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Auditing Cryptographic Key
Management
Andrew Moore BSc ACA CISA CISSP
IT Audit Manager Barclays Bank PLC
19 October 2005
Auditing Cryptographic Key Management
Session Overview
• Basic cryptographic mechanisms
• Importance of cryptographic controls
• Control objectives for cryptographic keys & Large-
scale Key Management in Financial Services
• Audit approach
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
International Standards
Organisation Example standard
IETF RFC 1321 MD5 Hash Algorithm
RFC 2459 X.509 digital certificates
ISO ISO 14888-3 Digital Signature Algorithm
NIST FIPS 140-2 Security requirements for
cryptographic modules
ANSI ANSI X 9.24 – Financial Services Key Management
using the DEA
RSA Labs PKCS 1 to 13. Public Key Cryptography Standards
IEEE P1363 standards on Public Key cryptography
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Basic Cryptographic Mechanisms
• General principles
• Symmetric cryptography (e.g. DES)
• Asymmetric cryptography (e.g. RSA)
• Hash functions (e.g. SHA-1)
• Message authentication codes (e.g. HMAC)
• Digital signatures (e.g. DSA)
• Digital Certificates (e.g. X.509)
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
General principles
• Kerckhoff‟s Principle. Only the key should be
secret. Cryptographic mechanisms depend on the
confidentiality of keys. Algorithms are in the
public domain.
• Over time algorithms become „less secure‟ as
research and technology progresses
• To engage in secure communications there is a
need to securely distribute a secret key or public
key.
• Keys should be changed on a regular basis.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Symmetric Cryptography
Encryption C=Ek(P)
Plaintext Encryption Ciphertext
Algorithm
Key
Decryption P= Dk(C)
Ciphertext Decryption Plaintext
Algorithm
Key
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Symmetric Cryptography (continued)
Example algorithms
Algorithm Key Length Block Standards
Size
DES, 56 112/168 64 FIPS 46 / ANSI X3.92
Triple-DES
AES 128 128 FIPS 197
KASUMI 128 64 #1
IDEA 128 64 #2
#1 – likely to be included in ISO 18033 #1, #2 included in ISO 9979
Other algorithms: Lucifer, Madryga, NewDES, FEAL, REDOC, LOKI, Khufu, Khafre, RC2,
MMB, CA-1.1, Skipjack, GOST, CAST, Blowfish, SAFER, 3-Way, Crab, MBAL, RC5, Crypto-
Meccano, McEliece, Rao-Nam, Li-Wang, CALC, TEA, Vino, MacGuffin, BaseKing.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Asymmetric Cryptography
Key Generation: Private Key Public Key
Encryption C=Ek1(P)
Plaintext Encryption Ciphertext
Algorithm
Public Key
Decryption P=Dk2(C)
Ciphertext Decryption
Plaintext
Algorithm
Private Key
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Asymmetric Cryptography (continued)
Example algorithms
Algorith Key length Based on Standard
m
RSA 512/1024/2048/4096 Factoring large primes RSA PKCS #1
ElGamal 512/1024/2048/4096 Discrete logarithms -
ECC 130 - 200
Other standards: IEEE 1363, ISO 18033-2 Elliptic Curves RSA PKCS #13
Other algorithms: Knapsack, Pohlig-Hellman, Rabin, Williams, McEliece, LUC, FAPKC.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Hash Function
Generate Hash Code
Input Hash Fixed
(any size) Function length Hash
Code
Requirements of a Hash Function:
• One way
• Collision resistance
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Hash Function (continued)
Example algorithms
Function Hash size Standards
(bits)
SHA-1 160 IETF RFC 3174 / NIST FIPS 180 / ISO
10118-3
RIPEMD- 128 ISO 10118-3
Other examples include: SHA-224, SHA-256, SHA-384, SHA-512, RIPEMD-160,
128
WHIRLPOOL, MD2, MD4, MD5
MD5 128 IETF RFC 1321
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Message Authentication Codes
MAC generation
Plaintext MAC Fixed length
Algorithm MAC
Key
Requirements of a MAC Algorithm:
•Usability – Computing a MAC from a message and a
key must be straight-forward
•Infeasible to find a MAC for a given message without
the secret key
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Message Authentication Codes (continued)
Example algorithms
Algorithm Type Standard
SMAC, EMAC, ARMAC, Block cipher ISO 9797-1
MacDES CBC
HMAC Hash function ISO 9797-2, IETF RFC
2104
MAA Dedicated ISO 8731-2
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Digital Signatures
Key Generation: Private Key Public Key
Signing
Plaintext Signed
Hash Asymmetric
Encryption message
Private Key Algorithm
Verification
Signed
message Verification “Valid”or
Algorithm ”invalid”
Public key
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Digital Signatures (continued)
Example Algorithms:
Algorith Standards
m
DSA NIST FIPS 186, ANSI X9.30 & x9.62, IEEE 1363, ISO
14888-3
Other algorithms: GOST, ElGamal, Ong-Schnorr-Shamir, ESIGN, Cellular Automata,
RSA ANSI
Matsumoto-Imai, Cade, Yagisawax9.31, ISO 9796-2 & 14888-3
based
Note:
Digital signatures do not provide confidentiality – just message
integrity, confirmation of source and possibly non-repudiation (if
ownership and confidentiality of the private key is provable).
