Hawkynt

DES-X

DES with key whitening by Ron Rivest (1984). Uses 64-bit pre/post-whitening keys with standard DES to increase resistance to brute-force attacks. Educational implementation showing key whitening techniques.

Properties

Property	Value
Category	Block Ciphers
Sub-category	Block Cipher
Security status	❌ Broken
Complexity	Intermediate
Inventor	Ronald L. Rivest
Year	1984
Origin	🇺🇸 United States
Source	algorithms/block/des-x.js

Parameters

Parameter	Supported values
Key sizes	24 bytes (192 bits)
Block sizes	8 bytes (64 bits)

Security

Status: ❌ Broken

Known vulnerabilities

Issue	Description	Mitigation
Based on DES	DES-X inherits all weaknesses of DES including small key size and susceptibility to differential cryptanalysis	Use modern block ciphers like AES instead of DES-X
Key whitening limitations	While key whitening increases security, it doesn’t address fundamental DES weaknesses	DES-X is obsolete - use AES or other modern ciphers

Documentation

• DES-X Original Specification
• RSA BSAFE DES-X Documentation
• Applied Cryptography - DES-X

References

• Crypto++ DES-X Implementation
• Key Whitening in Block Ciphers
• DES-X Security Analysis

Test vectors

5 vectors ship with this algorithm and run in the test suite. Byte values are hexadecimal.

Vector 1 — DES-X all-zero key and block (degenerates to the DES all-zero known answer)

Field	Value
key	000000000000000000000000000000000000000000000000
input	0000000000000000
expected	8ca64de9c1b123a7

Vector 2 — OpenSSL DES_xcbc_encrypt known answer, block 1

Field	Value
key	f1e0d3c2b5a497860123456789abcdeffedcba9876543210
input	c9ea8fac45660330
expected	846b2914851e9a29

Vector 3 — OpenSSL DES_xcbc_encrypt known answer, block 2

Field	Value
key	f1e0d3c2b5a497860123456789abcdeffedcba9876543210
input	ca045e34ec6dba5d
expected	54732f8aa0a611c1

Vector 4 — OpenSSL DES_xcbc_encrypt known answer, block 3

Field	Value
key	f1e0d3c2b5a497860123456789abcdeffedcba9876543210
input	3c160ffec9cb74e1
expected	15cdc2d7951b1053

Vector 5 — OpenSSL DES_xcbc_encrypt known answer, block 4

Field	Value
key	f1e0d3c2b5a497860123456789abcdeffedcba9876543210
input	73a2b0f7951b1053
expected	a63c5e03b21aa3c4

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