* From http://eprint.iacr.org/2010/264.pdf:
*
* The scheme HKDF is specifed as:
- * HKDF(XTS, SKM, CTXinfo, L) = K(1) || K(2) || ... || K(t)
+ * HKDF(XTS, SKM, CTXinfo, L) = K(1) || K(2) || ... || K(t)
* where the values K(i) are defined as follows:
- * PRK = HMAC(XTS, SKM)
- * K(1) = HMAC(PRK, CTXinfo || 0);
- * K(i+1) = HMAC(PRK, K(i) || CTXinfo || i), 1 <= i < t;
+ * PRK = HMAC(XTS, SKM)
+ * K(1) = HMAC(PRK, CTXinfo || 0);
+ * K(i+1) = HMAC(PRK, K(i) || CTXinfo || i), 1 <= i < t;
* where t = [L/k] and the value K(t) is truncated to its first d = L mod k bits;
* the counter i is non-wrapping and of a given fixed size, e.g., a single byte.
* Note that the length of the HMAC output is the same as its key length and therefore
* @param string $ikm The input keying material
* @param string $salt The salt to add to the ikm, to get the prk
* @param string $info Optional context (change the output without affecting
- * the randomness properties of the output)
+ * the randomness properties of the output)
* @param int $L Number of bytes to return
* @return string Cryptographically secure pseudorandom binary string
*/