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Digital Certificates
Include:
•Distinguished Name
•Public Key
•Key usage
•Signed by a trusted third party (digital signature)
IETF RFC 2459 defines the X.509 v3 certificate
format
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Basic Cryptographic Mechanisms
• General principles
• Symmetric cryptography (e.g. DES)
• Asymmetric cryptography (e.g. RSA)
• Hash functions (e.g. SHA-1)
• Message authentication codes (e.g. HMAC)
• Digital signatures (e.g. DSA)
• Digital Certificates (e.g. X.509)
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Auditing Cryptographic Key Management
• Basic cryptographic mechanisms
• Importance of cryptographic controls
• Control objectives for cryptographic keys & Large-
scale Key Management in Financial Services
• Audit approach
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Importance of cryptographic controls
ISO 7498-2 (OSI Security Architecture) defines thirteen
Security Mechanisms that deliver five Security
Services:
1. Authentication
2. Access Control
3. Data Confidentiality
4. Data Integrity
5. Non-repudiation
In addition to the security services defined above there are also
privacy and availability security requirements.
Note: Definitions of the above can be found in IETF RFC 2828
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Security Services and Mechanisms
Per ISO 7498 -2
Security Service Security Mechanisms
Authentication Encipherment, digital signature, authentication
protocols
Access Control Access control mechanisms (e.g RACF). Privileged
Management Infrastructure (PMI).
Data Confidentiality Encipherment
Data Integrity Encipherment, digital signature, MAC
Non-repudiation Digital signature, data integrity, notarisation (e.g.
Kerberos, PKI).
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
War Stories –Cryptographic controls
• Sumitomo Mitsui – Police foil £220m bank theft
• Cardsystems Solutions inc – 40million credit card numbers
stolen
• Natwest shut off features to its million-plus online banking
customers in response to phishing attacks (BBC News 2004)
Positives:
• “Chip & PIN cutting card fraud” – Fraud involving the
stealing and counterfeiting of debit & credit cards has fallen
29% year-on-year. BBC News Online 9 October 05.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Example 1: Online Banking
• SSL for authentication of the website. Password or token for
authentication of client.
• Authentication for each component of the infrastructure.
Kerberos, PKI.
• Encryption of data transmitted across each component of the
infrastructure to ensure data confidentiality.
• Data integrity. MAC, Hash.
• Non-repudiation – Provably secure authentication and
processing.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Example 1: Online Banking
Customer SSL session Webserver HSM
browser
A, E, I
HSM Content TTP HSM
delivery
server PKI, Kerberos
or other
A, E, I
HSM Internet
Application
HSM Server
Key
A, E, I
A, E, I A: Authentication
Legacy System Transaction
Customer handler E: Encryption
account HSM I: Integrity
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Example 2: Credit card processing
Credit card processing requires multiple parties:
• Scheme (VISA, Mastercard, etc)
• Issuer Bank
• Acquirer Bank
• Merchant / ATM
• Card Bureau
• Card Supplier
• PIN Mailer
Requires: Authentication, confidentiality, integrity, non-
repudiation.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Example 2: Credit card processing
Chip & PIN. Validation of the PIN input in an „online‟
transaction at a merchant or ATM.
