Classic ASP
Classic ASP
ChaCha20 Encryption
See more Encryption Examples
Demonstrates ChaCha20 encryption and decryption. (Introduced in Chilkat v9.5.0.55) This example duplicates the results of Test Vector #3 for ChaCha20 Encryption in RFC 7539.Chilkat Classic ASP Downloads
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' This example assumes the Chilkat API to have been previously unlocked.
' See Global Unlock Sample for sample code.
set crypt = Server.CreateObject("Chilkat.Crypt2")
' Set the encryption algorithm to chacha20
' chacha20 is a stream cipher, and therefore no cipher mode applies.
crypt.CryptAlgorithm = "chacha20"
' The key length for chacha20 is always 256-bits.
crypt.KeyLength = 256
' Note: "padding" only applies to block encryption algorithmns.
' Since chacha20 is a stream cipher, there is no padding and the output
' number of bytes is exactly equal to the input.
' EncodingMode specifies the encoding of the output for
' encryption, and the input for decryption.
' Valid modes are (case insensitive) "Base64", "modBase64", "Base32", "Base58", "UU",
' "QP" (for quoted-printable), "URL" (for url-encoding), "Hex",
' "Q", "B", "url_oauth", "url_rfc1738", "url_rfc2396", and "url_rfc3986".
crypt.EncodingMode = "hex"
' The inputs to ChaCha20 encryption, specified by RFC 7539, are:
' 1) A 256-bit secret key.
' 2) A 96-bit nonce.
' 3) A 32-bit initial count.
' The IV property is used to specify the chacha20 nonce.
' For a 96-bit nonce, the IV should be 12 bytes in length.
'
' Note: Some implementations of chacha20, such as that used internally by SSH,
' use a 64-bit nonce and 64-bit count. To do chacha20 encryption in this way,
' simply provide 8 bytes for the IV instead of 12 bytes. Chilkat will then automatically
' use 8 bytes (64-bits) for the count.
' This example duplicates Test Vector #3 (for ChaCha20 encryption) from RFC 7539.
ivHex = "000000000000000000000002"
crypt.SetEncodedIV ivHex,"hex"
crypt.InitialCount = 42
keyHex = "1c9240a5eb55d38af333888604f6b5f0473917c1402b80099dca5cbc207075c0"
crypt.SetEncodedKey keyHex,"hex"
plainText = "'Twas brillig, and the slithy toves" & vbLf & "Did gyre and gimble in the wabe:" & vbLf & "All mimsy were the borogoves," & vbLf & "And the mome raths outgrabe."
encStr = crypt.EncryptStringENC(plainText)
Response.Write "<pre>" & Server.HTMLEncode( encStr) & "</pre>"
' Now decrypt:
decStr = crypt.DecryptStringENC(encStr)
Response.Write "<pre>" & Server.HTMLEncode( decStr) & "</pre>"
' Here is the Test Vector data copied from RFC 7539
' Test Vector #3:
' ==============
'
' Key:
' 000 1c 92 40 a5 eb 55 d3 8a f3 33 88 86 04 f6 b5 f0 ..@..U...3......
' 016 47 39 17 c1 40 2b 80 09 9d ca 5c bc 20 70 75 c0 G9..@+....\. pu.
'
' Nonce:
' 000 00 00 00 00 00 00 00 00 00 00 00 02 ............
'
' Initial Block Counter = 42
'
' Plaintext:
' 000 27 54 77 61 73 20 62 72 69 6c 6c 69 67 2c 20 61 'Twas brillig, a
' 016 6e 64 20 74 68 65 20 73 6c 69 74 68 79 20 74 6f nd the slithy to
' 032 76 65 73 0a 44 69 64 20 67 79 72 65 20 61 6e 64 ves.Did gyre and
' 048 20 67 69 6d 62 6c 65 20 69 6e 20 74 68 65 20 77 gimble in the w
' 064 61 62 65 3a 0a 41 6c 6c 20 6d 69 6d 73 79 20 77 abe:.All mimsy w
' 080 65 72 65 20 74 68 65 20 62 6f 72 6f 67 6f 76 65 ere the borogove
' 096 73 2c 0a 41 6e 64 20 74 68 65 20 6d 6f 6d 65 20 s,.And the mome
' 112 72 61 74 68 73 20 6f 75 74 67 72 61 62 65 2e raths outgrabe.
'
' Ciphertext:
' 000 62 e6 34 7f 95 ed 87 a4 5f fa e7 42 6f 27 a1 df b.4....._..Bo'..
' 016 5f b6 91 10 04 4c 0d 73 11 8e ff a9 5b 01 e5 cf _....L.s....[...
' 032 16 6d 3d f2 d7 21 ca f9 b2 1e 5f b1 4c 61 68 71 .m=..!...._.Lahq
' 048 fd 84 c5 4f 9d 65 b2 83 19 6c 7f e4 f6 05 53 eb ...O.e...l....S.
' 064 f3 9c 64 02 c4 22 34 e3 2a 35 6b 3e 76 43 12 a6 ..d.."4.*5k>vC..
' 080 1a 55 32 05 57 16 ea d6 96 25 68 f8 7d 3f 3f 77 .U2.W....%h.}??w
' 096 04 c6 a8 d1 bc d1 bf 4d 50 d6 15 4b 6d a7 31 b1 .......MP..Km.1.
' 112 87 b5 8d fd 72 8a fa 36 75 7a 79 7a c1 88 d1 ....r..6uzyz..
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