Package de.svenkubiak.webpush4j

Class HttpEce

java.lang.Object

de.svenkubiak.webpush4j.HttpEce

public class HttpEce
extends 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	Description
static final int	KEY_LENGTH
static final int	SHA_256_LENGTH
static final int	TAG_SIZE
static final int	TWO_BYTE_MAX
static final String	WEB_PUSH_INFO

Constructor Summary

Constructors

Constructor	Description
HttpEce()
HttpEce(Map<String,KeyPair> keys, Map<String,String> labels)

Method Summary

Modifier and Type	Method	Description
protected static byte[]	buildInfo(String type, byte[] context)	Future versions might require a null-terminated info string?
byte[]	decrypt(byte[] payload, byte[] salt, byte[] key, String keyid, Encoding version)	Decrypt the payload.
byte[]	decryptRecord(byte[] ciphertext, byte[] key, byte[] nonce, Encoding version)
byte[][]	deriveKeyAndNonce(byte[] salt, byte[] key, String keyId, org.bouncycastle.jce.interfaces.ECPublicKey dh, byte[] authSecret, Encoding version, int mode)
byte[]	encrypt(byte[] plaintext, byte[] salt, byte[] privateKey, String keyid, org.bouncycastle.jce.interfaces.ECPublicKey dh, byte[] authSecret, Encoding version)	Encrypt the given plaintext.
byte[][]	extractSecretAndContext(byte[] key, 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(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 Details

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 String WEB_PUSH_INFO

See Also:

• Constant Field Values

Constructor Details

HttpEce

public HttpEce()

HttpEce

public HttpEce(Map<String,KeyPair> keys,
 Map<String,String> labels)

Method Details

encrypt

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

GeneralSecurityException

decrypt

public byte[] decrypt(byte[] payload,
 byte[] salt,
 byte[] key,
 String keyid,
 Encoding version)
               throws InvalidKeyException,
NoSuchAlgorithmException,
IllegalBlockSizeException,
InvalidAlgorithmParameterException,
BadPaddingException,
NoSuchProviderException,
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:

InvalidKeyException

NoSuchAlgorithmException

IllegalBlockSizeException

InvalidAlgorithmParameterException

BadPaddingException

NoSuchProviderException

NoSuchPaddingException

parseHeader

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

decryptRecord

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

Throws:

NoSuchPaddingException

NoSuchAlgorithmException

NoSuchProviderException

InvalidAlgorithmParameterException

InvalidKeyException

BadPaddingException

IllegalBlockSizeException

buildInfo

protected static byte[] buildInfo(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,
 String keyId,
 org.bouncycastle.jce.interfaces.ECPublicKey dh,
 byte[] authSecret)
                                 throws InvalidKeyException,
NoSuchAlgorithmException

Throws:

InvalidKeyException

NoSuchAlgorithmException

deriveKeyAndNonce

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

Throws:

NoSuchAlgorithmException

InvalidKeyException

webpushSecret

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

NoSuchAlgorithmException

InvalidKeyException