Card POS device Eawk(PIN) Acquirer Bank
or ATM
PIN
1. Encrypt PIN Eawk(PIN)
Eawk(PIN)
Card Scheme 2. Decrypt Eawk(PIN)
(e.g. VISA) and re-encrypt
Eiwk(PIN)
Eiwk(PIN)
3. Decrypt Eiwk(PIN) Issuer Bank
and re-encrypt
Eihwk(PIN)
4. Compare Eihwk(PIN)
to stored Eihwk(PIN)
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Example 3: Public Key Infrastructure (PKI)
FO1 Smartcard
Registration fulfilment
FO2 Authority
(RA)
FO3
End-Users
Certification
Authority
App1 OCSP (CA)
App2
LDAP
App3 Root
Sub-CA Sub-CA Sub-CA
Use Use Use Use Use
r r r r r
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Auditing Cryptographic Key Management
• Basic cryptographic mechanisms
• Importance of cryptographic controls
• Control objectives for cryptographic keys & Large-
scale Key Management in Financial Services
• Audit approach
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Control Objectives for Cryptographic Keys
Cryptographic controls are only effective if the
following are assured:
• Integrity of public and private keys
• Authenticity of public and private keys
• Availability of public and private keys
• Confidentiality of private keys
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
War Stories – key management
weaknesses
• Ex Microsoft employees obtained Verisign certificates
• DVD encryption broken because one licensee omitted to
encrypt the decryption key.
• Cambridge researchers publish cryptographic attack to
obtain PIN codes.
• Hackers encrypt business critical data and extort money
from the owner for disclosure of the cryptographic key.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
The Challenge:
Characteristics of cryptographic keys
Characteristic Examples
Symmetric / Single secret key or public / private key pairs
Asymmetric
Variable lifetime Single use to 20 years+
Variable key length 56/112/168 bit DES 512/1024/2048/4096 bit RSA
Different functionality Key Encryption Key, Session key
Control requirements Archive, export
Physical location Generated and stored in same device generated,
stored, used in multiple devices in multiple third parties.
Storage In hardware security modules, encrypted under a KEK in
software, in multiple key parts on paper.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Key Management standards
Standard Description
ISO 11770 Three part general purpose standard on key
management
ANSI X9.17 Key management issues between banking
establishments. Based on Single DES. Now
withdrawn.
ISO 8732 Based on X9.17
ANSI X9.24 Key management between retail banking devices.
ISO 11568 Based on X9.24
NIST 800-57 Recommendation for Key Management
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Key lifecycle (per ISO 11770)
Generation
Activation
Deactivation
Reactivation
Destruction
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Key lifecycle (per ISO 11770)
Generation Generate Key Mandatory
Register Key Optional
Create key Optional
Activation certificate
Optional
Distribute key
Optional
Deactivation Store key
Reactivation
Destruction
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Key lifecycle (per ISO 11770)
Generation Install key Mandatory
Create key Optional
certificate
Optional
Activation Derive key
Optional
Distribute key
Optional
Register key
Deactivation Optional
Store key
Reactivation
Destruction
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Key lifecycle (per ISO 11770)
Generation
Activation
Archive key Optional
Deactivation Revoke key Optional
Store key Optional
Reactivation
Destruction
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Key lifecycle (per ISO 11770)
Generation
Activation
Deactivation
Install key Mandatory
Create key Optional
certificate
Reactivation Optional
Derive key
Optional
Distribute key
Optional
Destruction Store key
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Key lifecycle (per ISO 11770)
Generation
Activation
Deactivation
Reactivation Destroy key Mandatory
Deregister key Mandatory
Archive key Optional
Destruction
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
ISO 11568 “Principles of key management”
1. Keys shall only exist in those forms permitted by ISO 11568
2. No one person shall have the capability to access or ascertain any
plaintext secret key.
3. Systems shall prevent the disclosure of any secret key that has
been or will be used to protect any data.
4. Secret keys shall be generated using a process such that it is not
possible to predict any resultant value or to determine that certain
values are more probable than others from the total set of all the
possible values.
