1 files changed, 29 insertions, 11 deletions
diff --git a/system/scrypt/README b/system/scrypt/README
index 90be1eb4e0..1e17314d7e 100644
--- a/system/scrypt/README
+++ b/system/scrypt/README
@@ -1,11 +1,29 @@
-The scrypt key derivation function was originally developed for use in the
-Tarsnap online backup system and is designed to be far more secure against
-hardware brute-force attacks than alternative functions such as PBKDF2 or
-bcrypt.
-
-This simple password-based encryption utility is available as a demonstration
-of the scrypt key derivation function. On modern hardware and with default
-parameters, the cost of cracking the password on a file encrypted by scrypt
-enc is approximately 100 billion times more than the cost of cracking the same
-password on a file encrypted by openssl enc; this means that a five-character
-password using scrypt is stronger than a ten-character password using openssl.
+The scrypt key derivation function was originally developed for use in
+the Tarsnap online backup system and is designed to be far more secure
+against hardware brute-force attacks than alternative functions such as
+PBKDF2 or bcrypt.
+
+A simple password-based encryption utility is available as a
+demonstration of the scrypt key derivation function. On modern hardware
+and with default parameters, the cost of cracking the password on a file
+encrypted by scrypt enc is approximately 100 billion times more than the
+cost of cracking the same password on a file encrypted by openssl enc;
+this means that a five-character password using scrypt is stronger than
+a ten-character password using openssl.
+
+In addition to the scrypt command-line utility, a development library
+libscrypt-kdf can be built and installed by setting the LIB environment
+variable: LIB=yes ./scrypt.SlackBuild
+
+Before version 1.3.0 scrypt was able to read both passphrase and input
+file from standard input. This stopped to work in 1.3.0. In future
+versions it is planned to add an option to read passphrase using a
+variety of methods. This SlackBuild can patch scrypt 1.3.0 to add the
+option "--passphrase-env", which allows to read the passphrase from an
+environment variable. To this end, set the PASS environment variable:
+PASS=yes ./scrypt.SlackBuild
+
+The patch is taken fron the branch
+https://github.com/Tarsnap/scrypt/tree/passphrase-environ
+
+Warning: using this patch is not officially supported by upstream.