(Ruby) AES and CHACHA20 Encrypt/Decrypt Text

Demonstrates the use of the new EncryptSb and DecryptSb methods introduced in Chilkat v9.5.0.67 to encrypt/decrypt the contents of StringBuilder objects.

Note: This example requires Chilkat v9.5.0.67 or greater.

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# First build a string to be encrypted
sb = Chilkat::CkStringBuilder.new()
i = 1
while i < 10
    sb.AppendInt(i)
    sb.Append(" the quick brown fox jumped over the lazy dog.\r\n")
    i = i + 1
end

print sb.getAsString() + "\n";

# The string to be encrypted looks like this:

# 1 the quick brown fox jumped over the lazy dog.
# 2 the quick brown fox jumped over the lazy dog.
# 3 the quick brown fox jumped over the lazy dog.
# 4 the quick brown fox jumped over the lazy dog.
# 5 the quick brown fox jumped over the lazy dog.
# 6 the quick brown fox jumped over the lazy dog.
# ...

crypt = Chilkat::CkCrypt2.new()

# Specify the encryption to be used.
# First we'll do AES-128 CBC
crypt.put_CryptAlgorithm("aes")
crypt.put_CipherMode("cbc")
crypt.put_KeyLength(128)

ivHex = "000102030405060708090A0B0C0D0E0F"
crypt.SetEncodedIV(ivHex,"hex")

keyHex = "000102030405060708090A0B0C0D0E0F101112131415161718191A1B1C1D1E1F"
crypt.SetEncodedKey(keyHex,"hex")

# When EncryptSb is called, the contents of the source (sb)
# remains unmodified.  The encrypted bytes are written into bdEncrypted.
# If bdEncrypted already contained data, it is replaced with the encrypted bytes.
bdEncrypted = Chilkat::CkBinData.new()
success = crypt.EncryptSb(sb,bdEncrypted)
if (success != true)
    print crypt.lastErrorText() + "\n";
    exit
end

# Examine the encrypted bytes:
print bdEncrypted.getEncoded("base64_mime") + "\n";

# Sample encrypted data:

# 0DdNZ22ckMMJBiaKhAu3wUEfh16XW356NIUsDmNs/xwbHe/p1201OmpfzwXwKktkAefu2pckrBgC
# df+1w8lRo+KAy5n5wlAgMGM/UrsVJsp0BmDPk1vaxKrmrGpSXOVCQs1n2+0atIs5YLiOG+Va3+Mi
# EQNb4YK7bNMmvt0++irBxTiGnkx/RncfKwgkbBUpl2x7yV13MW6lapDT6Md0DKAMsTXFJYGeIdEf
# g2uxDDQzI5gUOUHTMrXQ8paD/K76KKB9Jpp/kAM9z8g/d8KUmuphA7KI64d38xsgOmcITlbhlCQ2
# PDkcU6RRzX0FUTUSMgQukhy0jkLZEjHX9poKJD+iJTOkcQUC3OqR9hKhSrvIgJN4lxdR71MheOoQ
# 2wmvRdq+agTWWh333Vmb6J6yDV79aSpnqEDrA8Ks7Xzciol0gve91+JtVJlJKjWwEzWEU8GxF7Q8
# eaWI70lsC5nTLGcbqgKu6gzkzHlHyHaE2FAQA/d5I2dvfsAYUQCza0Zdyw8mmTtHhlP2Tfxj1uPv
# H4Q7BGuKnx3SWT2CnpbX4091w7KzLAztrbFBo/Tf9w8ZpgTK9k1ryfW9/xnk6rW6iQ==

# Decrypt to restore back to the original:
sbOriginal = Chilkat::CkStringBuilder.new()
success = crypt.DecryptSb(bdEncrypted,sbOriginal)
if (success != true)
    print crypt.lastErrorText() + "\n";
    exit
end

# Examine the original data:
print sbOriginal.getAsString() + "\n";

# ----------------------------------------------------------------------------------
# To do chacha20 encryption, just change the settings:

crypt.put_CryptAlgorithm("chacha20")
crypt.put_KeyLength(256)
# The initial count is the initial block counter for the chacha20 algorithm.
# It can be any integer, but must be set to the same when decrypting.
crypt.put_InitialCount(22)

# EncryptSb completely replaces the contents of bdEncrypted.
success = crypt.EncryptSb(sb,bdEncrypted)

# However.. DecryptSb appends the decrypted text to whatever may
# have already existed within sbOriginal.
success = crypt.DecryptSb(bdEncrypted,sbOriginal)

print "----" + "\n";
print "The original data should be here twice.  Once from the AES decrypt, and again from the chacha20 decrypt." + "\n";
print sbOriginal.getAsString() + "\n";
print "Success." + "\n";