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How did electronic cipher machines improve on mechanical rotor machines after World War II?

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A Vigenere cipher table displays the alphabet in both the top row and left column, with rows shifted to create a grid for encryption and decryption. Highlighted letters illustrate how to use the table. An explanation and example using the words cipher, key, and plaintext appears to the right. — cryptology In encrypting plaintext, the cipher letter is found at the intersection of the column headed by the plaintext letter and the row indexed by the key letter. To decrypt ciphertext, the plaintext letter is found at the head of the column determined by the intersection of the diagonal containing the cipher letter and the row containing the key letter.

Following World War II, electronic cipher machines were developed by adapting technology originally created for radar and digital computers.1

The primary improvement offered by these early electronic machines was a significant increase in the speed of operation compared to their mechanical predecessors. In their initial iterations, these devices functioned similarly to mechanical rotor machines, but they replaced physical rotors with electronically realized substitutions.1

Despite this advancement in speed, these early electronic machines inherited several limitations from the mechanical era, including:
* Cryptanalytic weaknesses: They retained the same fundamental vulnerabilities found in mechanical rotor machines.1
* Design constraints: They continued to rely on the principle of cyclically shifting simple substitutions to achieve more complex product substitutions.1

It was not until later, with the integration of advanced microcircuitry and nonlinear feedback logic, that cryptographers were able to overcome the security problems associated with the linear logic of earlier machines. These later developments eventually led to the creation of highly sophisticated systems, such as the Data Encryption Standard.21