5. Systems should detect the attempted disclosure of any secret key
and the attempted use of a secret key for other than its intended
purpose.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
ISO 11568 “Principles of key management”
(continued)
6. Systems shall prevent or detect the use of a secret key, or portion
of that key, for other than its intended purpose, and the accidental
or unauthorised modification, use, substitution, deletion or
insertion of any key.
7. A key shall be replaced with a new key within the time deemed
feasible to determine the old key.
8. A key shall be replaced with a new key within the time deemed
feasible to perform a successful dictionary attack on the data
enciphered under the old key.
9. A key shall cease to be used when its compromise is known or
suspected.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
ISO 11568 “Principles of key management”
(continued)
10. The compromise of a key shared among one group of parties shall
not compromise keys shared among any other group of parties.
11. A compromised key shall not provide any information to enable the
determination of its replacement.
12. A key shall only be loaded into a device when it may be reasonably
assured that the device is secure and has not been subjected to
unauthorised modification or substitution.
_____________________________________________
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
ISO 11568 Principle 1
1. Keys shall only exist in those forms permitted by ISO 11568
– Within a secure cryptographic device
– In an enciphered form using a Key Encryption Key (KEK) which
either exists in a cryptographic device or is encrypted under a higher
level KEK
– In the form of at least two separate key components protected by
split knowledge and dual control
Note: If a compromise would affect only one party, plaintext secret keys
may also exist in a physically secure environment operated by, or on
behalf of, that party.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Hardware Security Modules
HSM devices store keys and
perform cryptographic
functions in a secure, tamper
evident environment.
NIST FIPS 140-2 defines the
security requirements for
hardware security modules.
Levels 1 to 4.
IBM 4758 cryptographic co- What makes a device NIST
processor first to be certified FIPS 140-2 L4 complaint?
as level 4 compliant.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Key Hierarchy
Recovery Key
Offline
HSM in clear & Master Key Master Key
Database Erk(MK)
Key Encryption Key Encryption Key Encryption
Database Emk(kek) Key (KEK) Key (KEK) Key (KEK)
Database Ekek(DK) and/or Data / Session Data / Session Data / Session
Key Key Key
Application in HSM in clear
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Storage of key components using split
knowledge
Key split into 3 components Key component
Logging and checks Tamper evident
bags
Contents and access logging Lockable safe
drawer
Separate key holder. Regular Safe
audit
Dual access control Biometrics Secure room
Logging
Restricted access Restricted area
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
ISO 11568 Principles 2 and 3
“No one person shall have the capability to access or
ascertain any plaintext secret key.”
“Systems shall prevent the disclosure of any secret key
that has been or will be used to protect any data”
• Segregation of duties controls
• Logical access controls
• Physical security controls
• Control Vectors
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Issues to look for – Dr Strangelove
Beware a “Plan R”
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Segregation of duties controls
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Logical Access Controls
HSM TKE
WS
1 2 3
DKMS
Application ICSF DKMS WS
CKDS
Key
storage
4 5
Mainframe
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Physical Security Controls
Video Surveillance
TKE DKMS PIN
WS Mailer
Dual control
Safe Other Access logging,
monitoring and alarm
Faraday Cage
“level 1” Biometric access
“Level 2” restricted access
“Level 3” employee access
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Control Vectors
What is to stop the application making the following call…
Decrypt (EKEK(Data Key), KEK name)
…and getting the data key out in clear?
Answer: Control Vectors
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Control Vectors (continued)
When a key is Imported into the HSM for use, the key is
encrypted with the master key exclusive OR’ed with a
Control Vector (CV). The CV used depends on the type
of key.
E MKCV(Data Key)
When the key is used, cryptographic functions in the
HSM re-apply the CV depending on the function being
used. If the function is different to that which the CV
allows, then the result is nonsense – as the wrong CV is
used.
This is used to protect Key Encryption Keys being used
to decrypt data keys.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
ISO 11568 Principle 4
“Secret keys shall be generated using a process such
that it is not possible to predict any resultant value or to
determine that certain values are more probable than
others from the total set of all the possible values.”
Key Generation:
• Must be „random‟ or non-deterministic (NIST FIPS
140-2)
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Importance of randomness
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
ISO 11568 Principle 5
“Systems should detect the attempted disclosure of any
secret key and the attempted use of a secret key for
other than its intended purpose.”
