AES-128-CBC-HMAC-SHA1 ENCRYPTION TOOL
Other Crypto Algorithms
AES-128-CBC AES-128-CBC-CTS AES-128-CBC-HMAC-SHA1 AES-128-CBC-HMAC-SHA256 AES-128-CCM AES-128-CFB AES-128-CFB1 AES-128-CFB8 AES-128-CTR AES-128-ECB AES-128-GCM AES-128-GCM-SIV AES-128-OCB AES-128-OFB AES-128-SIV AES-128-WRAP AES-128-WRAP-INV AES-128-WRAP-PAD AES-128-WRAP-PAD-INV AES-128-XTS AES-192-CBC AES-192-CBC-CTS AES-192-CCM AES-192-CFB AES-192-CFB1 AES-192-CFB8 AES-192-CTR AES-192-ECB AES-192-GCM AES-192-GCM-SIV AES-192-OCB AES-192-OFB AES-192-SIV AES-192-WRAP AES-192-WRAP-INV AES-192-WRAP-PAD AES-192-WRAP-PAD-INV AES-256-CBC AES-256-CBC-CTS AES-256-CBC-HMAC-SHA1 AES-256-CBC-HMAC-SHA256 AES-256-CCM AES-256-CFB AES-256-CFB1 AES-256-CFB8 AES-256-CTR AES-256-ECB AES-256-GCM AES-256-GCM-SIV AES-256-OCB AES-256-OFB AES-256-SIV AES-256-WRAP AES-256-WRAP-INV AES-256-WRAP-PAD AES-256-WRAP-PAD-INV AES-256-XTS ARIA-128-CBC ARIA-128-CCM ARIA-128-CFB ARIA-128-CFB1 ARIA-128-CFB8 ARIA-128-CTR ARIA-128-ECB ARIA-128-GCM ARIA-128-OFB ARIA-192-CBC ARIA-192-CCM ARIA-192-CFB ARIA-192-CFB1 ARIA-192-CFB8 ARIA-192-CTR ARIA-192-ECB ARIA-192-GCM ARIA-192-OFB ARIA-256-CBC ARIA-256-CCM ARIA-256-CFB ARIA-256-CFB1 ARIA-256-CFB8 ARIA-256-CTR ARIA-256-ECB ARIA-256-GCM ARIA-256-OFB CAMELLIA-128-CBC CAMELLIA-128-CBC-CTS CAMELLIA-128-CFB CAMELLIA-128-CFB1 CAMELLIA-128-CFB8 CAMELLIA-128-CTR CAMELLIA-128-ECB CAMELLIA-128-OFB CAMELLIA-192-CBC CAMELLIA-192-CBC-CTS CAMELLIA-192-CFB CAMELLIA-192-CFB1 CAMELLIA-192-CFB8 CAMELLIA-192-CTR CAMELLIA-192-ECB CAMELLIA-192-OFB CAMELLIA-256-CBC CAMELLIA-256-CBC-CTS CAMELLIA-256-CFB CAMELLIA-256-CFB1 CAMELLIA-256-CFB8 CAMELLIA-256-CTR CAMELLIA-256-ECB CAMELLIA-256-OFB CHACHA20 CHACHA20-POLY1305 DES-EDE-CBC DES-EDE-CFB DES-EDE-ECB DES-EDE-OFB DES-EDE3-CBC DES-EDE3-CFB DES-EDE3-CFB1 DES-EDE3-CFB8 DES-EDE3-ECB DES-EDE3-OFB DES3-WRAPThe AES-128-CBC-HMAC-SHA1 algorithm is a symmetric encryption scheme combined with an integrity verification mechanism. It utilizes the Advanced Encryption Standard (AES) with a 128-bit key in Cipher Block Chaining (CBC) mode for encryption, and HMAC with SHA-1 for authentication. The algorithm ensures both confidentiality and integrity of the processed data.
Encryption Process
The encryption process begins with the generation of a random initialization vector (IV) of 16 bytes. The plaintext is divided into blocks of 16 bytes. Each block is XORed with the previous ciphertext block or the IV for the first block, then encrypted using the AES-128 cipher. This chaining ensures that identical plaintext blocks result in distinct ciphertext blocks, preventing pattern leakage. Padding is applied using a standard scheme such as PKCS#7 to ensure the last block is a full 16 bytes.
Authentication Process
After encryption, an HMAC is computed over the concatenation of the IV and ciphertext using the SHA-1 hash function and a separate authentication key derived from the original encryption key. The resulting HMAC ensures that any modification to the ciphertext or IV can be detected. The final output of the algorithm consists of the IV, ciphertext, and HMAC tag.
Decryption Process
Decryption requires verification of the HMAC before decrypting the ciphertext. The recipient computes an HMAC over the received IV and ciphertext and compares it with the transmitted HMAC. If the values match, the ciphertext is decrypted block by block using AES-128 in CBC mode, reversing the XOR operation with the previous ciphertext block or IV. After decryption, the padding is removed to recover the original plaintext.
Security Considerations
Using AES-128-CBC ensures strong encryption against brute-force attacks, while HMAC-SHA1 provides integrity verification against tampering. The separation of encryption and authentication keys is critical for security. Proper generation and management of the IV and cryptographic keys are essential to prevent vulnerabilities such as padding oracle attacks and key reuse.
Applications
The AES-128-CBC-HMAC-SHA1 algorithm is commonly used in secure communication protocols, file encryption systems, and data storage solutions where both confidentiality and integrity are required. Its combined approach allows safe transmission of sensitive information in environments where attackers may attempt both passive and active attacks.