diff --git a/cybersec/security/Building Secure and Reliable Systems.pdf b/cybersec/security/Building Secure and Reliable Systems.pdf
new file mode 100644
index 0000000..ede1187
Binary files /dev/null and b/cybersec/security/Building Secure and Reliable Systems.pdf differ
diff --git a/cybersec/security/Serious_cryptography.pdf b/cybersec/security/Serious_cryptography.pdf
new file mode 100644
index 0000000..b6e2e34
Binary files /dev/null and b/cybersec/security/Serious_cryptography.pdf differ