Szilárd Pfeiffer
A free software fanatic developer, a security commited engineer, a free-culture enthusiastic jounalist, an agile believer manager.
A titkosítás elméletének gyakorlata
Bob
Craig, Eve, Mallory, Sybil, Trudy, ...
Alice
Symmetric-key algorithms
Hash algorithms
#
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Public-key algorithms
Digital signature
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WoT vs. PKI
Grades
TLS Protocols
TLS Protocols
ssl.use-sslv2 = "disable" ...
Lighttpd
ssl_protocols TLSv1.2 TLSv1.3;
Nginx
SSLProtocol +TLSv1.2 +TLSv1.3
Apache
!TLSv1.1 !TLSv1.0 !TLSv1 !SSLv2 !SSLv3
Cipher Suites
TLS
protocol
_ECDHE
_RSA
_AES_128_CBC
_SHA256
key exchange
authentication
symmetric cipher
MAC
ECDHE-RSA-AES128-SHA256
Key Exchange
-
Forward Secrecy
-
ephemeral
-
static
-
-
Key Strength
-
Session Resumption
-
session id
-
session ticket
-
Forward Secrecy
ephemeral
static
Diffie–Hellman
(DH)
Rivest–Shamir–Adleman
(RSA)
Elliptic-curve
Diffie–Hellman
(ECDH)
Elliptic-curve
Diffie–Hellman Ephemeral
(ECDHE)
Diffie-Hellman Ephemeral
(DHE)
Forward Secrecy
Exchange Strength
Session Resumption
- perfect forward secrecy
- stateful vs. stateless
- stored cryptographic parameters
- unencrypted sending
- speed
- real time
- CPU time
Authentication
- Key types
- Digital Signature Algorithm (DSA)
- Rivest–Shamir–Adleman (RSA)
- Elliptic Curve DSA (ECDSA)
- Key sizes
- Signature algorithms
Key Sizes
Signature Algorithm
Bulk Cipher
- Stream Cipher
-
Block Cipher
-
secure
-
insecure
-
unused
-
-
Block Cipher Mode
Stream Cipher
secure
insecure
Rivest Cipher 4
(ARCFOUR/RC4)
ChaCha
(ChaCha20)
Rivest Cipher 4
Block Cipher
secure
insecure
Block Size of 64 bits
(DES, 3DES, GHOST, IDEA, RC2)
Advanced Encryption Standard
(AES128, AES256)
CBC mode only
(SEED)
unused
Far East
(ARIA, Camellia)
Block Cipher Mode
authenticated
not authenticated
Cipher Block Chaining
(CBC)
Galois/Counter Mode
(GCM)
Counter with CBC-MAC
(CCM/CCM-8)
MAC
-
MAC types
-
HMAC
-
UMAC
-
-
MAC algorithms
MAC types
universal hashing
has based
Message-Digest Algorithm 5
(MD5)
Poly1305
(POLY1305)
Secure Hash Algorithm 2
(SHA256, SHA384)
Secure Hash Algorithm 1
(SHA-1)
MAC algorithms
secure
collisions
Message-Digest Algorithm 5
(MD5)
Poly1305
(POLY1305)
Secure Hash Algorithm 2
(SHA256, SHA384)
Secure Hash Algorithm 1
(SHA-1)
Cipher Settings
-
cipher suites
-
explicit list
-
list operations
-
-
cipher preference
Cipher Suites
ssl.cipher-list = "CipherSuiteString"
Lighttpd
ssl_ciphers CipherSuiteString
Nginx
SSLCipherSuite CipherSuiteString
Apache
HIGH:!PSK:!SRP:!aNULL:!aDSS:!kRSA:!ARIA:!CAMELLIA:!SHA:!AESCCM
Cipher Preference
honor-cipher-order = "enable"
Lighttpd
ssl_prefer_server_ciphers On;
Nginx
SSLHonorCipherOrder On
Apache
Always On
Revocation Check
-
Certificate Revocation List
-
Online Certificate Status Protocol
-
Responders
-
Stapling
-
-
Certificate validity period
Revocation Check
Location
CRL
✗
Access
Size
✗
✗
OCSP
✗
✗
✓
Privacy
✗
✓
OCSP Stapling
✓
✓
✓
✓
Full Chain
✗
✓
✓
OCSP Multi Stapling
✓
✓
✓
✓
✓
?
