WTLS (Wireless Transport Layer Security) Youngho Choung
Youngho Choung Contents Why we need WTLS? What is WTLS? What is TLS (SSL3.0) ? WTLS Functions Security Algorithm WTLS specifications Other Technologies
Youngho Choung Why we need WTLS ? (1/2) What can we do through the Cell Phone? Communication Using Internet E-commerce On-line banking Trading Stock Electric Cash Electric ID Watching movie, take a picture … etc …
Youngho Choung Why we need WTLS ? (2/2) Environment problems We need Security Solutions
Youngho Choung What is WTLS ? (1/2)
Youngho Choung What is WTLS ? (1/2)
Youngho Choung What is TLS (SSL3.0) ? (1/3) TLS stand for Transaction Layer Security SSL stand for Secure Socket Layer Customer 웹 브 라 우 저 인터넷 Internet Shopping Mall 불안전한 Unreliable Channel 암호화구간
Youngho Choung What is TLS (SSL3.0) ? (2/3) Application data Fragment Compress Add MAC Encrypt Append SSL record header SSL Handshake Protocol SSL Change Cipher Spec Protocol SSL Alert Protocol HTTP SSL Record Protocol TCP IP
Youngho Choung What is TLS (SSL3.0) ? (3/3) Handshake protocol K ey establishment algorithm Diffie-Hellman, RSA, Fortezza Certificate RSA, DSS,Fortezza Record protocol MAC algorithm MD5, SHA-1 Encryption algorithm RC2, RC4, DES, Triple DES, IDEA,Fortezza
Youngho Choung WTLS Functions Data Integrity Privacy Authentication DoS (Denial of Service) protection Optional
Youngho Choung Security Algorithm Hash Function Dyejsmldmnf mdfnmd,sdd fnfnfnlkfekkfe ekfkjefjefelfee Any Length Plain Text Hash Function Fix length Encrypted Text MD5, MD4, Hash, SHA-1, etc
Youngho Choung Security Algorithm Block Cipher (1)Diagram M E C (Message) (Ciphertext) K (Key) M, C, K : nbit blocks Examples ( in bits) {128,192,256} AES 64 DES KCM
Youngho Choung Security Algorithm Block Cipher (2)Encryption : Combination ofSubstitution& Permutation Decryption : Inverse of Encryption (3) Classical ciphers a.Permutation Ciphers b.Substitution Cipher : Caesar Cipher
Youngho Choung Security Algorithm Public Key Key distribution is difficult Tow Communicants already share a key or have the use of a key distribution center Characteristic (public) encryption key ≠ (private) decryption key
Youngho Choung Security Algorithm Public Key
Youngho Choung WTLS Specifications (1/5) Handshaking protocol Full handshaking protocol Abbreviated handshaking protocol Optimized handshaking protocol Alert protocol Change Cipher spec protocol Record protocol
Youngho Choung WTLS Specifications Full handshaking
Youngho Choung WTLS Specifications Abbreviated handshaking
Youngho Choung WTLS Specifications Optimized full handshaking [ChangCipherSpec] Finished Application Data ServerHello Certificate [ChangeCipherSpec] Finished
Youngho Choung WTLS Specifications (4/5) Alert protocol Change Cipher spec protocol
Youngho Choung WTLS Specifications (5/5) Record Protocol
Youngho Choung Let ’ s talk about …… later.. Let ’ s talk about …… later.. WALS(Wireless Application Layer Security) WPKI(Wireless Public-Key Infrastructure) WIM(WAP Identity Module References