(Ruby) Streaming Encryption by Encrypting in Chunks

Encrypt data in chunks.

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

require 'chilkat'

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

crypt = Chilkat::CkCrypt2.new()

crypt.put_CryptAlgorithm("aes")
crypt.put_CipherMode("cbc")
crypt.put_KeyLength(128)

crypt.SetEncodedKey("000102030405060708090A0B0C0D0E0F","hex")
crypt.SetEncodedIV("000102030405060708090A0B0C0D0E0F","hex")

crypt.put_EncodingMode("hex")
txt1 = "The quick brown fox jumped over the lazy dog.\r\n"
txt2 = "-\r\n"
txt3 = "Done.\r\n"

sbEncrypted = Chilkat::CkStringBuilder.new()

# Encrypt the 1st chunk:
# (don't worry about feeding the data to the encryptor in 
# exact multiples of the encryption algorithm's block size.
# Chilkat will buffer the data.)
crypt.put_FirstChunk(true)
crypt.put_LastChunk(false)
sbEncrypted.Append(crypt.encryptStringENC(txt1))

# Encrypt the 2nd chunk
crypt.put_FirstChunk(false)
crypt.put_LastChunk(false)
sbEncrypted.Append(crypt.encryptStringENC(txt2))

# Now encrypt N more chunks...
# Remember -- we're doing this in CBC mode, so each call
# to the encrypt method depends on the state from previous
# calls...
crypt.put_FirstChunk(false)
crypt.put_LastChunk(false)

for i in 0 .. 4
    sbEncrypted.Append(crypt.encryptStringENC(txt1))
    sbEncrypted.Append(crypt.encryptStringENC(txt2))
end

# Now encrypt the last chunk:
crypt.put_FirstChunk(false)
crypt.put_LastChunk(true)
sbEncrypted.Append(crypt.encryptStringENC(txt3))

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

# Now decrypt in one call.
# (The data we're decrypting is both the first AND last chunk.)  
crypt.put_FirstChunk(true)
crypt.put_LastChunk(true)
decryptedText = crypt.decryptStringENC(sbEncrypted.getAsString())

print decryptedText + "\n";

# Note: You may decrypt in N chunks by setting the FirstChunk
# and LastChunk properties prior to calling the Decrypt* methods