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54 lines
1.4 KiB
54 lines
1.4 KiB
// +build !without_openssl |
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package stupidgcm |
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import ( |
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"crypto/cipher" |
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"log" |
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"golang.org/x/crypto/chacha20poly1305" |
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) |
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/* |
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#include <openssl/evp.h> |
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*/ |
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import "C" |
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type stupidChacha20poly1305 struct { |
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stupidAEADCommon |
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} |
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// Verify that we satisfy the cipher.AEAD interface |
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var _ cipher.AEAD = &stupidChacha20poly1305{} |
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// _EVP_chacha20_poly1305 caches C.EVP_chacha20_poly1305() to avoid the Cgo call |
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// overhead for each instantiation of NewChacha20poly1305. |
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var _EVP_chacha20_poly1305 *C.EVP_CIPHER |
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func init() { |
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_EVP_chacha20_poly1305 = C.EVP_chacha20_poly1305() |
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} |
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// NewChacha20poly1305 returns a new instance of the OpenSSL ChaCha20-Poly1305 AEAD |
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// cipher ( https://www.openssl.org/docs/man1.1.1/man3/EVP_chacha20_poly1305.html ). |
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// |
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// gocryptfs only uses ChaCha20-Poly1305 as a building block for OpenSSL |
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// XChaCha20-Poly1305. This function is hot because it gets called once for each |
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// block by XChaCha20-Poly1305. |
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// |
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// Only 32-bytes keys and 12-byte IVs are supported. |
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func NewChacha20poly1305(key []byte) *stupidChacha20poly1305 { |
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if len(key) != chacha20poly1305.KeySize { |
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log.Panicf("Only %d-byte keys are supported, you passed %d bytes", chacha20poly1305.KeySize, len(key)) |
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} |
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// private copy |
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key2 := make([]byte, chacha20poly1305.KeySize) |
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copy(key2, key) |
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return &stupidChacha20poly1305{ |
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stupidAEADCommon{ |
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key: key2, |
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openSSLEVPCipher: _EVP_chacha20_poly1305, |
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nonceSize: chacha20poly1305.NonceSize, |
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}, |
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} |
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}
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