Apparatus and method for protecting message data

Patent metadata

Field	Value
Publication number	US-9729325-B2
Application number	US-201514659082-A
Country	US
Kind code	B2
Filing date	Mar 16, 2015
Priority date	Sep 14, 2012
Publication date	Aug 8, 2017
Grant date	Aug 8, 2017

Abstract

Disclosed is a method for protecting message data. In the method, the message data is padded with padding bits generated based on a deterministic function performed on the message data. The padded message data is compressed to generate compressed data. A length of the compressed data is dependent on the padding bits. The compressed data is encrypted to generate encrypted message data.

First claim

What is claimed is:

1. A method for protecting message data, comprising:
compressing the message data to generate compressed data comprising a first number of data bytes;
padding the compressed data to generate padded compressed data comprising a second number of data bytes, wherein the second number is a variable number and is equal to the first number plus a pad number, and the pad number has a value determined based on a keyed hash of the message data; and
encrypting the padded compressed data to generate encrypted message data.

2. The method of claim 1 , wherein the keyed hash of the message data is performed using a Hashing for Message Authentication (HMAC) cryptographic hash function.

3. The method of claim 1 , wherein the keyed hash uses an obfuscation key derived using a key derivation function.

4. The method of claim 3 , wherein the obfuscation key is generated from an exchanged secret value.

5. The method of claim 3 , wherein the key derivation function uses an encryption key and an authentication key to generate the obfuscation key.

6. The method of claim 5 , wherein the encryption key and the authentication key are generated from an exchanged secret value and from a plurality of non-secret values.

7. The method of claim 1 , wherein the pad number comprises a number from 1 to 32.

8. The method of claim 1 , wherein the message data comprises a Transport Layer Security (TLS) protocol message.

9. The method of claim 1 , wherein the message data comprises a Secure Socket Layer (SSL) protocol message.

10. A remote station, comprising:
means for compressing message data to generate compressed data comprising a first number of data bytes;
means for padding the compressed data to generate padded compressed data comprising a second number of data bytes, wherein the second number is a variable number and is equal to the first number plus a pad number, and the pad number has a value determined based on a keyed hash of the message data; and
means for encrypting the padded compressed data to generate encrypted message data.

11. The remote station of claim 10 , wherein the keyed hash of the message data is performed using a Hashing for Message Authentication (HMAC) cryptographic hash function.

12. The remote station of claim 10 , wherein the keyed hash uses an obfuscation key derived using a key derivation function.

13. The remote station of claim 12 , wherein the obfuscation key is generated from an exchanged secret value.

14. The remote station of claim 12 , wherein the key derivation function uses an encryption key and an authentication key to generate the obfuscation key.

15. The remote station of claim 14 , wherein the encryption key and the authentication key are generated from an exchanged secret value and from a plurality of non-secret values.

16. The remote station of claim 10 , wherein the pad number comprises a number from 1 to 32.

17. The remote station of claim 10 , wherein the message data comprises a Transport Layer Security (TLS) protocol message.

18. The remote station of claim 10 , wherein the message data comprises a Secure Socket Layer (SSL) protocol message.

19. A remote station, comprising:
a processor, implemented as hardware, configured to:
compress message data to generate compressed data comprising a first number of data bytes;
pad the compressed data to generate padded compressed data comprising a second number of data bytes, wherein the second number is a variable number and is equal to the first number plus a pad number, and the pad number has a value determined based on a keyed hash of the message data; and
encrypt the padded compressed data to generate encrypted message data.

20. The remote station of claim 19 , wherein the keyed hash of the message data is performed using a Hashing for Message Authentication (HMAC) cryptographic hash function.

21. The remote station of claim 19 , wherein the keyed hash uses an obfuscation key derived using a key derivation function.

22. The remote station of claim 21 , wherein the obfuscation key is generated from an exchanged secret value.

23. The remote station of claim 21 , wherein the key derivation function uses an encryption key and an authentication key to generate the obfuscation key.

24. The remote station of claim 23 , wherein the encryption key and the authentication key are generated from an exchanged secret value and from a plurality of non-secret values.

25. The remote station of claim 19 , wherein the pad number comprises a number from 1 to 32.

26. The remote station of claim 19 , wherein the message data comprises a Transport Layer Security (TLS) protocol message.

27. The remote station of claim 19 , wherein the message data comprises a Secure Socket Layer (SSL) protocol message.

28. A non-transitory computer-readable medium, comprising:
code for causing a computer to compress message data to generate compressed data comprising a first number of data bytes;
code for causing a computer to pad the compressed data to generate padded compressed data comprising a second number of data bytes, wherein the second number is a variable number and is equal to the first number plus a pad number, and the pad number has a value determined based on a keyed hash of the message data; and
code for causing a computer to encrypt the padded compressed data to generate encrypted message data.

29. The non-transitory computer-readable medium of claim 28 , wherein the keyed hash of the message data is performed using a Hashing for Message Authentication (HMAC) cryptographic hash function.

30. The non-transitory computer-readable medium of claim 28 , wherein the keyed hash uses an obfuscation key derived using a key derivation function.

31. The non-transitory computer-readable medium of claim 30 , wherein the obfuscation key is generated from an exchanged secret value.

32. The non-transitory computer-readable medium of claim 30 , wherein the key derivation function uses an encryption key and an authentication key to generate the obfuscation key.

33. The non-transitory computer-readable medium of claim 32 , wherein the encryption key and the authentication key are generated from an exchanged secret value and from a plurality of non-secret values.

34. The non-transitory computer-readable medium of claim 28 , wherein the pad number comprises a number from 1 to 32.

35. The non-transitory computer-readable medium of claim 28 , wherein the message data comprises a Transport Layer Security (TLS) protocol message.

36. The non-transitory computer-readable medium of claim 28 , wherein the message data comprises a Secure Socket Layer (SSL) protocol message.

Assignees

• Qualcomm Inc

Inventors

• Jacobson David
• Brumley Billy

Classifications

• H04L9/3239

  involving non-keyed hash functions, e.g. modification detection codes [MDCs], MD5, SHA or RIPEMD · CPC title

• H04L2209/24

  Key scheduling, i.e. generating round keys or sub-keys for block encryption · CPC title

• H04L69/04 Primary

  Protocols for data compression, e.g. ROHC · CPC title

• H04L9/3242 Primary

  involving keyed hash functions, e.g. message authentication codes [MACs], CBC-MAC or HMAC · CPC title

• H04L2209/16

  Obfuscation or hiding, e.g. involving white box · CPC title