Chapter 14 - 03 - Discuss Various Hash Functions and Cryptography Tools - 02_ocred_fax_ocred.pdf

Certified Cybersecurity Technician Exam 212-82 Cryptography HMAC The hash-based message authentication code (HMAC) is a type of message authentication cod...

Certified Cybersecurity Technician Exam 212-82 Cryptography HMAC The hash-based message authentication code (HMAC) is a type of message authentication code (MAC) that makes use of a cryptographic key in combination with a cryptographic hash function EEEEEN This algorithm includes an embedded hash function such as SHA-1 or MD5 The strength of HMAC depends on the embedded hash function, key size, and the size of the hash output As the HMAC executes the underlying hash function twice, it protects the data from various length extension attacks HMAC Hash-based message authentication code (HMAC) is a type of message authentication code (MAC) that uses a cryptographic key along with a cryptographic hash function. It is widely used to verify the integrity of data and authentication of a message. This algorithm includes an embedded hash function such as SHA-1 or MDS5. The strength of HMAC depends on the embedded hash function, key slize, and size of the hash output. HMAC includes two stages for computing the hash. The input key is processed to produce two keys, namely the inner key and the outer key. The first stage of the algorithm inputs the inner key and message to produce an internal hash. The second stage of the algorithm inputs the output from the first stage and outer key and produces the final HMAC code. As HMAC executes the underlying hash function twice, it offers protection against various length extension attacks. The size of the key and the output depends on the embedded hash function, e.g., 128 or 160 bits in the case of MD5 or SHA-1, respectively. Module 14 Page 1676 EG-Council Certified Cybersecurity Technician Copyright © by EG-Gouncil All Rights Reserved. Reproduction is Strictly Prohibited. Certified Cybersecurity Technician Exam 212-82 Cryptography Modes of Authenticated Encryption o| — QO Modes of authenticated encryption ensure the integrity and confidentiality of transmitted 0O.'_ == messages and rectifies the problem of chosen ciphertext attacks e——— Authenticated Encryption with Message IMlessage :' Authenticated Encryption with Authentication Code (IVIAC) (IMIAC) i' Associated Data (AEAD) » The message authentication code (MAC) is a » AEAD is another approach used to ensure the value obtained by hashing a plaintext v integrity and authenticity of a message message using a shared secret key » This approach adds additional data to the = Encrypt-then-MAC (EtM) : ciphertext at certain places to thwart chosen ciphertext attacks = Encrypt-and-MAC (E&M) ** MAC-then-encrypt (MtE) MAC-then-encrypt (MtE) % E i_ ¢¢ Copyright © by E.L All Rights Reserved. ReproductionIs Strictly Prohibited. Prohibited Modes of Authenticated Encryption Authenticated encryption (AE) modes of operation provide integrity and confidentiality for a transmitted message. In any cipher mode of operation, encryption/decryption is possible only with the shared secret key, preventing man-in-the-middle (MITM) attacks. However, the attacker can perform a chosen ciphertext attack to crack the encryption schema. The AE schema rectifies the problem of chosen cipher attacks. In AE modes, the ciphertext is combined with a message authentication code (MAC). Therefore, choosing a part in the ciphertext is not possible, and the AE scheme rejects improper ciphertexts while decrypting. Authenticated encryption with Message Authentication Code (MAC) A MAC is a value obtained by hashing a plaintext message using a shared secret key. It provides integrity for the message, and the receiver can verify the message using the hash value attached to it. The following are the three different ways of using a MAC while encrypting a message. = Encrypt-then-MAC (EtM) In this approach, the plaintext is first encrypted using a secret key. For the obtained ciphertext, a hash value called message authentication code (MAC) is generated. The MAC is attached to the ciphertext and transmitted. This approach provides higher security for the transmitted message than other AE approaches. * Encrypt-and-MAC (E&M) In the E&M approach, a MAC is first generated for the plaintext, following which the plaintext is encrypted using a secret key. Finally, both the ciphertext and MAC are combined and transmitted. Module 14 Page 1677 Certified Cybersecurity Technician Copyright © by EG-Council All Rights Reserved. Reproduction is Strictly Prohibited. Certified Cybersecurity Technician Exam 212-82 Cryptography = MAC-then-encrypt (MtE) In the MtE approach, a MAC is first generated for the plaintext using the hash function, and the MAC is combined with the plaintext. The combination of the plaintext and MAC is encrypted with a secret key to produce ciphertext. The ciphertext contains the encrypted MAC. Authenticated Encryption with Associated Data (AEAD) AEAD is another approach used to ensure the integrity and authenticity of a message that contains both encrypted and unencrypted data. This approach adds additional data to the ciphertext at certain places to thwart chosen ciphertext attacks. The message header is kept unencrypted so that the receiver can verify the source of the message, and the payload is encrypted to ensure confidentiality. Module 14 Page 1678 Certified Cybersecurity Technician Copyright © by EG-Council All Rights Reserved. Reproduction is Strictly Prohibited. Certified Cybersecurity Technician Exam 212-82 Cryptography IMDS5 and MD6 MDS5 Hash Calculators MDS DS Calculator - MD6 Hash Generator 0 06 MDS Calculator 2 MDS - X https://www.browserling.com https://www.browserling.com - — T File Tool: Tools Help Fie Name : [|CCTsers A Desktco \Users\Admin' maseaic(1 Deaktcp'md Scaic(1 00 0.0) 0.0) mama |]. v=0 w , = (G ] All Hash Generator OO0 Lo ] ' https://www.browserling.com https://www.browserling.com MDS Digest MD5 Digest Compare Compare To To ‘ ‘ [Frrtitecdecatsitenicesia [543a8108cdecab 05186771 Tec 5ot | | ] _A_. ][[] Upper cae case B. (2] Mashityfiles [£] MashAtyFiles -- MD6 Hash Generator 0Q Xb4 https://convert-tool.com https://convert-tool.com Fde Edt View Optons Help e — |= - hitps.//www. builzip.com htps//www. bullzip.com VTNaouwdS 0 | LB - lfl NN A* Fiename Flename D5 MD5 SHAY SHAY cren CRCR A|~ £13076-6123-1-SMpat =] 3076-6123-1-SM paf |437T10¢et9 11129457 0eafe3ba0bES! 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