Tcl

Generating Repeatable Random Data for Testing/Debugging

See more PRNG Examples

Demonstrates how to use the Fortuna PRNG to generate random-looking but repeatable non-random data for the purpose of testing and debugging. Tcl

load ./chilkat.dll

set success 0

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

set success 0

set fortuna [new_CkPrng]

# Normally an application would seed the PRNG with entropy from
# some real random source.  However, sometimes we want the same
# random sequence of bytes for testing and debugging purposes.
# This a reason why GetEntropy and AddEntropy are two different methods.
# An application could omit the call to GetEntropy, and instead pass
# non-random data to AddEntropy. For example:

# Seed the PRNG with non-entropy, so we get a repeatable sequence.
# Note: AddEntropy can be called any number of times.
set success [CkPrng_AddEntropy $fortuna "01020304" "hex"]
set success [CkPrng_AddEntropy $fortuna "hello world" "ascii"]

# Generate some random data:
set strRandHex [CkPrng_genRandom $fortuna 16 "hex"]
set strRandBase64 [CkPrng_genRandom $fortuna 22 "base64"]
set strRandBase58 [CkPrng_genRandom $fortuna 32 "base58"]

puts "hex random bytes: $strRandHex"
puts "base64 random bytes: $strRandBase64"
puts "base58 random bytes: $strRandBase58"

# Try it again with a different object to verify that the same results are obtained:
set fortuna2 [new_CkPrng]

set success [CkPrng_AddEntropy $fortuna2 "01020304" "hex"]
set success [CkPrng_AddEntropy $fortuna2 "hello world" "ascii"]

set strRandHex [CkPrng_genRandom $fortuna2 16 "hex"]
set strRandBase64 [CkPrng_genRandom $fortuna2 22 "base64"]
set strRandBase58 [CkPrng_genRandom $fortuna2 32 "base58"]

puts "hex random bytes: $strRandHex"
puts "base64 random bytes: $strRandBase64"
puts "base58 random bytes: $strRandBase58"

delete_CkPrng $fortuna
delete_CkPrng $fortuna2