Understanding Encryption Technologies

2 min read Infrastructure & DevOps Security

Understanding Encryption Technologies

Encryption transforms readable data into ciphertext using mathematical algorithms and encryption keys. Understanding different encryption types, algorithms, and their appropriate use cases helps administrators implement effective data protection strategies. The choice between symmetric and asymmetric encryption, along with algorithm selection, significantly impacts both security and performance.

Symmetric encryption uses the same key for both encryption and decryption, providing fast performance suitable for large data volumes. Common symmetric algorithms include AES (Advanced Encryption Standard), which offers 128, 192, and 256-bit key lengths. AES-256 represents the current gold standard for symmetric encryption:

# Generate random AES-256 key
openssl rand -hex 32 > aes256.key

# Encrypt file with AES-256
openssl enc -aes-256-cbc -salt -in sensitive.doc -out sensitive.doc.enc -pass file:aes256.key

# Decrypt file
openssl enc -d -aes-256-cbc -in sensitive.doc.enc -out sensitive.doc -pass file:aes256.key

Asymmetric encryption uses paired public and private keys, enabling secure key exchange and digital signatures. RSA and Elliptic Curve Cryptography (ECC) represent common asymmetric algorithms:

# Generate RSA key pair in Windows
$RSA = [System.Security.Cryptography.RSA]::Create(4096)
$PublicKey = $RSA.ExportRSAPublicKey()
$PrivateKey = $RSA.ExportRSAPrivateKey()

# Save keys
[System.IO.File]::WriteAllBytes("public.key", $PublicKey)
[System.IO.File]::WriteAllBytes("private.key", $PrivateKey)

# Encrypt data with public key
$RSAPublic = [System.Security.Cryptography.RSA]::Create()
$RSAPublic.ImportRSAPublicKey([System.IO.File]::ReadAllBytes("public.key"), [ref]$null)
$PlainText = [System.Text.Encoding]::UTF8.GetBytes("Sensitive data")
$CipherText = $RSAPublic.Encrypt($PlainText, [System.Security.Cryptography.RSAEncryptionPadding]::OaepSHA256)

Hash functions provide data integrity verification without encryption. While not reversible, cryptographic hashes ensure data hasn't been modified:

# Generate file hashes
sha256sum important.pdf > important.pdf.sha256
sha512sum database.sql > database.sql.sha512

# Verify integrity
sha256sum -c important.pdf.sha256
sha512sum -c database.sql.sha512

# HMAC for authenticated hashing
echo -n "message" | openssl dgst -sha256 -hmac "secret_key"

Key management represents the most critical aspect of encryption implementation. Poor key management undermines even the strongest encryption algorithms. Implement key rotation, secure storage, and access controls to protect encryption keys from unauthorized access.