org.mobicents.media.server.impl.rtp.crypto

Class SRTPCipherCTR

java.lang.Object

org.mobicents.media.server.impl.rtp.crypto.SRTPCipherCTR

public class SRTPCipherCTR
extends Object

SRTPCipherCTR implements SRTP Counter Mode AES Encryption (AES-CM). Counter Mode AES Encryption algorithm is defined in RFC3711, section 4.1.1. Other than Null Cipher, RFC3711 defined two two encryption algorithms: Counter Mode AES Encryption and F8 Mode AES encryption. Both encryption algorithms are capable to encrypt / decrypt arbitrary length data, and the size of packet data is not required to be a multiple of the AES block size (128bit). So, no padding is needed. Please note: these two encryption algorithms are specially defined by SRTP. They are not common AES encryption modes, so you will not be able to find a replacement implementation in common cryptographic libraries. As defined by RFC3711: Counter Mode Encryption is mandatory.. mandatory to impl optional default ------------------------------------------------------------------------- encryption AES-CM, NULL AES-f8 AES-CM message integrity HMAC-SHA1 - HMAC-SHA1 key derivation (PRF) AES-CM - AES-CM We use AESCipher to handle basic AES encryption / decryption.

Author:

Werner Dittmann ([email protected]), Bing SU ([email protected])

Constructor Summary

Constructors

Constructor and Description
SRTPCipherCTR()

Method Summary

Methods

Modifier and Type	Method and Description
void	getCipherStream(org.bouncycastle.crypto.BlockCipher aesCipher, byte[] out, int length, byte[] iv) Computes the cipher stream for AES CM mode.
void	process(org.bouncycastle.crypto.BlockCipher cipher, ByteBuffer data, int off, int len, byte[] iv)

Methods inherited from class java.lang.Object

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

Constructor Detail

SRTPCipherCTR

public SRTPCipherCTR()

Method Detail

process

public void process(org.bouncycastle.crypto.BlockCipher cipher,
           ByteBuffer data,
           int off,
           int len,
           byte[] iv)

getCipherStream

public void getCipherStream(org.bouncycastle.crypto.BlockCipher aesCipher,
                   byte[] out,
                   int length,
                   byte[] iv)

Computes the cipher stream for AES CM mode. See section 4.1.1 in RFC3711 for detailed description.

Parameters:

out - byte array holding the output cipher stream

length - length of the cipher stream to produce, in bytes

iv - initialization vector used to generate this cipher stream