm() {
	return mKemKdfAlgorithm;
	}

	/**
	* Returns DEM {@link Cipher} transformation (e.g., {@code AES/GCM/NoPadding} or
	* {@code AES/CBC/PKCS7Padding}) or {@code null} if not specified.
	*
	* @see Cipher#getInstance(String)
	* @see #getDemCipherKeySize()
	*/
	@Nullable
	public String getDemCipherTransformation() {
	return mDemCipherTransformation;
	}

	/**
	* Returns DEM {@link Cipher} key size in bits.
	*
	* @see #getDemCipherTransformation()
	*/
	public int getDemCipherKeySize() {
	return mDemCipherKeySize;
	}

	/**
	* Returns DEM {@link Mac} algorithm (e.g., {@code HmacSHA256} or {@code HmacSHA1}) or
	* {@code null} if not specified.
	*
	* @see Mac#getInstance(String)
	* @see #getDemMacKeySize()
	*/
	@Nullable
	public String getDemMacAlgorithm() {
	return mDemMacAlgorithm;
	}

	/**
	* Returns DEM {@link Mac} key size in bits.
	*
	* @see #getDemCipherTransformation()
	*/
	public int getDemMacKeySize() {
	return mDemMacKeySize;
	}

	/**
	* Builder of {@link EcIesParameterSpec}.
	*/
	public static class Builder {
	private @PointFormatEnum int mKemPointFormat = PointFormat.UNSPECIFIED;
	private String mKemKdfAlgorithm;
	private String mDemCipherTransformation;
	private int mDemCipherKeySize = 128;
	private String mDemMacAlgorithm;
	private int mDemMacKeySize = -1;

	/**
	* Sets KEM EC point wire format.
	*/
	public Builder setKemPointFormat(@PointFormatEnum int pointFormat) {
	mKemPointFormat = pointFormat;
	return this;
	}

	/**
	* Sets KEM KDF algorithm. For example, {@code HKDFwithSHA256}, {@code KDF2withSHA256}, or
	* {@code KDF1withSHA1}.
	*/
	@NonNull
	public Builder setKemKdfAlgorithm(@Nullable String algorithm) {
	mKemKdfAlgorithm = algorithm;
	return this;
	}

	/**
	* Sets DEM {@link Cipher} transformation. For example, {@code AES/GCM/NoPadding},
	* {@code AES/CBC/PKCS7Padding} or {@code AES/CTR/NoPadding}.
	*
	* @see Cipher#getInstance(String)
	*/
	@NonNull
	public Builder setDemCipherTransformation(@Nullable String transformation) {
	mDemCipherTransformation = transformation;
	return this;
	}

	/**
	* Returns DEM {@link Cipher} key size in bits.
	*
	* <p>The default value is {@code 128} bits.
	*
	* @see #setDemCipherTransformation(String)
	*/
	@NonNull
	public Builder setDemCipherKeySize(int sizeBits) {
	mDemCipherKeySize = sizeBits;
	return this;
	}

	/**
	* Sets DEM {@link Mac} algorithm. For example, {@code HmacSHA256} or {@code HmacSHA1}.
	*
	* @see Mac#getInstance(String)
	*/
	@NonNull
	public Builder setDemMacAlgorithm(@Nullable String algorithm) {
	mDemMacAlgorithm = algorithm;
	return this;
	}

	/**
	* Sets DEM {@link Mac} key size in bits.
	*
	* <p>By default, {@code Mac} key size is the same as the {@code Cipher} key size.
	*
	* @see #setDemCipherKeySize(int)
	*/
	@NonNull
	public Builder setDemMacKeySize(int sizeBits) {
	mDemMacKeySize = sizeBits;
	return this;
	}

	/**
	* Returns a new {@link EcIesParameterSpec} based on the current state of this builder.
	*/
	@NonNull
	public EcIesParameterSpec build() {
	int demMacKeySize = (mDemMacKeySize != -1) ? mDemMacKeySize : mDemCipherKeySize;
	return new EcIesParameterSpec(
	mKemPointFormat,
	mKemKdfAlgorithm,
	mDemCipherTransformation,
	mDemCipherKeySize,
	mDemMacAlgorithm,
	demMacKeySize
	);
	}
	}
	}