What is HV A and how do you use this function?

The HVA agent code is a method used to make messages unbreakable by converting letters into numbers and mixing them with a one‑time sequence of random digits.

How did the HVA Agent Code originate?

The HVA agent code was developed because the foreign intelligence service of the former GDR needed a completely secure way to send messages. They created a system that could be used easily by hand.

What is the HVA Agent Code?

First, each letter was converted into numbers using a substitution table. Then this row of numbers was mixed with a secret sequence of digits (a One‑Time Pad). This made the message even more secure and practically unbreakable.

The code remained in use until the end of the GDR in 1990. Later, the service also used a method where the order of letters in a table was shuffled to make decryption even harder for enemies.

The HV A Function in GC Wizard

In GC Wizard, this function can be found under: Coding and Codes → HV A

How does the function work?

The HVA tool is designed to encode or decode messages according to the historical method used by the GDR intelligence service.The tool follows a fixed process to convert text into a secure numeric code.

Input

The upper text field is used to enter the information.

  • When encoding, the readable text is typed here.
  • When decoding, the numeric code is entered here.

Settings

Encode / Decode

You can choose between two functions:

  • Encode – Converts readable text into a numeric code.
  • Decode – Converts a received numeric code back into text.
Time Period

The HVA used different substitution tables depending on the period.
Select the correct period for an accurate translation:

  • 1950–1970 – Early‑period table
  • 1970–1990 – Later‑period table
OTP Key

For maximum security, the One‑Time Pad option can be enabled.

When this option is active, an extra input field appears. Here you enter a sequence of random digits.
GC Wizard automatically groups the key into blocks of five digits for better readability.

Both sender and receiver must use exactly the same sequence of digits, otherwise the message cannot be read.

Output

The result is shown at the bottom of the screen.

  • When encoding, the final numeric sequence appears here.
  • When decoding, the original readable text is shown.

A copy button is displayed next to the result. This button copies the output to the clipboard.