Support
✓
✓
✓
Hack proof
✗
✗
✗
✗
OCSP Stapling
OCSP Stapling
-
Lighttpd
ssl_stapling on;
Nginx
SSLUseStapling on
Apache
Should Be On
Certificate Transparency
- transparent
- append-only
- cryptographically assured
- reproducible
- publicly monitorable and auditable
- log
TLS 1.3
-
Key Exchange
- Authentication
- Bulk Cipher
- Hash Algorithm
-
Session Resumption
-
Revocation Check
-
Performance
-
Support
Key Exchange
ephemeral
static
Diffie–Hellman
(DH)
Rivest–Shamir–Adleman
(RSA)
Elliptic-curve
Diffie–Hellman
(ECDH)
Elliptic-curve
Diffie–Hellman Ephemeral
(ECDHE)
Diffie-Hellman Ephemeral
(DHE)
Authentication
secure
insecure
anonymous
(NULL)
Rivest–Shamir–Adleman
(RSA)
Elliptic Curve
Digital Signature Algorithm
(ECDSA)
Digital Signature Algorithm
(DSA)
Edwards-Curve
Digital Signature Algorithm
(EdDSA)
unused
Stream Cipher
secure
insecure
Rivest Cipher 4
(ARCFOUR/RC4)
ChaCha
(ChaCha20)
Block Cipher
secure
insecure
Block Size of 64 bits
(DES, 3DES, GHOST, IDEA, RC2)
Advanced Encryption Standard
(AES128, AES256)
CBC mode only
(SEED)
unused
Far East
(ARIA, Camellia)
Block Cipher Mode
authenticated
not authenticated
Cipher Block Chaining
(CBC)
Galois/Counter Mode
(GCM)
Counter with CBC-MAC
(CCM/CCM-8)
MAC
secure
collisions
Message-Digest Algorithm 5
(MD5)
Poly1305
(POLY1305)
Secure Hash Algorithm 2
(SHA256, SHA384)
Secure Hash Algorithm 1
(SHA-1)
Cipher Suites
-
TLS_AES_256_GCM_SHA384 -
TLS_AES_128_GCM_SHA256
-
TLS_AES_128_CCM_SHA256 -
TLS_AES_128_CCM_8_SHA256
-
TLS_CHACHA20_POLY1305_SHA256
Revocation Check
-
Certificate Revocation List
-
Online Certificate Status Protocol
-
Responders
-
Stapling
-
Session Resumption
PFS
obsolated
session resumption
(session id)
session resumption without server-side state
(session ticket)
non PFS
static pre-shared-key
(PSK_KE)
ephemeral pre-shared-key
(PSK_DHE_KE)
Performance
-
Handshake
-
Resumption
-
Application layer
Support
library
browser
Most popular
(Chrome/Chromium, Firefox)
Less popular
(Apple, Edge)
server
CDN
Most popular
(Apache, NGINX)
Less popular
(IIS, Lighty)
Most popular
(Cloudflare, KeyCDN)
Most popular
(OpenSSL, GnuTLS)
Less popular
(Boring SSL, Fizz)
HTTPS
-
Automatic Redirection to HTTPS
- HSTS Preload
-
Security Headers
Secure Headers
-
Automatic Redirect to HTTPS
-
Public Key Pinning
-
Defense against
-
Clickjacking
-
Content Injection Attacks
-
Cross-site scripting
-
HTTP STS
setenv.add-response-header=("Strict-Transport-Security"=>"Value")
Lighttpd
add_header Strict-Transport-Security 'Value' always;
Nginx
Header always set Strict-Transport-Security "Value"
Apache
max-age=63072000; includeSubdomains;
preload
HTTP STS
HTTP Public Key Pinning
setenv.add-response-header=("Public-Key-Pins"=>"Value")
Lighttpd
add_header Public-Key-Pins 'Value' always;
Nginx
Header always set Public-Key-Pins "Value"
Apache
pin-sha256="GRAH5Ex+kB4cCQi5gMU82urf...";
report-uri="https://example.com/report/hpkp";
max-age=15768000;
includeSubDomains
Expect Staple
setenv.add-response-header=("Expect-Staple"=>"Value")
Lighttpd
add_header Expect-Staple 'Value' always;
Nginx
Header always set Expect-Staple "Value"
Apache
max-age=31536000;
report-uri="https://example.com/report/staple";
includeSubDomains;
preload
Expect CT
setenv.add-response-header=("Expect-Staple"=>"Value")
Lighttpd
add_header Expect-Staple 'Value' always;
Nginx
Header always set Expect-Staple "Value"
Apache
max-age=31536000;
report-uri="https://example.com/report/staple";
enforce
Clickjacking
setenv.add-response-header=("X-Frame-Options"=>"Value")
Lighttpd
add_header X-Frame-Options "Value" always;
Nginx
Header always set X-Frame-Options "Value"
Apache
deny/sameorigin
XSS Protection
setenv.add-response-header=("X-XSS-Protection"=>"Value")
Lighttpd
add_header X-XSS-Protection "Value" always;
Nginx
Header always set X-XSS-Protection "Value"
Apache
X-XSS-Protection: 1; mode=block
Feature Policy
setenv.add-response-header=("Feature-Policy"=>"Value")
Lighttpd
add_header Feature-Policy "Value" always;
Nginx
Header always set Feature-Policy "Value"
Apache
microphone 'none';
geolocation ''*'';
payment 'self';
...
Content Security Policy
setenv.add-response-header=("Content-Security-Policy"=>"Value")
Lighttpd
add_header Content-Security-Policy "Value" always;
Nginx
Header always set Content-Security-Policy "Value"
Apache
default-src https://same.domain:443
Application Protocols
Tools
-
Online checkers
-
Offline checkers
- TLS offloaders
Online Checkers
-
Transport Layer Security
-
Security Headers
Offline Checkers
TLS offloaders
Questions?
A titkosítás elméletének gyakorlata
A titkosítás elméletének gyakorlata
By Szilárd Pfeiffer
A titkosítás elméletének gyakorlata
- 1,151
