cipher - The Go Programming Language

Golang

Package cipher

import "crypto/cipher"
Overview
Index

Overview ?

Overview ?

Package cipher implements standard block cipher modes that can be wrapped around low-level block cipher implementations. See http://csrc.nist.gov/groups/ST/toolkit/BCM/current_modes.html and NIST Special Publication 800-38A.

Index

type Block
type BlockMode
    func NewCBCDecrypter(b Block, iv []byte) BlockMode
    func NewCBCEncrypter(b Block, iv []byte) BlockMode
type Stream
    func NewCFBDecrypter(block Block, iv []byte) Stream
    func NewCFBEncrypter(block Block, iv []byte) Stream
    func NewCTR(block Block, iv []byte) Stream
    func NewOFB(b Block, iv []byte) Stream
type StreamReader
    func (r StreamReader) Read(dst []byte) (n int, err error)
type StreamWriter
    func (w StreamWriter) Close() error
    func (w StreamWriter) Write(src []byte) (n int, err error)

Package files

cbc.go cfb.go cipher.go ctr.go io.go ofb.go

type Block

type Block interface {
    // BlockSize returns the cipher's block size.
    BlockSize() int

    // Encrypt encrypts the first block in src into dst.
    // Dst and src may point at the same memory.
    Encrypt(dst, src []byte)

    // Decrypt decrypts the first block in src into dst.
    // Dst and src may point at the same memory.
    Decrypt(dst, src []byte)
}

A Block represents an implementation of block cipher using a given key. It provides the capability to encrypt or decrypt individual blocks. The mode implementations extend that capability to streams of blocks.

type BlockMode

type BlockMode interface {
    // BlockSize returns the mode's block size.
    BlockSize() int

    // CryptBlocks encrypts or decrypts a number of blocks. The length of
    // src must be a multiple of the block size. Dst and src may point to
    // the same memory.
    CryptBlocks(dst, src []byte)
}

A BlockMode represents a block cipher running in a block-based mode (CBC, ECB etc).

func NewCBCDecrypter

func NewCBCDecrypter(b Block, iv []byte) BlockMode

NewCBCDecrypter returns a BlockMode which decrypts in cipher block chaining mode, using the given Block. The length of iv must be the same as the Block's block size and must match the iv used to encrypt the data.

func NewCBCEncrypter

func NewCBCEncrypter(b Block, iv []byte) BlockMode

NewCBCEncrypter returns a BlockMode which encrypts in cipher block chaining mode, using the given Block. The length of iv must be the same as the Block's block size.

type Stream

type Stream interface {
    // XORKeyStream XORs each byte in the given slice with a byte from the
    // cipher's key stream. Dst and src may point to the same memory.
    XORKeyStream(dst, src []byte)
}

A Stream represents a stream cipher.

func NewCFBDecrypter

func NewCFBDecrypter(block Block, iv []byte) Stream

NewCFBDecrypter returns a Stream which decrypts with cipher feedback mode, using the given Block. The iv must be the same length as the Block's block size.

func NewCFBEncrypter

func NewCFBEncrypter(block Block, iv []byte) Stream

NewCFBEncrypter returns a Stream which encrypts with cipher feedback mode, using the given Block. The iv must be the same length as the Block's block size.

func NewCTR

func NewCTR(block Block, iv []byte) Stream

NewCTR returns a Stream which encrypts/decrypts using the given Block in counter mode. The length of iv must be the same as the Block's block size.

func NewOFB

func NewOFB(b Block, iv []byte) Stream

NewOFB returns a Stream that encrypts or decrypts using the block cipher b in output feedback mode. The initialization vector iv's length must be equal to b's block size.

type StreamReader

type StreamReader struct {
    S Stream
    R io.Reader
}

StreamReader wraps a Stream into an io.Reader. It calls XORKeyStream to process each slice of data which passes through.

func (StreamReader) Read

func (r StreamReader) Read(dst []byte) (n int, err error)

type StreamWriter

type StreamWriter struct {
    S   Stream
    W   io.Writer
    Err error
}

StreamWriter wraps a Stream into an io.Writer. It calls XORKeyStream to process each slice of data which passes through. If any Write call returns short then the StreamWriter is out of sync and must be discarded.

func (StreamWriter) Close

func (w StreamWriter) Close() error

func (StreamWriter) Write

func (w StreamWriter) Write(src []byte) (n int, err error)