(Ruby) Generate RSA Key and Sign a String

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Demonstrates how to generate a new RSA public/private key pair and use it to generate a signature for a string. The (binary) digital signature is returned as a hexidecimalized string.

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.

rsa = Chilkat::CkRsa.new()

# Generate a 2048-bit RSA key.
success = rsa.GenerateKey(2048)

# To return the signature in hex.
rsa.put_EncodingMode("hex")

strData = "This is the string to be signed."

# Sign the SHA256 hash of the string.
hexSig = rsa.signStringENC(strData,"sha256")

print hexSig + "\n";
print rsa.lastErrorText() + "\n";

# Now verify the signature:
success = rsa.VerifyStringENC(strData,"sha256",hexSig)
if (success == true)
    print "Signature verified!" + "\n";
else
    print rsa.lastErrorText() + "\n";
end

# Try it with an invalid signature:
success = rsa.VerifyStringENC(strData,"sha256","not a valid sig")
if (success == true)
    print "Signature verified!" + "\n";
else
    print rsa.lastErrorText() + "\n";
end

# Try it with invalid data:
success = rsa.VerifyStringENC("Not the original data","sha256",hexSig)
if (success == true)
    print "Signature verified!" + "\n";
else
    print rsa.lastErrorText() + "\n";
end

# Try it with the wrong hash algorithm:
success = rsa.VerifyStringENC(strData,"sha-1",hexSig)
if (success == true)
    print "Signature verified!" + "\n";
else
    print rsa.lastErrorText() + "\n";
end