RSA Inspector
Inspect RSA public and private keys from PEM format. Shows key size in bits, public exponent, key type, and modulus — all decoded client-side using the Web Crypto API.
- Type
- Key size
- Public exponent
- Has private key
- Modulus (hex, truncated)
RSA Inspector
Inspect RSA public and private keys from PEM format. Decodes the key using the browser's native crypto.subtle Web Crypto API and displays the key type, bit length, public exponent, and modulus - no server upload required.
Frequently Asked Questions
Is my private key sent anywhere?
No. The key is parsed entirely in your browser using the Web Crypto API. It never leaves your machine. The page has no analytics on the key input field.
What PEM formats are supported?
PKCS#8 private keys (-----BEGIN PRIVATE KEY-----) and SPKI public keys (-----BEGIN PUBLIC KEY-----). Legacy PKCS#1 RSA headers (-----BEGIN RSA PRIVATE KEY-----) may not be supported by all browsers via SubtleCrypto.
What is the public exponent?
The public exponent e is used in RSA encryption and signature verification. The most common value is 65537 (0x10001), chosen for security and performance. A value of 3 is sometimes seen in older or constrained systems but is generally discouraged.
What key sizes are recommended?
2048-bit keys are the current minimum for most use cases. 4096-bit keys provide a higher security margin at the cost of slower operations. Keys below 2048 bits are considered insecure and should be rotated immediately.