Blog Entry (c) Monday, February 24, 2026, by James Pate Williams, Jr. TDES Verification

I wrote my Triple-DES C source code a number of years ago. Today, I verified my Cipher Block Chaining version using the NIST online reference document:

Click to access TDES_CBC.pdf

CBC-TDES (Encryption)

Key1 is
        01234567 89ABCDEF
Key2 is
        23456789 ABCDEF01
Key3 is
        456789AB CDEF0123
IV is
        F69F2445 DF4F9B17

Block #1
Plaintext       6BC1BEE2 2E409F96
InputBlock      9D5E9AA7 F10F0481
OutputBlock     2079C3D5 3AA763E1
Ciphertext      2079C3D5 3AA763E1

Block #2
Plaintext       E93D7E11 7393172A
InputBlock      C944BDC4 493474CB
OutputBlock     93B79E25 69AB5262
Ciphertext      93B79E25 69AB5262

Block #3
Plaintext       AE2D8A57 1E03AC9C
InputBlock      3D9A1472 77A8FEFE
OutputBlock     51657048 1F25B50F
Ciphertext      51657048 1F25B50F

Block #4
Plaintext       9EB76FAC 45AF8E51
InputBlock      CFD21FE4 5A8A3B5E
OutputBlock     73C0BDA8 5C8E0DA7
Ciphertext      73C0BDA8 5C8E0DA7

CBC-TDES (Decryption)

Key1 is
        01234567 89ABCDEF
Key2 is
        23456789 ABCDEF01
Key3 is
        456789AB CDEF0123
IV is
        F69F2445 DF4F9B17

Block #1
Ciphertext      2079C3D5 3AA763E1
InputBlock      2079C3D5 3AA763E1
OutputBlock     9D5E9AA7 F10F0481
Plaintext       6BC1BEE2 2E409F96
Block #2
Ciphertext      93B79E25 69AB5262
InputBlock      93B79E25 69AB5262
OutputBlock     C944BDC4 493474CB
Plaintext       E93D7E11 7393172A
Block #3
Ciphertext      51657048 1F25B50F
InputBlock      51657048 1F25B50F
OutputBlock     3D9A1472 77A8FEFE
Plaintext       AE2D8A57 1E03AC9C
Block #4
Ciphertext      73C0BDA8 5C8E0DA7
InputBlock      73C0BDA8 5C8E0DA7
OutputBlock     CFD21FE4 5A8A3B5E
Plaintext       9EB76FAC 45AF8E51

D:\Triple_DES_CBC\Triple_DES_CBC\Release\Triple_DES_CBC.exe (process 43728) exited with code 0 (0x0).
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Author: jamespatewilliamsjr

My whole legal name is James Pate Williams, Jr. I was born in LaGrange, Georgia approximately 70 years ago. I barely graduated from LaGrange High School with low marks in June 1971. Later in June 1979, I graduated from LaGrange College with a Bachelor of Arts in Chemistry with a little over a 3 out 4 Grade Point Average (GPA). In the Spring Quarter of 1978, I taught myself how to program a Texas Instruments desktop programmable calculator and in the Summer Quarter of 1978 I taught myself Dayton BASIC (Beginner's All-purpose Symbolic Instruction Code) on LaGrange College's Data General Eclipse minicomputer. I took courses in BASIC in the Fall Quarter of 1978 and FORTRAN IV (Formula Translator IV) in the Winter Quarter of 1979. Professor Kenneth Cooper, a genius poly-scientist taught me a course in the Intel 8085 microprocessor architecture and assembly and machine language. We would hand assemble our programs and insert the resulting machine code into our crude wooden box computer which was designed and built by Professor Cooper. From 1990 to 1994 I earned a Bachelor of Science in Computer Science from LaGrange College. I had a 4 out of 4 GPA in the period 1990 to 1994. I took courses in C, COBOL, and Pascal during my BS work. After graduating from LaGrange College a second time in May 1994, I taught myself C++. In December 1995, I started using the Internet and taught myself client-server programming. I created a website in 1997 which had C and C# implementations of algorithms from the "Handbook of Applied Cryptography" by Alfred J. Menezes, et. al., and some other cryptography and number theory textbooks and treatises.

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