Geffe Generator
- Tags
- cryptography
A stream cipher which [see page 26, multiplexes] 3 other input stream.
The Geffe generator uses:
| Term | Description |
|---|---|
| \( j \) | The current bit index in the output stream |
| \( d_j \) | \(\text{LSFR}_1\) The selector-stream |
| \( e_j \) | \(\text{LSFR}_2\) |
| \( f_j \) | \(\text{LSFR}_3\) |
| \( b_j = (d_j \land e_j) \xor ((\neg d_j) \and f_j) \) |
The gaffe generator has the following [see page 27, properties]:
- 75% percent of the time output \( b \) agrees with input \( e \).
- 75% percent of the time output \( b \) agrees with input \( f \).
- The output \( b \) agrees with \( d \) 50% of the time.