iPXE

X25519 multiplication step 3 result. More...
X25519 multiplication step 3 result.
Step 3 of X25519 multiplication is to multiply the highorder 11 bits from step 2 with the 6bit reduction constant 38, and to add this to the loworder 256 bits from step 2.
The multiplication inputs are limited to 11 and 6 bits respectively, and so the product will have at most 17 bits. After adding the loworder 256 bits from step 2, the result will have at most 257 bits.