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*3.2 Step 2. Append Length*

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RFC 1321

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3. MD5 Algorithm Description

**Prev:** 3.1 Step 1. Append Padding Bits

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### 3.2 Step 2. Append Length

3.2 Step 2. Append Length
A 64-bit representation of b (the length of the message before the
padding bits were added) is appended to the result of the previous
step. In the unlikely event that b is greater than 2^64, then only
the low-order 64 bits of b are used. (These bits are appended as two
32-bit words and appended low-order word first in accordance with the
previous conventions.)

At this point the resulting message (after padding with bits and with
b) has a length that is an exact multiple of 512 bits. Equivalently,
this message has a length that is an exact multiple of 16 (32-bit)
words. Let M[0 ... N-1] denote the words of the resulting message,
where N is a multiple of 16.

**Next:** 3.3 Step 3. Initialize MD Buffer

**Connected: An Internet Encyclopedia**

*3.2 Step 2. Append Length*