Cryptographic apparatus with double feedforward hash function
US5606616A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 3, 1995 |
| Grant date | Feb 25, 1997 |
| Priority date | — |
| Expiry date | Jul 3, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L2209/125
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Apparatus is provided for authenticating information using a double feedforward hash function to provide complementarity in the implementation of an encryption algorithm. A cryptographic processor has a first input for receiving plaintext, a second input for receiving a key and an output for outputting ciphertext generated by cryptographically processing the plaintext and key. A first circuit element is responsive to the ciphertext and plaintext for outputting a first ciphertext derivative. A second circuit element is responsive to at least a portion of the first ciphertext derivative and the key for outputting a second ciphertext derivative. The first and second circuit elements can be XOR gates. Alternatively, these elements can be provided using lookup tables. Subsequent cryptographic processor stages can be provided having a first input for receiving second plaintext, a second input for receiving the second ciphertext derivative as a key, and an output for outputting second ciphertext generated by cryptographically processing the second plaintext and the second ciphertext derivative. In an illustrated embodiment, the cryptographic processor is a DES processor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.