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authorMatt Caswell <matt@openssl.org>2019-04-18 10:54:58 +0100
committerMatt Caswell <matt@openssl.org>2019-04-19 09:37:47 +0100
commit6f3aae256d62cfcc48c07cc0ead5080b070f371b (patch)
treeb56ceff6bc55ffa89377e1a24a0dd627e9cbf449
parent6caf7f3aec5484ee65067e9671299d3411565dc1 (diff)
Clarify the documentation on the use of ChaCha20
Reviewed-by: Tim Hudson <tjh@openssl.org> (Merged from https://github.com/openssl/openssl/pull/8780)
-rw-r--r--doc/man3/EVP_chacha20.pod10
1 files changed, 9 insertions, 1 deletions
diff --git a/doc/man3/EVP_chacha20.pod b/doc/man3/EVP_chacha20.pod
index 7b014c2675..5218ee215f 100644
--- a/doc/man3/EVP_chacha20.pod
+++ b/doc/man3/EVP_chacha20.pod
@@ -21,7 +21,15 @@ The ChaCha20 stream cipher for EVP.
=item EVP_chacha20()
-The ChaCha20 stream cipher. The key length is 256 bits, the IV is 96 bits long.
+The ChaCha20 stream cipher. The key length is 256 bits, the IV is 128 bits long.
+The first 32 bits consists of a counter in little-endian order followed by a 96
+bit nonce. For example a nonce of:
+
+000000000000000000000002
+
+With an initial counter of 42 (2a in hex) would be expressed as:
+
+2a000000000000000000000000000002
=item EVP_chacha20_poly1305()