nl.martijndwars.webpush

Class HttpEce

java.lang.Object

nl.martijndwars.webpush.HttpEce

public class HttpEce
extends java.lang.Object

An implementation of Encrypted Content-Encoding for HTTP. The first implementation follows the specification in [1]. The specification later moved from "aesgcm" to "aes128gcm" as content encoding [2]. To remain backwards compatible this library supports both. [1] https://tools.ietf.org/html/draft-ietf-httpbis-encryption-encoding-01 [2] https://tools.ietf.org/html/draft-ietf-httpbis-encryption-encoding-09 TODO: Support multiple records (not needed for Web Push)

Field Summary

Fields

Modifier and Type	Field and Description
static int	KEY_LENGTH
static int	SHA_256_LENGTH
static int	TAG_SIZE
static int	TWO_BYTE_MAX
static java.lang.String	WEB_PUSH_INFO

Constructor Summary

Constructors

Constructor and Description
HttpEce()
HttpEce(java.util.Map<java.lang.String,java.security.KeyPair> keys, java.util.Map<java.lang.String,java.lang.String> labels)

Method Summary

Modifier and Type	Method and Description
protected static byte[]	buildInfo(java.lang.String type, byte[] context) Future versions might require a null-terminated info string?
byte[]	decrypt(byte[] payload, byte[] salt, byte[] key, java.lang.String keyid, Encoding version) Decrypt the payload.
byte[]	decryptRecord(byte[] ciphertext, byte[] key, byte[] nonce, Encoding version)
byte[][]	deriveKeyAndNonce(byte[] salt, byte[] key, java.lang.String keyId, org.bouncycastle.jce.interfaces.ECPublicKey dh, byte[] authSecret, Encoding version, int mode)
byte[]	encrypt(byte[] plaintext, byte[] salt, byte[] privateKey, java.lang.String keyid, org.bouncycastle.jce.interfaces.ECPublicKey dh, byte[] authSecret, Encoding version) Encrypt the given plaintext.
byte[][]	extractSecretAndContext(byte[] key, java.lang.String keyId, org.bouncycastle.jce.interfaces.ECPublicKey dh, byte[] authSecret)
protected static byte[]	hkdfExpand(byte[] ikm, byte[] salt, byte[] info, int length) Convenience method for computing the HMAC Key Derivation Function.
byte[][]	parseHeader(byte[] payload)
byte[]	webpushSecret(java.lang.String keyId, org.bouncycastle.jce.interfaces.ECPublicKey dh, byte[] authSecret, int mode) Combine Shared and Authentication Secrets See https://tools.ietf.org/html/draft-ietf-webpush-encryption-09#section-3.3.

Methods inherited from class java.lang.Object

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

Field Detail

KEY_LENGTH

public static final int KEY_LENGTH

See Also:

Constant Field Values

SHA_256_LENGTH

public static final int SHA_256_LENGTH

See Also:

Constant Field Values

TAG_SIZE

public static final int TAG_SIZE

See Also:

Constant Field Values

TWO_BYTE_MAX

public static final int TWO_BYTE_MAX

See Also:

Constant Field Values

WEB_PUSH_INFO

public static final java.lang.String WEB_PUSH_INFO

See Also:

Constant Field Values

Constructor Detail

HttpEce

public HttpEce()

HttpEce

public HttpEce(java.util.Map<java.lang.String,java.security.KeyPair> keys,
               java.util.Map<java.lang.String,java.lang.String> labels)

Method Detail

encrypt

public byte[] encrypt(byte[] plaintext,
                      byte[] salt,
                      byte[] privateKey,
                      java.lang.String keyid,
                      org.bouncycastle.jce.interfaces.ECPublicKey dh,
                      byte[] authSecret,
                      Encoding version)
               throws java.security.GeneralSecurityException

Encrypt the given plaintext.

