Supported algorithms
ocrypto supports the following cryptographic algorithms:
| Algorithm | Specification |
| SHA (SHA512, SHA384*, SHA256, SHA224*, SHA1) | FIPS-PUB-180-4 |
| AEAD-ChaCha20-Poly1305 | RFC8439 |
| AES (CTR, CCM, GCM, CBC, ECB, EAX with 128/192/256-bit keys) | FIPS-PUB-197, NIST SP 800-38*, EAX |
| AES-CMAC | RFC4493 |
| HMAC (SHA512, SHA256, SHA1) | RFC2104 |
| HKDF (SHA512, SHA256, SHA1) | RFC5869 |
| PBKDF2 (SHA256, SHA1) | RFC8018 |
| ECDH (P224, P256) ** | NIST SP 800-56A |
| ECDSA (P224, P256) ** | FIPS-PUB-186-4 |
| X25519 (aka Curve25519) | RFC7748 |
| Ed25519 | RFC8032 |
| RSA (1024- and 2048-bit keys, PKCS1 V1.5, OAEP, PSS) | RFC8017 |
| SRP-6 (SHA512, 3072-bit keys) | RFC2945 |
| EC-JPAKE (P256) |
RFC8236 |
| SRTP crypto functions *** | RFC3711 |
* SHA512 with output truncated to 384 bit / SHA256 with output truncated to 224 bit.
** P224 (aka prime224v1 and secp224r1) and P256 (aka prime256v1 and secp256r1) are implemented according to RFC5903.
*** Support for SRTP default crypto algorithms (AES-CTR and HMAC-SHA1).
Supported function types
ocrypto supports these three types of functions:
| Function type | Description |
| Single-part | Function is executed in a single call, using only the stack. |
| Stack-optimized |
Function is executed in a single call, using minimal stack space. Additional memory is provided by caller in a context object. |
| Incremental |
Function is executed in multiple calls, to allow for streams of data to be processed in a piecemeal fashion. Additional memory is provided by caller in a context object. |
This table shows which function types are supported for which algorithms:
| Algorithm | Single-part | Stack-optimized | Incremental |
| SHA | x | x | |
| AEAD-ChaCha20-Poly1305 | x | x | |
| AES | x | x | |
| AES-CMAC | x | ||
| HMAC |
x |
||
| HKDF | x | ||
| PBKDF2 | x | ||
| ECDH | x | ||
| ECDSA | x | ||
| X25519 | x | x | |
| Ed25519 | x | x | |
| RSA | x | ||
| SRP-6 | x | x | |
| EC-JPAKE | x | ||
| SRTP crypto functions | x |
To learn more about the RAM memory sizes required by the different types of functions, see this page.