A User Centric Security Model for Tamper-Resistant Devices

C.11 Implementation Helper Classes
102 private byte [ ] DHContribution = new byte [ 5 1 2 ] ;
103 void p r o t o c o l I n i t i a l i s e ( ) {
104 try {
105 KeyPairGenerator myKeyGenerator = KeyPairGenerator . g e t I n s t a n c e (
106 "RSA" ) ;
107 myKeyGenerator . i n i t i a l i z e (512) ;
108 KeyPair myKeyPair = myKeyGenerator . genKeyPair ( ) ;
109 mySignatureGenerationKey = myKeyPair . g e t P r i v a t e ( ) ;
110 mySignatureVerificationKey = myKeyPair . g e t P u b l i c ( ) ;
111 mySignature = S i g n a t u r e . g e t I n s t a n c e ( "SHA1withRSA" ) ;
112 } catch ( Exception cE ) {
113 System . out . p r i n t l n (
114 " P r o t o c o l Helper Class I n i t i a l i s a t i o n F a i l e d : "
+ cE . getMessage ( ) ) ;
115 }
116 }
117 byte [ ] GenerateDHPublicValue ( ) throws NoSuchAlgorithmException ,
118 InvalidKeyException ,
119 I l l e g a l B l o c k S i z e E x c e p t i o n ,
120 NoSuchProviderException ,
121 BadPaddingException ,
122 NoSuchPaddingException ,
123 InvalidKeySpecException {
124 rsaCipher = Cipher . g e t I n s t a n c e ( "RSA/None/NoPadding" , "BC" ) ;
125 KeyFactory myKeyFactory = KeyFactory . g e t I n s t a n c e ( "RSA" , "BC" ) ;
126 myRNG = SecureRandom . g e t I n s t a n c e ( "SHA1PRNG" ) ;
127 myRNG. nextBytes ( randomExponent ) ;
128 RSAPublicKeySpec myPublicKeySpec = new RSAPublicKeySpec (new
129 B i g I n t e g e r ( dhModulus , 16) , new B i g I n t e g e r ( byteToString
130 ( randomExponent ) , 16) ) ;
131 myRSAPublicKey = ( RSAPublicKey ) myKeyFactory . g e n e r a t e P u b l i c
132 ( myPublicKeySpec ) ;
133 rsaCipher . i n i t ( Cipher .ENCRYPT_MODE, myRSAPublicKey ) ;
134 DHContribution = rsaCipher . doFinal ( dhBase ) ;
135 return DHContribution ;
136 }
137 byte [ ] GenerateDHSessionKeyMaterial (byte [ ] i n b u f f , int o f f s e t , int
138 l e n g t h ) throws NoSuchAlgorithmException , InvalidKeyException ,
139 I l l e g a l B l o c k S i z e E x c e p t i o n , NoSuchProviderException ,
140 BadPaddingException , NoSuchPaddingException ,
141 InvalidKeySpecException {
142 rsaCipher . i n i t ( Cipher .ENCRYPT_MODE, myRSAPublicKey ) ;
143 return rsaCipher . doFinal ( i n b u f f , o f f s e t , l e n g t h ) ;
144 }
145 void GenerateMac ( byte [ ] i n b u f f , int i n b u f f O f f s e t , int inbuffLength ,
146 byte [ ] outbuff , int o u t b u f f O f f s e t , byte [ ] MacKey)
147 throws NoSuchAlgorithmException ,
148 InvalidKeyException , I l l e g a l B l o c k S i z e E x c e p t i o n ,
149 NoSuchProviderException , BadPaddingException ,
150 NoSuchPaddingException , InvalidKeySpecException {
151 AESEngine AESMacEngine = new AESEngine ( ) ;
436