Parameters:

plaintext - Payload to encrypt.

salt - A random 16-byte buffer

privateKey - A private key to encrypt this message with (Web Push: the local private key)

keyid - An identifier for the local key. Only applies to AESGCM. For AES128GCM, the header contains the keyid.

dh - An Elliptic curve Diffie-Hellman public privateKey on the P-256 curve (Web Push: the user's keys.p256dh)

authSecret - An authentication secret (Web Push: the user's keys.auth)

version -

Returns:

Throws:

java.security.GeneralSecurityException

decrypt

public byte[] decrypt(byte[] payload,
                      byte[] salt,
                      byte[] key,
                      java.lang.String keyid,
                      Encoding version)
               throws java.security.InvalidKeyException,
                      java.security.NoSuchAlgorithmException,
                      javax.crypto.IllegalBlockSizeException,
                      java.security.InvalidAlgorithmParameterException,
                      javax.crypto.BadPaddingException,
                      java.security.NoSuchProviderException,
                      javax.crypto.NoSuchPaddingException

Decrypt the payload.

Parameters:

payload - Header and body (ciphertext)

salt - May be null when version is AES128GCM; the salt is extracted from the header.

version - AES128GCM or AESGCM.

Returns:

Throws:

java.security.InvalidKeyException

java.security.NoSuchAlgorithmException

javax.crypto.IllegalBlockSizeException

java.security.InvalidAlgorithmParameterException

javax.crypto.BadPaddingException

java.security.NoSuchProviderException

javax.crypto.NoSuchPaddingException

parseHeader

public byte[][] parseHeader(byte[] payload)

decryptRecord

public byte[] decryptRecord(byte[] ciphertext,
                            byte[] key,
                            byte[] nonce,
                            Encoding version)
                     throws javax.crypto.NoSuchPaddingException,
                            java.security.NoSuchAlgorithmException,
                            java.security.NoSuchProviderException,
                            java.security.InvalidAlgorithmParameterException,
                            java.security.InvalidKeyException,
                            javax.crypto.BadPaddingException,
                            javax.crypto.IllegalBlockSizeException

Throws:

javax.crypto.NoSuchPaddingException

java.security.NoSuchAlgorithmException

java.security.NoSuchProviderException

java.security.InvalidAlgorithmParameterException

java.security.InvalidKeyException

javax.crypto.BadPaddingException

javax.crypto.IllegalBlockSizeException

buildInfo

protected static byte[] buildInfo(java.lang.String type,
                                  byte[] context)

Future versions might require a null-terminated info string?

Parameters:

type -

Returns:

hkdfExpand

protected static byte[] hkdfExpand(byte[] ikm,
                                   byte[] salt,
                                   byte[] info,
                                   int length)

Convenience method for computing the HMAC Key Derivation Function. The real work is offloaded to BouncyCastle.

extractSecretAndContext

public byte[][] extractSecretAndContext(byte[] key,
                                        java.lang.String keyId,
                                        org.bouncycastle.jce.interfaces.ECPublicKey dh,
                                        byte[] authSecret)
                                 throws java.security.InvalidKeyException,
                                        java.security.NoSuchAlgorithmException

Throws:

java.security.InvalidKeyException

java.security.NoSuchAlgorithmException

deriveKeyAndNonce

public byte[][] deriveKeyAndNonce(byte[] salt,
                                  byte[] key,
                                  java.lang.String keyId,
                                  org.bouncycastle.jce.interfaces.ECPublicKey dh,
                                  byte[] authSecret,
                                  Encoding version,
                                  int mode)
                           throws java.security.NoSuchAlgorithmException,
                                  java.security.InvalidKeyException

Throws:

java.security.NoSuchAlgorithmException

java.security.InvalidKeyException

webpushSecret

public byte[] webpushSecret(java.lang.String keyId,
                            org.bouncycastle.jce.interfaces.ECPublicKey dh,
                            byte[] authSecret,
                            int mode)
                     throws java.security.NoSuchAlgorithmException,
                            java.security.InvalidKeyException

Combine Shared and Authentication Secrets See https://tools.ietf.org/html/draft-ietf-webpush-encryption-09#section-3.3.

Parameters:

keyId -

dh -

authSecret -

mode -

Returns:

Throws:

java.security.NoSuchAlgorithmException

java.security.InvalidKeyException