# RFC Errata

### RFC 4634, "US Secure Hash Algorithms (SHA and HMAC-SHA)", July 2006

**Note: This RFC has been obsoleted by RFC 6234**

Area Assignment: sec

Errata ID: 2412

**Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT**

Reported By: Alfred Hoenes

Date Reported: 2006-08-13

Held for Document Update by: Sean Turner

Date Held: 2010-08-06

Section 3 says:

Section 3 of RFC 4634, on page 5, defines the elementary word operations to be used subsequently in the text, including the left shift operation, '<<'. Unfortunately, the right shift operation '>>' is used frequently as well, but not defined in Section 3. I propose to amend the second paragraph of Section 3, on page 5, In the operations below, x<<n is obtained as follows: discard the left-most n bits of x and then pad the result with n zeroed bits on the right (the result will still be the same number of bits).

It should say:

to read: In the operations below, x<<n is obtained as follows: discard the left-most n bits of x and then pad the result with n zeroed bits on the right (the result will still be the same number of bits). | Similarly, x>>n is obtained as follows: discard the right-most n bits | of x and then prepend the result with n zeroed bits on the left (the | result will still be the same number of bits).