| Maintainer | Thomas.DuBuisson@gmail.com |
|---|---|
| Stability | beta |
| Portability | portable |
| Safe Haskell | Safe-Inferred |
| Language | Haskell98 |
Crypto.Padding
Description
PKCS5 (RFC 1423) and IPSec ESP (RFC 4303)
padding methods are implemented both as trivial functions operating on
bytestrings and as PutM routines usable from the Data.Serialize
module. These methods do not work for algorithms or pad sizes in
excess of 255 bytes (2040 bits, so extremely large as far as cipher
needs are concerned).
Synopsis
- padPKCS5 :: ByteLength -> ByteString -> ByteString
- padBlockSize :: BlockCipher k => k -> ByteString -> ByteString
- putPaddedPKCS5 :: ByteLength -> ByteString -> Put
- unpadPKCS5safe :: ByteString -> Maybe ByteString
- unpadPKCS5 :: ByteString -> ByteString
- padESP :: Int -> ByteString -> ByteString
- unpadESP :: ByteString -> Maybe ByteString
- padESPBlockSize :: BlockCipher k => k -> ByteString -> ByteString
- putPadESPBlockSize :: BlockCipher k => k -> ByteString -> Put
- putPadESP :: Int -> ByteString -> Put
PKCS5 (RFC 1423) based [un]padding routines
padPKCS5 :: ByteLength -> ByteString -> ByteString Source #
PKCS5 (aka RFC1423) padding method. This method will not work properly for pad modulos > 256
padBlockSize :: BlockCipher k => k -> ByteString -> ByteString Source #
PKCS5 (aka RFC1423) padding method using the BlockCipher instance to determine the pad size.
putPaddedPKCS5 :: ByteLength -> ByteString -> Put Source #
Ex:
putPaddedPKCS5 m bs
Will pad out bs to a byte multiple
of m and put both the bytestring and it's padding via PutM
(this saves on copying if you are already using Cereal).
unpadPKCS5safe :: ByteString -> Maybe ByteString Source #
unpad a strict bytestring padded in the typical PKCS5 manner. This routine verifies all pad bytes and pad length match correctly.
unpadPKCS5 :: ByteString -> ByteString Source #
unpad a strict bytestring without checking the pad bytes and length any more than necessary.
ESP (RFC 4303) [un]padding routines
padESP :: Int -> ByteString -> ByteString Source #
Pad a bytestring to the IPSEC esp specification
padESP m payload
is equivilent to:
(msg) (padding) (length field)
B.concat [payload, B.pack [1,2,3,4..], B.pack [padLen]]
Where:
- the msg is any payload, including TFC.
- the padding is <= 255
- the length field is one byte.
Notice the result bytesting length remainder r equals zero. The lack
of a "next header" field means this function is not directly useable for
an IPSec implementation (copy/paste the 4 line function and add in a
"next header" field if you are making IPSec ESP).
unpadESP :: ByteString -> Maybe ByteString Source #
unpad and return the padded message (Nothing is returned if the padding is invalid)
padESPBlockSize :: BlockCipher k => k -> ByteString -> ByteString Source #
Like padESP but use the BlockCipher instance to determine padding size
putPadESPBlockSize :: BlockCipher k => k -> ByteString -> Put Source #
Like putPadESP but using the BlockCipher instance to determine padding size