nimcrypto/examples/ecb.nim

143 lines
4.4 KiB
Nim

#
#
# NimCrypto
# (c) Copyright 2016-2018 Eugene Kabanov
#
# See the file "LICENSE", included in this
# distribution, for details about the copyright.
#
## This is example of usage ``ECB[T]`` encryption/decryption.
import nimcrypto
var aliceKey = "Alice Key"
var aliceData = "Alice hidden secret"
block:
## Nim's way API using openArray[byte].
var ectx, dctx: ECB[aes256]
var key: array[aes256.sizeKey, byte]
var plainText: array[aes256.sizeBlock * 2, byte]
var encText: array[aes256.sizeBlock * 2, byte]
var decText: array[aes256.sizeBlock * 2, byte]
# AES256 block size is 128 bits or 16 bytes, so we need to pad plaintext with
# 0 bytes.
# WARNING! Do not use 0 byte padding in applications, this is done
# as example.
copyMem(addr plainText[0], addr aliceData[0], len(aliceData))
# AES256 key size is 256 bits or 32 bytes, so we need to pad key with
# 0 bytes.
# WARNING! Do not use 0 byte padding in applications, this is done
# as example.
copyMem(addr key[0], addr aliceKey[0], len(aliceKey))
# Initialization of ECB[aes256] context with encryption key
ectx.init(key)
# Encryption process
ectx.encrypt(plainText, encText)
# Clear context of ECB[aes256]
ectx.clear()
# Initialization of ECB[aes256] context with encryption key
dctx.init(key)
# Decryption process
dctx.decrypt(encText, decText)
# Clear context of ECB[aes256]
dctx.clear()
echo "PLAIN TEXT: ", toHex(plainText)
echo "ENCODED TEXT: ", toHex(encText)
echo "DECODED TEXT: ", toHex(decText)
assert(equalMem(addr plainText[0], addr decText[0], len(plainText)))
block:
## UNSAFE way API pointer/size.
var ectx, dctx: ECB[aes256]
var key: array[aes256.sizeKey, byte]
var plainText: array[aes256.sizeBlock * 2, byte]
var encText: array[aes256.sizeBlock * 2, byte]
var decText: array[aes256.sizeBlock * 2, byte]
var ptrKey = cast[ptr byte](addr key[0])
var ptrPlainText = cast[ptr byte](addr plainText[0])
var ptrEncText = cast[ptr byte](addr encText[0])
var ptrDecText = cast[ptr byte](addr decText[0])
let dataLen = uint(len(plainText))
# AES256 block size is 128 bits or 16 bytes, so we need to pad plaintext with
# 0 bytes.
# WARNING! Do not use 0 byte padding in applications, this is done
# as example.
copyMem(addr plainText[0], addr aliceData[0], len(aliceData))
# AES256 key size is 256 bits or 32 bytes, so we need to pad key with
# 0 bytes.
# WARNING! Do not use 0 byte padding in applications, this is done
# as example.
copyMem(addr key[0], addr aliceKey[0], len(aliceKey))
# Initialization of ECB[aes256] context with encryption key
ectx.init(ptrKey)
# Encryption process
ectx.encrypt(ptrPlainText, ptrEncText, dataLen)
# Clear context of ECB[aes256]
ectx.clear()
# Initialization of ECB[aes256] context with encryption key
dctx.init(ptrKey)
# Decryption process
dctx.decrypt(ptrEncText, ptrDecText, dataLen)
# Clear context of ECB[aes256]
dctx.clear()
echo "PLAIN TEXT: ", toHex(plainText)
echo "ENCODED TEXT: ", toHex(encText)
echo "DECODED TEXT: ", toHex(decText)
assert(equalMem(addr plainText[0], addr decText[0], len(plainText)))
block:
## Nim's way API using strings.
var ectx, dctx: ECB[aes256]
var key = newString(aes256.sizeKey)
var plainText = newString(aes256.sizeBlock * 2)
var encText = newString(aes256.sizeBlock * 2)
var decText = newString(aes256.sizeBlock * 2)
# AES256 block size is 128 bits or 16 bytes, so we need to pad plaintext with
# 0 bytes.
# WARNING! Do not use 0 byte padding in applications, this is done
# as example.
copyMem(addr plainText[0], addr aliceData[0], len(aliceData))
# AES256 key size is 256 bits or 32 bytes, so we need to pad key with
# 0 bytes.
# WARNING! Do not use 0 byte padding in applications, this is done
# as example.
copyMem(addr key[0], addr aliceKey[0], len(aliceKey))
# Initialization of ECB[aes256] context with encryption key
ectx.init(key)
# Encryption process
ectx.encrypt(plainText, encText)
# Clear context of ECB[aes256]
ectx.clear()
# Initialization of ECB[aes256] context with encryption key
dctx.init(key)
# Decryption process
dctx.decrypt(encText, decText)
# Clear context of ECB[aes256]
dctx.clear()
echo "PLAIN TEXT: ", $plainText
echo "ENCODED TEXT: ", $encText
echo "DECODED TEXT: ", $decText
assert(equalMem(addr plainText[0], addr decText[0], len(plainText)))