The Integration of the Bundle Security Protocol Features

into DTN2

Walter J. Scheirer and Prof. Mooi Choo Chuah

Department of Computer Science and Engineering

Lehigh University

References:

Bundle Security Protocol Specification draft-irtf-dtnrg-bundle-security-00, June 8, 2005

Bundle Protocol Specification draft-irtf-dtnrg-bundle-spec-03.txt, July 2005 * draft-irtf-dtnrg-bundle-spec-02.txt, Sept. 2004

DTN2 Sept. 6, 2005 CVS revision Current

Major Features

Bundle Authentication Header (BAH)Payload Security Header (PSH)Confidentiality Header (CH)Bundle Fragmentation/Reassembly

Summary of Technical Approach

Bundle Authentication Header (BAH) The BAH is used to assure the authenticity of the bundle

along a single hop from sender to recipient Payload Security Header (PSH)

The PSH is used to assure the authenticity of the bundle from the PSH security source, which creates the PSH, to the PSH security destination, which verifies the PSH authenticator

Confidentiality Header (CH) The CH is used to indicate that the bundle payload has

been encrypted while en route between the CH source and the CH security destination

Summary of Technical Approach

Each node will turn on the optional security-related delivery option parameters if it desires certain security features - if it desires confidentiality, then a CH header

must be applied to the bundle if it desires authentication, a PSH and/or a BAH

must be applied and the relevant parts of the bundle digitally signed or MACed appropriately

Bundle with security headers

BAH(w/ signedHash value

All other Headers

PrimaryBundleHeader

PayloadClass

Len.Payload

AE78F98D567BB32CAD5F4D

PSH(w/ signed

Hash value)

Confid.Header

567BB32 CAD5F4DAll other Headers

PrimaryBundleHeader

Len.PayloadSegment

Size

PayloadHashSize

Toilet PaperCiphersuite

ID

Formatflag

Key ID(optional)

Len. 0

BAH

All other Headers

PrimaryBundleHeader

PayloadClass

Len.Payload

AE78F98D

PayloadSegment

Size

PayloadHashSize

Toilet PaperCiphersuite

ID

Formatflag

NextHdr

Key ID(optional)

Len. 0PSH

(w/ signedHash value)

BAH

FragmentHeader

(offset=9)

NextHdr

PSH, confidentiality header and payload class field deleted from successive fragments

Authent. ofHdr & payload

segment

Authent. ofHdr & payload

segment

FragmentHeader

(offset=0)

Authent. ofHdr & payload

segment

Confid.Header

Challenges faced in fragmentation scenario:

Implementation Details

Ciphersuites Have been implemented using the OpenSSL (v.

0.9.7a, Fedora Core 2) library Significant code addition to

servlib/bundling/BundleProtocol.cc

BAH EntireBundleHMAC, HeadofBundleHMAC,

HeadOfBundleSig, EntireBundleSig, EntireBundleMAC

Implementation Details

PSH EntireBundleHMAC

CH Payload Encryption - Blowfish

Support different combinations of Headers BAH, PSH, CH; BAH and PSH; BAH and CH

Implementation Details

Security Headers

populate header fields

apply ciphersuite

append to bundle

Sending

parse header fields

apply ciphersuite

verify integrity

Receiving

Implementation Details

Protocol Stack

Bundle Transmitted

BundleProtocol.cc /

format_headers()

build CH

build PSH

build BAH

TCP Convergence Layer Bundle Received

BundleProtocol.cc /

parse_headers()

check CH

check PSH

check BAH

TCP Convergence Layer

Questions?