The Mozilla-JSS JCA Provider
Newsgroup: mozilla.dev.tech.crypto
Overview
This document describes the JCA Provider shipped with JSS. The provider's name is "Mozilla-JSS". It implements cryptographic operations in native code using the NSS libraries.
Contents
- Signed JAR file
- Installing the Provider
- Specifying the CryptoToken
- Supported Classes
- What's Not Supported
Signed JAR file
- JSS 3.2 implements several JCE (Java Cryptography Extension) algorithms. These algorithms have at various times been export-controlled by the US government. Sun therefore requires that JAR files implementing JCE algorithms be digitally signed by an approved organization. Netscape has this approval and signs the official builds of
jss32.jar
. At runtime, the JRE automatically verifies this signature whenever a JSS class is loaded that implements a JCE algorithm. The verification is transparent to the application (unless it fails and throws an exception). If you are curious, you can verify the signature on the JAR file using thejarsigner
tool, which is distributed with the JDK.If you build JSS yourself from source instead of using binaries downloaded from mozilla.org, your JAR file will not have a valid signature. This means you will not be able to use the JSS provider for JCE algorithms. You have two choices.
- Use the binary release of JSS from mozilla.org.
- Apply for your own JCE code-signing certificate following the procedure at How to Implement a Provider for the JavaTM Cryptography Extension. Then you can sign your own JSS JAR file.
- Use the binary release of JSS from mozilla.org.
Installing the Provider
- In order to use any part of JSS, including the JCA provider, you must first call
CryptoManager.initialize()
. By default, the JCA provider will be installed in the list of providers maintained by thejava.security.Security
class. If you do not wish the provider to be installed, create aCryptoManager.InitializationValues
object, set itsinstallJSSProvider
field tofalse
, and pass theInitializationValues
object toCryptoManager.initialize()
.
Specifying the CryptoToken
- All cryptographic operations in JSS and NSS occur on a particular PKCS #11 token, implemented in software or hardware. There is no clean way to specify this token through the JCA API. By default, the JSS provider carries out all operations except MessageDigest on the Internal Key Storage Token, a software token included in JSS/NSS. MessageDigest operations take place by default on the Internal Crypto Token, another internal software token in JSS/NSS. There is no good design reason for this difference, but it is necessitated by a quirk in the NSS implementation.
In order to use a different token, use
CryptoManager.setThreadToken()
. This sets the token to be used by the JSS JCA provider in the current thread. When you callgetInstance()
on a JCA class, the JSS provider checks the current per-thread default token (by callingCryptoManager.getThreadToken()
) and instructs the new object to use that token for cryptographic operations. The per-thread default token setting is only consulted insidegetInstance()
. Once a JCA object has been created it will continue to use the same token, even if the application later changes the per-thread default token.Whenever a new thread is created, its token is initialized to the default, the Internal Key Storage Token. Thus, the thread token is not inherited from the parent thread.
The following example shows how you can specify which token is used for various JCA operations:
// Lookup PKCS #11 tokens CryptoManager manager = CryptoManager.getInstance(); CryptoToken tokenA = manager.getTokenByName("TokenA"); CryptoToken tokenB = manager.getTokenByName("TokenB"); // Create an RSA KeyPairGenerator using TokenA manager.setThreadToken(tokenA); KeyPairGenerator rsaKpg = KeyPairGenerator.getInstance("RSA", "Mozilla-JSS"); // Create a DSA KeyPairGenerator using TokenB manager.setThreadToken(tokenB); KeyPairGenerator dsaKpg = KeyPairGenerator.getInstance("DSA", "Mozilla-JSS"); // Generate an RSA KeyPair. This will happen on TokenA because TokenA // was the per-thread default token when rsaKpg was created. rsaKpg.initialize(1024); KeyPair rsaPair = rsaKpg.generateKeyPair(); // Generate a DSA KeyPair. This will happen on TokenB because TokenB // was the per-thread default token when dsaKpg was created. dsaKpg.initialize(1024); KeyPair dsaPair = dsaKpg.generateKeyPair();
Supported Classes
- Cipher
- DSAPrivateKey
- DSAPublicKey
- KeyFactory
- KeyGenerator
- KeyPairGenerator
- Mac
- MessageDigest
- RSAPrivateKey
- RSAPublicKey
- SecretKeyFactory
- SecretKey
- SecureRandom
- Signature
What's Not Supported
- The following classes don't work very well:
- KeyStore: There are many serious problems mapping the JCA keystore interface onto NSS's model of PKCS #11 modules. The current implementation is almost useless. Since these problems lie deep in the NSS design and implementation, there is no clear timeframe for fixing them. Meanwhile, the
org.mozilla.jss.crypto.CryptoStore
class can be used for some of this functionality.
- KeyStore: There are many serious problems mapping the JCA keystore interface onto NSS's model of PKCS #11 modules. The current implementation is almost useless. Since these problems lie deep in the NSS design and implementation, there is no clear timeframe for fixing them. Meanwhile, the
Cipher
Supported Algorithms
Notes
-
- AES
- DES
- DESede (DES3 )
- RC2
- RC4
- RSA
- The following modes and padding schemes are supported:
Algorithm Mode Padding DES ECB NoPadding CBC NoPadding PKCS5 Padding DESede
DES3ECB NoPadding CBC NoPadding PKCS5 Padding AES ECB NoPadding CBC NoPadding PKCS5 Padding RC4 None None RC2 CBC NoPadding PKCS5Padding - The SecureRandom argument passed to
initSign()
andinitVerify()
is ignored, because NSS does not support specifying an external source of randomness.
