Merge branch 'master' of git+ssh://metalzone.distorted.org.uk/~mdw/public-git/catacomb/

[u/mdw/catacomb] / catcrypt.1

diff --git a/catcrypt.1 b/catcrypt.1
index 56fe297..61da7f9 100644 (file)
--- a/catcrypt.1
+++ b/catcrypt.1
@@ -44,7 +44,7 @@ is one of:
 .RI [ item ...]
 .br
 .B encrypt
-.RB [ \-a ]
+.RB [ \-aC ]
 .RB [ \-k
 .IR tag ]
 .RB [ \-f
@@ -54,7 +54,7 @@ is one of:
 .RI [ file ]
 .br
 .B decrypt
-.RB [ \-aqv ]
+.RB [ \-aqvC ]
 .RB [ \-f
 .IR format ]
 .RB [ \-o
@@ -184,6 +184,16 @@ Use the
 algorithm of the
 .BR key (1))
 command to generate the key.
+.TP
+.B symm
+This is a simple symmetric encapsulation scheme.  It works by hashing a
+binary key with a randomly-generated salt.  Use the
+.B binary
+algorithm of the
+.B key add
+command (see
+.BR key (1))
+to generate the key.
 .PP
 As well as the KEM itself, a number of supporting algorithms are used.
 These are taken from appropriately named attributes on the key or,
@@ -335,6 +345,21 @@ algorithm of the
 command (see
 .BR key (1))
 to generate the key.
+.TP
+.B mac
+This uses a symmetric message-authentication algorithm rather than a
+digital signature.  The precise message-authentication scheme used is
+determined by the
+.B mac
+attribute on the key, which defaults to
+.IB hash -hmac
+if unspecified.  Use the
+.B binary
+algorithm of the
+.B key add
+command (see
+.BR key (1))
+to generate the key.
 .PP
 As well as the signature algorithm itself, a hash function is used.
 This is taken from the
@@ -470,6 +495,10 @@ in the current keyring; the default is not to sign the ciphertext.
 Write output to
 .I file
 rather than to standard output.
+.TP
+.B "\-C, \-\-nocheck"
+Don't check the public key for validity.  This makes encryption go much
+faster, but at the risk of using a duff key.
 .SS decrypt
 The
 .B decrypt
@@ -508,6 +537,11 @@ Write output to
 instead of to standard output.  The file is written in binary mode.
 Fixing line-end conventions is your problem; there are lots of good
 tools for dealing with it.
+.TP
+.B "\-C, \-\-nocheck"
+Don't check the private key for validity.  This makes decryption go much
+faster, but at the risk of using a duff key, and possibly leaking
+information about the private key.
 .PP
 Output is written to standard output in a machine-readable format.
 Major problems cause the program to write a diagnostic to standard error
@@ -676,8 +710,9 @@ Use the first bits of the keystream to key a symmetric encryption
 scheme; use the next bits to key a message authentication code.
 .hP 4.
 If we're signing the message then extract 1024 bytes from the keystream,
-sign them, and emit a packet containing the signature.  The signature
-packet doesn't contain the signed message, just the signature.
+sign the header and public value, and the keystream bytes; emit a packet
+containing the signature.  The signature packet doesn't contain the
+signed message, just the signature.
 .hP 5.
 Split the message into blocks.  For each block, pick a random IV from
 the keystream, encrypt the block and emit a packet containing the