• Tamper evident bags
• Control Vectors
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
ISO 11568 Principle 6
“Systems shall prevent or detect the use of a secret key,
or portion of that key, for other than its intended purpose,
and the accidental or unauthorised modification, use,
substitution, deletion or insertion of any key.”
• Tamper evident bags
• Control Vectors
• Monitoring of use of „sensitive‟ cryptographic functions
• Review of key check values during key management functions
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
ISO 11568 Principle 7 & 8
“A key shall be replaced with a new key within the time
deemed feasible to determine the old key.”
“A key shall be replaced with a new key within the time
deemed feasible to perform a successful dictionary
attack on the data enciphered under the old key.”
• Demonstrable capability to replace keys
• Key replacement schedule
• Risk analysis
– NIST SP 800-57 provides guidance regarding factors to take into
account when determining the “Cryptoperiod”
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
ISO 11568 Principles 9, 10, 11
“A key shall cease to be used when its compromise is
known or suspected.”
“The compromise of a key shared among one group of
parties shall not compromise keys shared among any
other group of parties.”
“A compromised key shall not provide any information to
enable the determination of its replacement”
• Defined key compromise plans
• Demonstrable ability to change cryptographic keys
• Robust & segregated key hierarchy
• Non-deterministic key generation / replacement
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
ISO 11568 Principle 12
“A key shall only be loaded into a device when it may be
reasonably assured that the device is secure and has not
been subjected to unauthorised modification or
substitution.”
• HSM Acceptance procedures
• HSM Maintenance procedures
• Physical security controls
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Auditing Cryptographic Key Management
• Basic cryptographic mechanisms
• Importance of cryptographic controls
• Control objectives for cryptographic keys & Large-
scale Key Management in Financial Services
• Audit approach
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Audit approach
• Select & orient the audit team
• Understand the business
• Determine the primary risks
• Identify the primary controls
• Obtain evidence of design and operational
effectiveness
• Report
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Select & Orient the audit team
Suitably skilled & experienced
• Understanding of cryptographic controls
• Key Lifecycle awareness
• Understanding of control objectives for
cryptographic keys
• Familiar with Governance and business processes
• Familiarity with cryptographic hardware and
software in use
• Generally, good auditors
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Understand the business
• Obtain Security Policy & Standards
• Map roles & responsibilities across the
organisation
• Cryptographic usage register
• Cryptographic key inventory
• Operational procedures documents
• Output from Governance and risk processes
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Determine the primary risks
• Governance & Risk Management always of high
importance.
• Use ISO 11568 as a baseline
• Based on an understanding of your business,
select a subset of the risks to audit.
– By key usage
– By key management function
– By ISO 11568 objective
– By key lifecycle
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Determine the primary controls
• The primary controls that mitigate each risk
selected
Note: Given the dependence on centralised key
management operations, there is a requirement for
layered control. Each risk may have several layers
of controls. Therefore, do not underestimate the
time required to audit a key management function.
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Obtain evidence of design and operation of
controls
• Design of controls is likely to be easy as all key
management functions should be documented in
detail.
• Operation may be less easy as some functions,
such as key renewal, may be performed
infrequently.
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Auditing Cryptographic Key Management
Report
• Link control weaknesses identified back to
business impact. Difficult because:
– Controls are layered. Weaknesses in one does not
necessarily result in an immediate business impact.
– Business impact is not always immediately obvious.
– Tempting to document the worst case scenario
which may have low probability.
– Tempting to focus on fraud, when impact on
availability, reputational damage, regulatory
censure, cost of remediation may be more likely.
– Tempting to document impact as non-compliance
with ISO 11568
ISACA Northern Chapter meeting 19 October 2005
Auditing Cryptographic Key Management
Further Reading
• The Code Book, Simon Singh
• The music of the primes, Marcus du Sautoy
• Applied Cryptography, Bruce Schneier
• Practical Cryptography, Neils Ferguson & Bruce Schneier
• Users Guide to Cryptography and Standards, Alexander W Dent & Chris
J Mitchell
• Protocols for authentication and key establishment, Colin Boyd, Anish
Mathuria
• Understanding PKI, concepts, standards and deployment considerations,
Carlisle Adams and Steve Lloyd.
ISACA Northern Chapter meeting 19 October 2005