DSAPrivateKey
getX()
is not supported because NSS does not support extracting data from private keys.
KeyFactory
Supported Algorithms
Notes
-
- DSA
- RSA
- The following transformations are supported for
generatePublic()
andgeneratePrivate()
:From To RSAPublicKeySpec
RSAPublicKey
DSAPublicKeySpec
DSAPublicKey
X509EncodedKeySpec
RSAPublicKey
DSAPublicKey
RSAPrivateCrtKeySpec
RSAPrivateKey
DSAPrivateKeySpec
DSAPrivateKey
PKCS8EncodedKeySpec
RSAPrivateKey
DSAPrivateKey
getKeySpec()
is not supported. This method exports key material in plaintext and is therefore insecure. Note that a public key's data can be accessed directly from the key.translateKey()
simply gets the encoded form of the given key and then tries to import it by callinggeneratePublic()
orgeneratePrivate()
. OnlyX509EncodedKeySpec
is supported for public keys, and onlyPKCS8EncodedKeySpec
is supported for private keys.
KeyGenerator
Supported Algorithms
Notes
-
- AES
- DES
- DESede (DES3 )
- RC4
- The SecureRandom argument passed to
init()
is ignored, because NSS does not support specifying an external source of randomness. - None of the key generation algorithms accepts an
AlgorithmParameterSpec
.
KeyPairGenerator
Supported Algorithms
Notes
-
- DSA
- RSA
- The SecureRandom argument passed to initialize() is ignored, because NSS does not support specifying an external source of randomness.
Mac
Supported Algorithms
Notes
-
- HmacSHA1 (Hmac-SHA1 )
- Any secret key type (AES, DES, etc.) can be used as the MAC key, but it must be a JSS key. That is, it must be an
instanceof org.mozilla.jss.crypto.SecretKeyFacade
. - The params passed to
init()
are ignored.
MessageDigest
Supported Algorithms
-
- MD5
- MD2
- SHA-1 (SHA1, SHA )
RSAPrivateKey
Notes
-
getModulus()
is not supported because NSS does not support extracting data from private keys.getPrivateExponent()
is not supported because NSS does not support extracting data from private keys.
SecretKeyFactory
Supported Algorithms
Notes
-
- AES
- DES
- DESede (DES3 )
- PBAHmacSHA1
- PBEWithMD5AndDES
- PBEWithSHA1AndDES
- PBEWithSHA1AndDESede (PBEWithSHA1AndDES3 )
- PBEWithSHA1And128RC4
- RC4
generateSecret
supports the following transformations:KeySpec Class Key Algorithm PBEKeySpec
org.mozilla.jss.crypto.PBEKeyGenParamsUsing the appropriate PBE algorithm:
DES
DESede
RC4DESedeKeySpec DESede DESKeySpec DES SecretKeySpec AES
DES
DESede
RC4getKeySpec
supports the following transformations:Key Algorithm KeySpec Class DESede DESedeKeySpec DES DESKeySpec DESede
DES
AES
RC4SecretKeySpec - For increased security, some SecretKeys may not be extractable from their PKCS #11 token. In this case, the key should be wrapped (encrypted with another key), and then the encrypted key might be extractable from the token. This policy varies across PKCS #11 tokens.
translateKey
tries two approaches to copying keys. First, it tries to copy the key material directly using NSS calls to PKCS #11. If that fails, it callsgetEncoded()
on the source key, and then tries to create a new key on the target token from the encoded bits. Both of these operations will fail if the source key is not extractable.- The class
java.security.spec.PBEKeySpec
in JDK versions earlier than 1.4 does not contain the salt and iteration fields, which are necessary for PBE key generation. These fields were added in JDK 1.4. If you are using a JDK (or JRE) version earlier than 1.4, you cannot use classjava.security.spec.PBEKeySpec
. Instead, you can useorg.mozilla.jss.crypto.PBEKeyGenParams
. If you are using JDK (or JRE) 1.4 or later, you can usejava.security.spec.PBEKeySpec
ororg.mozilla.jss.crypto.PBEKeyGenParams
.
SecretKey
Supported Algorithms
Notes
-
- AES
- DES
- DESede (DES3 )
- HmacSHA1
- RC2
- RC4
SecretKey
is implemented by the classorg.mozilla.jss.crypto.SecretKeyFacade
, which acts as a wrapper around the JSS classSymmetricKey
. AnySecretKeys
handled by JSS will actually beSecretKeyFacades
. This should usually be transparent.
SecureRandom
Supported Algorithms
Notes
-
- pkcs11prng
- This invokes the NSS internal pseudorandom number generator.
Signature
Supported Algorithms
Notes
-
- SHA1withDSA (DSA, DSS, SHA/DSA, SHA-1/DSA, SHA1/DSA, DSAWithSHA1, SHAwithDSA )
- SHA-1/RSA (SHA1/RSA, SHA1withRSA )
- MD5/RSA (MD5withRSA )
- MD2/RSA
- The
SecureRandom
argument passed toinitSign()
andinitVerify()
is ignored, because NSS does not support specifying an external source of randomness.
- The following classes don't work very well: