1 files changed, 52 insertions, 0 deletions
diff --git a/doc/sha.doc b/doc/sha.doc
new file mode 100644
index 0000000000..895fa182ed
--- /dev/null
+++ b/doc/sha.doc
@@ -0,0 +1,52 @@
+The SHA (Secure Hash Algorithm) library.
+SHA is a message digest algorithm that can be used to condense an arbitrary
+length message down to a 20 byte hash.  The functions all need to be passed
+a SHA_CTX which is used to hold the SHA context during multiple SHA_Update()
+function calls.  The normal method of use for this library is as follows
+This library contains both SHA and SHA-1 digest algorithms.  SHA-1 is
+an update to SHA (which should really be called SHA-0 now) which
+tweaks the algorithm slightly.  The SHA-1 algorithm is used by simply
+using SHA1_Init(), SHA1_Update(), SHA1_Final() and SHA1() instead of the
+SHA*() calls
+
+SHA_Init(...);
+SHA_Update(...);
+...
+SHA_Update(...);
+SHA_Final(...);
+
+This library requires the inclusion of 'sha.h'.
+
+The functions are as follows:
+
+void SHA_Init(
+SHA_CTX *c);
+	This function needs to be called to initiate a SHA_CTX structure for
+	use.
+	
+void SHA_Update(
+SHA_CTX *c;
+unsigned char *data;
+unsigned long len);
+	This updates the message digest context being generated with 'len'
+	bytes from the 'data' pointer.  The number of bytes can be any
+	length.
+
+void SHA_Final(
+unsigned char *md;
+SHA_CTX *c;
+	This function is called when a message digest of the data digested
+	with SHA_Update() is wanted.  The message digest is put in the 'md'
+	array and is SHA_DIGEST_LENGTH (20) bytes long.
+
+unsigned char *SHA(
+unsigned char *d;
+unsigned long n;
+unsigned char *md;
+	This function performs a SHA_Init(), followed by a SHA_Update()
+	followed by a SHA_Final() (using a local SHA_CTX).
+	The resulting digest is put into 'md' if it is not NULL.
+	Regardless of the value of 'md', the message
+	digest is returned from the function.  If 'md' was NULL, the message
+	digest returned is being stored in a static structure.
+